Analysis of SOI-MEMS Electrostatic Vibration Energy Harvester
高密度阳极铝电解槽电
第 54 卷第 2 期2023 年 2 月中南大学学报(自然科学版)Journal of Central South University (Science and Technology)V ol.54 No.2Feb. 2023高密度阳极铝电解槽电−热场耦合仿真研究魏兴国1，廖成志1，侯文渊1, 2，段鹏1，李贺松1(1. 中南大学 能源科学与工程学院，湖南 长沙，410083；2. 中北大学 能源与动力工程学院，山西 太原，030051)摘要：在铝电解槽中，阳极炭块内存在的气孔会降低炭块的导电和导热性能，并且增加炭渣，降低电流效率，导致炭耗和直流电耗升高。
通过浸渍工艺得到的高密度阳极可以有效地降低炭块的气孔率。
为了探究高密度阳极铝电解槽的电−热场变化和影响，基于ANSYS 软件建立高密度阳极铝电解槽的电−热场耦合计算模型。
研究结果表明：铝电解槽高密度阳极炭块的平均温度上升8.73 ℃，热应力增加，但形变量减小；侧部槽壳的平均温度下降28.59 ℃，热应力和形变量均降低，有利于保持槽膛内形稳定；热场变化主要与阳极炭块物性改变有关；槽电压降低49.16 mV ，主要与炭块物性改变和电解质电阻率降低有关；高密度阳极电流全导通时间缩短3.39 h ，可有效减弱换极产生的负面影响，阳极使用寿命可延长4 d ，炭耗降低10.3 kg/t ；铝电解槽反应能耗占比增加0.62%，电流效率提高1.69%，直流电耗降低270 kW·h/t 。
关键词：铝电解槽；高密度阳极；电−热场；耦合仿真中图分类号：TF821 文献标志码：A 文章编号：1672-7207（2023）02-0744-10Simulation study of electric-thermal field coupling in high-densityanode aluminum electrolyzerWEI Xingguo 1, LIAO Chengzhi 1, HOU Wenyuan 1, 2, DUAN Peng 1, LI Hesong 1(1. School of Energy Science and Engineering, Central South University, Changsha 410083, China;2. School of Energy and Power Engineering, North University of China, Taiyuan 030051, China)Abstract: In aluminum electrolytic cells, porosity in anode carbon blocks can reduce the electrical and thermal conductivity of the blocks and increase carbon slag, reduce current efficiency and lead to higher carbon consumption and DC power consumption. High-density anodes obtained by impregnation process can effectively reduce the porosity of carbon blocks. In order to investigate the electric-thermal field variation and the causes of influence in the high-density anode aluminum electrolyzer, a coupled electric-thermal field calculation model of收稿日期： 2022 −07 −11； 修回日期： 2022 −08 −20基金项目(Foundation item)：国家高技术研究发展项目(2010AA065201)；中南大学研究生自主探索创新项目(2021zzts0668)(Project(2010AA065201) supported by the National High-Tech Research and Development Program of China; Project (2021zzts0668) supported by the Independent Exploration and Innovation of Graduate Students in Central South University)通信作者：李贺松，博士，教授，博士生导师，从事铝电解研究；E-mail:****************.cnDOI: 10.11817/j.issn.1672-7207.2023.02.032引用格式： 魏兴国, 廖成志, 侯文渊, 等. 高密度阳极铝电解槽电−热场耦合仿真研究[J]. 中南大学学报(自然科学版), 2023, 54(2): 744−753.Citation: WEI Xingguo, LIAO Chengzhi, HOU Wenyuan, et al. Simulation study of electric-thermal field coupling in high-density anode aluminum electrolyzer[J]. Journal of Central South University(Science and Technology), 2023, 54(2): 744−753.第 2 期魏兴国，等：高密度阳极铝电解槽电−热场耦合仿真研究the high-density anode aluminum electrolyzer was established based on ANSYS software. The results show that the average temperature of the anode carbon block increases by 8.73 ℃ when the high-density anode is put on the tank, and the thermal stress increases but the deformation variable decreases. The average temperature of the side shell decreases by 28.59 ℃, and the thermal stress and deformation variable both decrease,which helps to protect the inner shape of the tank chamber stable. The change of the thermal field is mainly related to the change of the physical properties of the anode carbon block. The cell voltage decreases by 49.16 mV which is mainly related to the change of carbon block physical ploperties and the decrease of electrolyte resistivity, respectively. The reduction of 3.39 h in the full conduction time of high-density anode current can effectively reduce the negative effects of electrode change, and the anode service life can be extended by 4 d. The carbon consumption is reduced by 10.3 kg/t. The reaction energy consumption of aluminum electrolyzer is increased by 0.62%, the current efficiency is increased by 1.69%, and the DC power consumption is reduced by 270 kW·h/t.Key words: aluminum electrolyzer; high-density anode; electric-thermal field; coupling simulation作为铝电解槽的核心部件，阳极炭块在反应过程中被不断消耗，其品质直接影响着各项经济技术指标[1]。
新型部分耗尽SOI器件体接触结构
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基于SOI_MEMS技术的静电驱动_电容检测硅谐振器_英文_焦海龙1_2_陈德勇
网络出版时间：2013-05-08 15:12网络出版地址：/kcms/detail/12.1351.O3.20130508.1512.001.html纳米技术与精密工程An Electrostatically Driven - Capacitively Sensed Silicon ResonatorBased on SOI-MEMS TechnologyJiao Hailong1, 2*, Chen Deyong1, Wang Junbo1, Zhang Jian1, 2, Cao Mingwei1, 2(1. State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy ofSciences, Beijing 100190, China;2. Graduate University of Chinese Academy of Sciences, Beijing 100080, China)Abstract:This paper presents the design, fabrication, ultra-small capacitance detection and tests of a novel electrostatically driven - capacitively sensed lateral silicon resonator based on SOI-MEMS technology. A new micro resonator structure is proposed, which has a key structure of a beam with two perforated structure stretching from the middle of the beam to each side. This design makes the resonator to be driven by smaller DC voltage bias than other designs with the same overlap area of electrode plates and gap between the two electrode plates. It's fabricated based on SOI wafer with very low resistivity device layer (0.001 to 0.002 ohm•cm), and the process is very simple with only 2 photo mask and 4 key processes. The test results show that the DC voltage bias can be less than 30V, the Vp-p of the AC sine drive voltage is 20mV, and the resonator’s Q-factor is more than 11800 with its resonant frequency 52261.99 Hz in vacuum (0.1—1 Pa).Keywords: MEMS; resonator; electrostatic drive; capacitive sense; SOI基于SOI-MEMS技术的静电驱动-电容检测硅谐振器焦海龙1, 2, 陈德勇1, 王军波1, 张健1, 2,曹明威1, 2(1.中国科学院电子学研究所，传感技术国家重点实验室北方基地，北京100190；2.中国科学院研究生院，北京100080)摘要：提出一种基于SOI-MEMS技术的静电驱动-电容敏感检测的横向硅谐振器，对其进行设计优化、计算仿真、MEMS 工艺加工制作实现、微弱电容检测及开环测试。
SOI电路研究进展进展
SOI抗辐照电路研究进展贺威中国科学院上海微系统与信息技术研究所摘要：本文简要介绍了SOI器件的抗辐照特性，包括其单粒子事件（SEU）和剂量率效应。
综述了国内外SOI抗辐照电路研究的新进展，并对SOI抗辐照电路将来的发展方向作出预测。
关键词：绝缘层上的硅（SOI）、单粒子事件（SEU）、剂量率效应、辐照一、引言SOI是英文Silicon On Insulator 的缩写,指的是绝缘层上的硅。
SOI 技术是指在绝缘层上形成一层具有一定厚度的单晶半导体硅薄膜的材料制备技术。
SOI 材料可实现完全的介质隔离,与有P - N 结隔离的体硅相比,具有无闩锁、高速率、低功耗、集成度高、耐高温等特点,在便携式电子产品、航天、卫星通信等领域均受到普遍重视,被称为“21 世纪的微电子技术”。
美、日、俄、欧及我国都正在大力开展多途径的SOI 技术的研究工作,已取得多项研究成果,并形成了相当的工业生产规模。
SOI电路和器件的一个主要应用是空间及军事电子领域，这主要归功于埋氧的存在使得SOI技术具有了抗瞬时辐射效应的能力。
目前SIMOX存储器电路具有SEU 失效率为10-9/位.天并且在1011rad(si)/s的剂量率辐照下仍然能保持电路功能。
这些数字表明，与体硅电路相比，SOI电路的抗辐照强度提高了100倍。
二、Soi抗辐照特性介绍由于SOI技术具有抗瞬时辐射效应的能力，当前SOI电路和器件的主要应用是空间及军事电子领域。
辐照对电子器件的影响取决于器件所遭受的辐射种类（中子、重粒子以及电磁辐射），与双极器件不同，MOSFET对中子辐射并不敏感。
MOS器件对单粒子事件（SEU）、γ 辐射、总剂量辐射比较敏感。
2.1 单粒子事件（SEU）当一个载能粒子入射到器件中时，就会引起单粒子事件（SEU）失效。
这种粒子入射到一个反偏的P-N结耗尽区及下面的体硅区时，沿着粒子运行的轨迹硅原子被电离，产生电子空穴对。
沿这个轨迹附近P-N结耗尽层发生短时塌陷并且使耗尽层电场的等位面变形，耗尽层变形区又称为“漏斗”。
静电放电次数与半导体器件潜在性失效的关系
静电放电次数与半导体器件潜在性失效的关系第27卷第6期2007年11月河Journalof北大Hebei学(自然科学版University(NaturalScienceV o1.27No.6Nov.2007静电放电次数与半导体器件潜在性失效的关系杨洁,刘尚合,刘红兵2,祁树锋(1.军械工程学院静电与电磁防护研究所,河北石家庄050003;2.中国电子科技集团公司第十三研究所,河北石家庄050000)摘要:为研究硅双极晶体管中由ESD注入引起的潜在性失效与放电次数间的关系,对微波低噪声小功率硅双极器件进行了同一电压不同次数的人体模型ESD注入实验.注入电压为1.50kV.注入管脚为器件对ESD最敏感的端对.器件分组注入不同次数的ESD后,将注入和未注入过ESD的器件同时进行加速寿命实验,通过比较各组器件损伤率的大小来反映器件使用寿命的变化.经统计分析与计算发现:开始时,随放电次数的增加,器件出现潜在性失效的概率增大,当概率达到一定极限值后,又会随放电次数的增大而减小,说明ESD的注入不仅可能在部分硅器件内部造成潜在性失效,也可能提高另外一部分器件的可靠性.关键词:硅双极晶体管;静电放电;潜在性失效;注人次数;微波低噪声小功率;加速寿命实验中图分类号:O441文献标识码:A文章编号:1000—1565(2007)06—0620—05 RelationshipBetweenESDInjectedTimesandLatentDamageinSemi.conductorTransistorsY ANGdie,LIUShang.he,LIUHong.bing,QIShu.feng(1.InstituteofElectrostaticandElectromagneticProtection,Mechanical EngineeringCollege,Shijiazhuang050003,China;2.ChinaElectronicsTechnologyGroup Corporationthe13thResearchInstitute,Shijiazhuang050000,China)Abstract:Currentlylatentdamagesofelectronicdeviceswerewidelydiscussed.Inordertore searchthere—lationshipbetweenESDinjectedtimesandlatentdamageinsilicondipoletransistors,HBME SDimpulseswereinjectedintotheirmostsensitiveportstoESD.High—frequencylow—noisesmall—powerSilicondynatrontransis—tors2SC3356wereselectedandgrouped.Thesameinjectedvoltagewas1.50kV,whichwascl osetoitsthresh-old,buteachgroupwasinjectedwithdifferenttimes.Afterinjection,alltransistors,whichwer einjectedornorinjected,werecarriedontheacceleratedlifetestsatthesametime.Bystatistics,analysesandca lculations,it couldbefoundthatthelatentdamageratesincreasedwiththeESDinjectedtimesincreasingun tilitwasuptoacertainvalue,afterthatthedamageratesdecreasedwithESDinjectedtimesincreasing.Soitco uldbeconcluded thatESDinjectionmightnotonlycauselatentdamagesinsidedynatrons,butalsoenhancepart ialtransistors're-liabilities.Keywords:silicondipoletransistor;ESD;latentdamage;injectedtimes;microwavelow—noisesmall—pow-er;acceleratedlifetest收稿日期:2007—08—20基金项目:国家自然科学基金重点资助项目(50237040);国家自然科学基金面上资助项目(60671044)作者简介:杨洁(1980一),女,河北石家庄人,博士研究生,主要从事电磁防护理论与技术方向的研究,noCd)E第6期杨洁等:静电放电次数与半导体器件潜在性失效的关系?621?静电放电(ElectrostaticDischarge,ESD)可以在微电子器件内部造成3种不同模式的损伤:硬损伤,软损伤和潜在性损伤(使半导体器件产生潜在性失效)_l0.据报道,每年由于ESD可造成电子行业数百亿的损失,而由潜在性失效造成的损失约占其总损失的90%_4.因此研究微电子器件的ESD潜在性失效问题具有重要的现实意义和实际应用价值.所谓ESD潜在性失效是指由ESD在器件内部造成某些轻微的,不易察觉的损伤,此时器件的各项常规参数无明显变化,器件功能仍然满足指标要求,但其内部损伤的存在将导致器件可靠性下降,使器件的使用寿命缩短,或者一个本来不会使器件失效的电脉冲作用却使其失效_5j.为了深入研究微电子器件的ESD潜在性失效问题,首先要了解潜在性失效是如何形成的,影响它形成的因素有哪些.ESD潜在性失效的形成有可能是由于接近阈值的ESD引起,也可能是由于多次ESD的积累造成.也就是说,此类损伤的形成不仅与ESD的作用强度有关,而且与ESD的作用次数也有关系.目前,MOS器件和GaAs微波器件的潜在性失效研究报道较多_7J,而对双极型器件的研究较少.本课题结合工程背景对微波低噪声硅双极型器件进行了ESD潜在性失效与ESD放电次数的关系研究.实验方法与实验结果1.1实验方法实验中选取通用的NPN硅外延晶体管放大器2SC3356(日本生产)为受试样本.它是一种微波低噪声小功率晶体管,特征频率为7.0GHz,额定功率为200mw,属静电敏感器件_9.此器件体积小,管脚短,因此实验中将其焊接于衬板之上以便于测量.实验采用ESD人体模型(HBM,1500Q,100pF)进行直接注入,模拟器选择ESS200AX静电放电模拟器.由于此模拟器并非专用于HBMESD的模拟,为了使短路输出波形符合标准_111]要求,改进电路如图1所示.将实验样品分组注入,同一电压进行不同次数的ESD.图1ItBMESD注入电路框Fig.1HBMESD-iectedtesdiagran选取3组2SC3356器件,各有10只,10只,5只,分别注入ESD3次,6次和9次.放电电压为1.50kV(阈值电压为1.60kV),放电间隔为1.05s,不同次数的ESD均按C+B一进行注入_1一].随后与未注入ESD的10只器件一起进行功耗为500mw(10V×50mA)的加速寿命实验,通过研究器件寿命的变化来判断潜在性失效的存在.ESD注入前后及加速寿命实验的89,159,241,391,605h时,分别测量各器件的放大倍数hFE(测试条件:5V/1ma)和EB结反向漏电流JEBo(测试条件:VEB=1.5V,Jc=0)【,.依据hFE或IEBO~变化来判断器件损伤与否.定义]2FE与EB()减小的量值为AhFIE,△EBo.由于△EB0时正时负,为了便于比较对它取绝对值,记为I△JEBoI.每组样品中损伤器件的个数与该组器件总数之比为各组器件的损伤率,记作.未注入ESD的1组器件损伤率记为珈,注入3次ESD的一组器件损伤率记为仍,以此类推,注入6次的记为76,注入9次的记为79.在进行加速寿命实验前,注入过ESD的器件的电参数经测量仍然全部合格(即仍=r/6r/9=r/0=0).统计加速寿命实验中每组器件在各时段的7,若存在73>j7o或76>7o或9>7o,则说明ESD使器件内部微观机制发生改变,也就是说,虽然ESD的注入没有导致器件损伤,但是却使部分器件的寿命减短,从而证实ESD可在器件内部造成潜在性失效.1.2实验结果1.2.1hFE和JEBo对器件损伤灵敏度的比较实验过程中hFE和JEBo均有一定的变化,但当器件已经由AhFE>30%判断为损伤时,其JEBo始终保持在30nA左右,并未超过既定的损伤条件(IEBO>1A)[.统计每个器件JEBo的变化率,其与器件损伤的关622?河北大学(自然科学版)系如表1所示,数据显示:有时i△JEBoi达到51.1%器件仍未出现损伤,而有时l△JEB(】l仅为9.3%时器件就已经损伤,从而发现l△JER()l与器件损伤的关系不存在特定的规律.由上述结果可得:不宜采用l△JEBol来判断器件损伤.为了进一步比较AhFE和l△J瞰l对器件损伤的灵敏度,统计出现损伤(损伤判据为AhFE>30%)器件的hvE和JEBO最小变化率.以未注入ESD的1组器件为例,图2显示了该组中损伤器件hFE和JEB0变化率的对比,可明显看出:器件出现损伤时hFE变化率>JEBo.注入3次与注入6次的器件出现损伤时,参数对比结果仍然是hr'E变化率>JEH(),这里不再一一详述.而注入9次的一组器件由于未出现损伤,无法对其参数变化进行计算.总而言之,损伤器件的h最小变化率始终大于J的最小变化率,也就是说,h对器件损伤的灵敏度要高于JBo.因此,本实验采用Ah来判断器件损伤与否,讨论放电次数与潜在性失效的关系.表1每个器件I&IEBOI与损伤的关系"lPab.1Relationshipbetweeneachtransistor'SlAJEBI)landdamage△IEB01器件损伤与否9.3%16.4%～18.3%19.4%19.9%20.3%20.5%21.O%～24.O%25.3%26.9%～3O.0%30.4%51.1%损伤未损伤未损伤损伤未损伤损伤未损伤损伤未损伤损伤未损伤\祷图2未注入ESD器件损伤时参数变化率比较Fig.2Comparisonofparameterschangeswhilenn-injectedtransistorsweredamaged表2加速寿命实验中各组器件的损伤率口Tab.2EachgroupDamagerate,,intheacceleratedlifetest1.2.2放电次数与损伤率及潜在性失效的关系选取AhFE>30%作为判断器件完全损伤的标准.叩随加速寿命实验时间的变化如表2所示,观察发现:在加速寿命实验进行到159h之后,各组器件的叩不再变化,将此时的叩与放电次数进行曲线拟合后得图3,可明显看出:开始时叩随放电次数的增加而增大,当达到一定数值后,叩又会随放电次数的增大而减小,直至减小到0为止.拟合曲线方程为叩=0.0012z.一0.0222x.+0,0899x+10.(1)横轴表示放电次数,若忽略作为放电次数必须为整数的条件,根据方程(1)计算可得:当z=2.52时,取最大值,约为20.22%;考虑实际情况中不会出现负值,当=8.16时,叩取最小值,约为0;而当=5.86时,==10%.将z进位取整后与实验结果相对照,二者基本一致,同时拟合方程的相关系数也第6期杨洁等:静电放电次数与半导体器件潜在性失效的关系?623?约为1,说明方程(1)的拟合精度较高,可以用其来反映此类器件ESD放电次数与的关系通过图3,可以看出经过159h的加速寿命实验,ESD注人次数小于6次的样本都会出现>10%的损伤率(即超过叼0),这说明经过小于6次的ESD注入这些器件中已存在潜在性的微观损伤,在使用过程中可能出现潜在性失效.另一方面,同样由图3可得:经过159h加速寿命实验后ESD注人次数大于6次的样本损伤率始终<10%.这说明大于6次的ESD注入,不但没有导致潜在性失效的出现,还使器件内部的某些缺陷由于ESD的作用而有所改善,延长了器件的寿命.观察当注人次数达到9次后刁始终保持为0,由此分析发现,类似于热退火过程,在半导体器件制备工艺中可增加一个多次ESD注入过程来提高器件可靠性.2微观机制分析369ESD放电次数图3加速寿命实验进行到159h之后ESD放电次数与器件损伤率,,的关系Fig.3RelationshipbetweenESDinjectedtimesanddamagerate,,whiletheacceleratedlifetesthadcarriedonfor159hun-injectedtransistorsweredamaged静电放电可形成瞬时大电流,且脉冲上升时间只有几个到十几个纳秒,这时间远小于器件的散热时间常数叫j.当ESD通过小面积的p-n结时,能够产生很大的瞬时功率密度,从而使局部结温达到甚至超过硅的本征温度(1415℃)形成局部过热,导致局部产生热斑,使器件性能下降卜j.在随后的加速寿命实验中,器件的p-n结处于高热状态,热斑处的电流密度显着增大,热斑处的温度急剧上升,当温度达到半导体材料的熔点,热斑融化导致断路或短路,使得器件完全失效.然而,微波低噪声器件结深较浅,结面积也小,本身结构中的很多部分都易受到ESD的作用而发生改变.譬如:它的表面态本身就不稳定,受到ESD的作用就更容易发生改变.表面态的变化可以导致器件可靠性下降,同样也可能提高器件的可靠性.由它引起的hFE小范围变化(约在10左右)会随时间而自我恢复.另外,器件内部表面晶格由于ESD的作用也会导致不同效果.一方面,ESD的注入使表面晶格某点过热熔融,在随后的加速寿命实验中由于该处电流集中导致过热熔断,从而使性能下降,但由于晶格熔融再结晶时的不可预测性,热效应也可能使此类损伤因晶格的再次熔融与恰好的规则结晶而自行恢复;另一方面,多次ESD的注入使p-n结表面晶格多次经历熔融结晶的重组过程,使本来分布不均匀的晶格分布均匀,同时还可使晶格结构中的杂质离子由于场的激励作用到达不易影响p-n结特性的部位,从而起到了退火的作用,增强器件的可靠性,延长使用寿命.3结论1)接近阈值电压(1.50kV)的ESD注入可在微波低噪声小功率硅晶体管2SC3356内部造成潜在性失效.^FE的变化对器件损伤的灵敏度要高于B0.2)对于2SC3356来说,同一电压的ESD,随注人次数增大器件损伤率叼存在一个最大值.一旦刁达到最大值,它将随注人次数的增大而减小,直至为0.通过比较加速寿命实验中各时段未注入与注入ESD器件的,可以得出结论:当ESD放电次数小于6次时,会在部分器件内部造成潜在性失效;而当ESD放电次数为3次时,出现潜在性失效器件占器件总数的比率最高.3)从实验结果看出,整个加速寿命实验中刁始终为0,从而发现:对2SC3356来说,9次ESD的注入可以延长器件寿命,改善其内部的部分缺陷.于是得出推论:对半导体器件来说,可在其制备工艺中增加一个多624?河北大学(自然科学版)2007矩次ESD注入的老练程序,以提高器件的可靠性.这一点具有很大的工程实用意义,有待继续实验来进行更深一步的研究.参考文献:[I]刘尚合,魏光辉,刘直承,等.静电放电理论与防护[M].北京:兵器工业出版社,1999.[2]刘尚合.静电放电及危害防护[M].北京:北京邮电大学出版社,2004.[3]庄弈琪.微电子器件应用可靠性技术[M].北京:电子工业出版社,1996.[4]邓永孝.半导体器件失效分析[M].北京:宇航出版社,1987.[5]STENHELLSTR6M.ESD-ThescourgeofElectronics[M].Springer.VerlagBerlinHeid 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InternationalSymposiumonTestandMeasurement,Dalian,China,June1—4,2005,3:2060—2062.[13]杨洁,王长河,刘尚合.微波低噪声晶体管电磁脉冲敏感端对研究[J].强激光与粒子束,2007,O1:99—102.[14]来萍,刘发.探索用静态小电流参数表征CMOS电路的静电放电(ESD)潜在损伤[z].第八界全国可靠性物理学术讨论会,北京.1999.[15]高光渤,李学信.半导体器件可靠性物理[M].北京:科学出版社,1987:466—472.[16]涂延林,马峰,黄能斌.电子工业静电防护技术[M].西安:陕西科学技术出版社,1994:29—39.(责任编辑:梁俊红)。
低噪声硅微陀螺敏感电容电荷读出电路设计
低噪声硅微陀螺敏感电容电荷读出电路设计卢月娟;徐大诚;郭述文【期刊名称】《传感器与微系统》【年(卷),期】2017(036)001【摘要】硅微陀螺敏感电容电荷读出电路性能的优劣直接决定着陀螺仪测量精度.通过对敏感电容读出电路的建模分析,采用差分调制技术实现了低噪声信号输出,从电路组成、参数设置、PCB布局布线等多方面综合考虑,优化设计了能抑制低频噪声以及高灵敏度电荷读出电路.实验结果表明:该电路输出噪声为-116.24 dBV/√Hz,敏感电容检测分辨率可达1.16 ×10-19 F√Hz.%Measurement precision of silicon micro-gyroscope is determined by sensitive capacitor readout circuit.Through modeling analysis on sensive capacitor readout circuit,use differential modulation technology to realize low noise signal output.A charge readout circuit which can suppress low frequency noise and high sensitivity is optimally designed in parameter and PCB.Esperimnental results indicate that output noise of the circuit is -116.24 dBV/√Hz and sensitive capacitor detecting resolution is 1.16 × 10-19F/√Hz.【总页数】4页(P105-107,114)【作者】卢月娟;徐大诚;郭述文【作者单位】苏州大学微纳传感技术研究中心,江苏苏州215006;苏州大学微纳传感技术研究中心,江苏苏州215006;苏州大学微纳传感技术研究中心,江苏苏州215006【正文语种】中文【中图分类】TP212【相关文献】1.用于CZT探测器信号读出的低噪声电荷灵敏前放A250 [J], 邓智;朱维彬;李元景;张岚;刘以农2.一种用于电容型体硅微陀螺的低噪声读出电路芯片 [J], 尹韬;杨海钢;张翀;吴其松;焦继伟;宓斌玮3.低噪声线性霍尔传感器读出电路设计 [J], 张小燕;魏榕山D低噪声读出电路设计 [J], 狄腊梅; 刘宏; 张志勇5.有机械耦合的电容式硅微陀螺敏感信号读取研究 [J], 陈建元因版权原因，仅展示原文概要，查看原文内容请购买。
MEMS微陀螺仪振动分析---优秀毕业论文参考文献可复制黏贴
作者签名： 日 期：
南京航空航天大学硕士学位论文
摘要
随着人类对 MEMS 微陀螺仪的探索日益深入，作为一类新兴发展的惯性传感器，它的发展 和应用正受到广泛关注和重视。本文针对微机械振动陀螺仪的机-电耦合振动问题进行研究，主 要内容如下。
首先，分析了一硅微机械振动陀螺仪的结构与工作机理，将其简化成质量-弹簧-阻尼器力 学模型，建立振动微分方程。通过驱动模态和感应模态的运动，揭示了微陀螺仪设计过程中模 态匹配的重要性。然后，分析了由于加工非理想性产生的不等弹性、阻尼不对称和质量不平衡 产生误差的信号，建立了机械耦合误差信号和数学模型，并定量分析了 z 轴硅微陀螺仪的机械 耦合误差信号。结果表明，机械耦合误差信号包含了正交耦合误差与有用信号同相位的误差信 号，其中正交耦合误差为主要误差信号，且主要由不等弹性产生。
中图分类号：O327 学科分类号：080104
论文编号：1028701 12-S046
硕士学位论文
MEMS 指导教师
徐寅 工程力学 振动控制与振动利用 金栋平 教授
南京航空航天大学
研究生院 航空宇航学院
二О一一年十二月
Nanjing University of Aeronautics and Astronautics The Graduate School
最后，为解决该设计可能出现的机电耦合缺陷，本文在驱动框的外侧设计了检测电容和静 电力反馈电容，以实现驱动闭环控制，提高了输出精度和检测灵敏度。
关键词：硅微陀螺仪，耦合误差，机-电耦合，非线性振动，闭环反馈控制
本文工作在机械结构力学及控制国家重点实验室完成。
I
MEMS 微陀螺仪振动分析
ABSTRACT
基于SOI的MEMS高温压阻式压力传感器
第58卷第4期 2021年4月撳纳电子技术Micronanoelectronic TechnologyVol.58 No.4April 2021t)M E M S与待感眾$DOI：10. 13250/ki.wndz.2021. 04. 007基于SO I的MEMS高温压阻式压力传感器单存良a’b，梁庭a’b，王文涛a’b，雷程a’b，薛胜方a’b，刘瑞芳a’b，李志强a’b(中北大学仪器与电子学院a.仪器科学与动态测试教育部重点实验室；b.动态测试技术山西省重点实验室，太原 030051)摘要：基于高温环境下压力实时监测的广泛需求，设计并制备了一种最大量程为1.5 MPa的绝缘体 上硅（SOI)压阻式压力传感器。
根据压阻效应原理和薄板变形理论，完成了传感器力学结构和电 学性能的设计，采用微电子机械系统（MEMS)加工工艺完成了敏感芯片的制备，并使用了一种可 耐300 °C高温的封装技术。
实验中采用了常温压力测试平台和压力-温度复合测试平台进行测试，测试结果表明，封装后的传感器在常温环境下具有良好的非线性误差、迟滞性和重复性，其灵 敏度可达到0.082 8 mV/kPa,同时在300 °C高温环境中其灵敏度仍可达0.063 8 mV/kPa。
关键词：高温压力传感器；微电子机械系统（MEMS);压阻效应；灵敏度；倒装封装中图分类号：TP212; TH703 文献标识码：A文章编号：1671-4776 (2021) ()4_0325-(_)7MEMS High Temperature PiezoresistivePressure Sensor Based on SOIShan Cunliang*,b,Liang Ting*'b,Wang Wentao8,b,Lei Chenga-b,Xue Shengfang*'b,Liu Ruifang a,b,Li Zhiqianga,b(a. Ke y Laboratory o f Instrum entation Science and D ynam ic M easurement o f M inistry o f Education；b. Sh a n xi Provincial K ey Laboratory o f D ynam ic Testing T echnology，School o f Instrum ent andElectronics, North U niversity o f China , Taiyuan030051, C hina)Abstract：Based on the wide demand for real-time pressure monitoring in high temperature environment,a piezoresistive pressure sensor with the maximum range of 1. 5 MPa based on silicon-on-insulator (SOI)was designed and prepared.According to the principle of piezoresistive effect and the theory of thin plate deformation,the mechanical structure and electrical properties of the sensor were designed.The sensitive chip was prepared by the micro-electromechanical system (MEMS)processing technology,and a packaging technology to withstand high temperature of300 °C was used.A room temperature pressure test platform and a pressure-temperature composite test platform were used for testing in the experiment.The test results show that the encapsulated sensor has good nonlinear error,hysteresis and repeatability at room temperature,and收稿日期：2020-11-03基金项目：山西省重点研发计划项目（201903D121123);山西省自然科学基金项目（201801D121157, 201801D221203)通信作者：梁庭，E-mail:********************.cn325徵M电子技术its sensitivity can reach0. 082 8 mV/kPa,while its sensitivity can still reach0. 063 8 mV/kPa at 300 °C high temperature.Keywords: high temperature pressure sensor；micro-electromechanical system(MEMS)；pie-zoresistive effect；sensitivity；flip chip packageEEACC： 7230M； 2575Fo引百高温恶劣环境下，压力的原位测量需求广泛存 在于各领域中，如汽车和飞机发动机舱内部的高温 压力测量控制、航空航天飞行器外表面高温压力测 量等。
Si SOI微剂量探测器电荷收集特性数值模拟
Si SOI微剂量探测器电荷收集特性数值模拟唐杜;刘书焕;李永宏;贺朝会【期刊名称】《太赫兹科学与电子信息学报》【年(卷),期】2012(010)005【摘要】采用数值模拟软件TCAD对影响绝缘体上硅(SOI) PIN微剂量探测器灵敏区电荷收集特性的主要因素进行了模拟与分析.分析了3 MeVα粒子在PIN探测器内沉积能量产生的瞬时电流随探测器偏置电压(10 V至50 V)和掺杂浓度、粒子入射方向的变化.模拟结果表明,随着反偏电压的增大,载流子复合效应降低,瞬态电流增加；当n+区域反偏电压为10V时,由α粒子入射产生的空间电荷在1 ns内几乎全部被收集,电荷收集效率接近100％；辐射产生的瞬时电流随探测器各端掺杂浓度的增大而减小.%2D simulation of the main influence factors on the charge collection characteristics of Silicon On Insulator(SOI) PIN microdosimeter was performed with TCAD software. The transient current in the microdosimeter induced by 3 MeV alpha particle was calculated at different applied voltages(from 10 V to 50 V), doping concentrations and alpha incident directions. The simulation results show that the transient current increases with the increase of reverse bias voltage due to the decrease of the carrier recombination effect; and the space charges induced by alpha particle are almost collected in 1 ns with 10 V applied to the n+ region at the charge collection efficiency nearly 100%; and the transient current decrease when the doping concentration of each region increases.【总页数】5页(P616-620)【作者】唐杜;刘书焕;李永宏;贺朝会【作者单位】西安交通大学核科学技术学院,陕西西安710049;西安交通大学核科学技术学院,陕西西安710049;西安交通大学核科学技术学院,陕西西安710049;西安交通大学核科学技术学院,陕西西安710049【正文语种】中文【中图分类】TN34;TL814【相关文献】1.同轴高纯锗探测器探测效率的MCNP模拟与电荷收集时间的计算 [J], 梁爽;何高魁;郝晓勇2.4H-SiC肖特基二极管的电荷收集特性 [J], 吴健;雷家荣;蒋勇;陈雨;荣茹;范晓强3.平面型CdZnTe探测器电荷收集效率对能谱测量的影响 [J], 李杨;罗文芸;贾晓斌;张家磊;王林军4.CVD金刚石薄膜探测器对γ射线响应的电荷收集效率测量方法 [J], 雷岚;欧阳晓平;夏良斌;谭新建;张小东5.SOI硅微剂量探测器对中子和伽马辐射场线能谱测量的GEANT4模拟研究 [J], 雷鸣;刘书焕;宗鹏飞;刘兵因版权原因，仅展示原文概要，查看原文内容请购买。
新型部分耗尽SOI器件体接触结构
新型部分耗尽SOI器件体接触结构宋文斌,毕津顺,韩郑生(中国科学院微电子研究所,北京100029)摘要:提出了一种部分耗尽S OI MOSFET体接触结构,该方法利用局部SI MOX技术在晶体管的源、漏下方形成薄氧化层,采用源漏浅结扩散,形成体接触的侧面引出,适当加大了Si膜厚度来减小体引出电阻。
利用ISE2T C AD三维器件模拟结果表明,该结构具有较小的体引出电阻和体寄生电容、体引出电阻随器件宽度的增加而减小、没有背栅效应。
而且,该结构可以在不增加寄生电容为代价的前提下,通过适当的增加Si膜厚度的方法减小体引出电阻,从而更有效地抑制了浮体效应。
关键词:绝缘体上硅;浮体效应;体接触;寄生电容;体电阻中图分类号:T N386 文献标识码:A 文章编号:10032353X(2008)1120968204N ovel Body2Contact Structure Technology for P artiallyDepleted SOI MOSFETS ong Wenbin,Bi Jinshun,Han Zhengsheng(Institute o f Microelectronics o f Chinese Academy o f Sciences,Beijing100029,China)Abstract:A novel body contact technique for partially depleted S OI MOSFET was proposed.T w o thin buried2oxide layers under s ource/drain on a S OI chip were formed near the Si surface with low dose and low energy local SI MOX technology.And a body2under2s ource structure is easy to be formed because of the shallow s ource/drain junction depth in this structure,which has a thick Si film.From ISE2T C AD32D simulation results,this structure has little body resistance and body parasitic capacitance and has no back2gate effect.The body resistance decreases as channel width is increasing.Above all,this structure can reduce body resistance to suppress floating body2effect significantly by increasing Si film thickness,without affecting the parasitic capacitance.K ey w ords:S OI(Si on insulator);floating body effect;body contact;parasitic capacitance;body resistanceEEACC:2570D0 引言S OI技术带来器件和电路性能提高的同时也不可避免地带来了不利的影响,其中最大的问题在于部分耗尽S OI器件的浮体效应。
SOI硅微剂量计物理结构设计中的电荷收集及能量沉积特性模拟研究
㊀第43卷㊀第5期2023年㊀9月㊀辐㊀射㊀防㊀护Radiation㊀ProtectionVol.43㊀No.5㊀㊀Sep.2023㊃辐射防护监测㊃SOI 硅微剂量计物理结构设计中的电荷收集及能量沉积特性模拟研究闫学文1,2,靳海晶1,2,李㊀华1,2,李德源1,2,乔㊀霈1,2,牛蒙青1,2(1.中国辐射防护研究院,太原030006;2.核药研发转化与精准防护山西省重点实验室,太原030006)㊀摘㊀要:采用TCAD 软件和蒙特卡罗方法对SOI 硅微剂量计的电荷收集特性与能量沉积特性进行了研究㊂分析了电场分布随探测单元形状㊁尺寸㊁电极注入深度㊁入射粒子种类和能量的变化情况以及微剂量谱随探测单元形状以及聚甲基丙烯酸甲酯(PMMA )转换层厚度的变化情况㊂模拟结果表明,在10μm 的范围内,硅探测单元采用圆柱型或立方体结构对电荷收集效率和能量沉积的影响均很小,探测单元高度越高㊁半径越小,电荷收集效率越高,PMMA 转换层的厚度对微剂量谱有一定的影响,随着PMMA 厚度增加,中子和γ射线与PMMA 作用产生的次级粒子被阻止在硅灵敏区内的份额增加,导致了微剂量谱峰值的增高㊂关键词:SOI 硅微剂量计;电荷收集;能量沉积;微剂量谱中图分类号:TL8文献标识码:A㊀㊀收稿日期:2023-02-16基金项目:山西省应用基础研究计划(20210302124486)㊂作者简介:闫学文(1990 ),男,2014年毕业于南华大学核技术专业,2017年毕业于兰州大学核技术及应用专业,获硕士学位,助理研究员㊂E -mail:yanxw1228@通信作者:李华㊂E -mail:lihua_7559@㊀㊀放射治疗是癌症治疗最常用的手段,常规X㊁γ射线放疗在人体组织内的剂量分布不理想,在杀死癌细胞的同时,周围健康组织也受到了较大损伤,造成明显副效应乃至一些并发症㊂与常规X㊁γ射线相比,质子㊁重离子以及中子等高传能线密度(linear energy transfer,LET)粒子具有倒转的深度剂量分布及Bragg 峰附近相对较高的生物效应,通过束流调制㊁适形调强等技术选择性地将剂量集中分布在目标靶区,能够减少在周围正常组织中的能量沉积,从而降低放疗副作用[1-4]㊂在评估高LET 粒子辐射对人体组织的损伤作用时,除了从宏观层面考虑离子束在目标靶区内的吸收剂量外,还需要考虑在微尺度空间离子随机作用产生的能量沉积,即微剂量分布,以评价其相对生物效应㊂微剂量测量对揭示辐射生物效应的微观本质至关重要㊂想要了解辐射对细胞的影响,必须在与细胞结构相当的尺度下对沉积能量的分布情况进行研究㊂Bradley 等人[5-6]在1998年设计开发了一种能够真实模拟细胞尺度的SOI 硅微剂量计,用于微剂量的精确测量㊂但由于微纳加工技术以及探测效率的限制,至今仍未形成特别实用的产品㊂因此,本文就SOI 硅微剂量计的电荷收集及能量沉积特性进行模拟研究,以期明确微剂量计物理结构设计的影响因素,有助于后续SOI 硅微剂量计的设计研发㊂1㊀SOI 硅微剂量计的结构及工作原理㊀㊀SOI 硅微剂量计是通过将硅半导体蚀刻成细胞大小的探测单元来记录辐射粒子在其中的能量转移和沉积,具有空间分辨率高㊁响应快㊁输出信号强并且能从物理层面真实模拟细胞尺度的突出优势[7-9]㊂SOI 硅微剂量计大致包括5个部分:Si灵敏区㊁SiO 2埋氧层㊁Si 基底以及n +㊁p +电极和聚甲基丙烯酸甲酯(polymethyl methacrylate,PMMA)转换层,具体结构如图1所示㊂具体工作原理[10]:当载能粒子入射到剂量计的灵敏区(图1圆柱型Si 灵敏区范围内)时,在灵敏区内沉积能量,电离产生大量电子-空穴对,这些电子-空穴对在外加电场的作用下漂移,最后电子和空穴分别被n +极㊃344㊃㊀辐射防护第43卷㊀第5期和p +极收集,产生瞬时电流,通过对电流信号的读取来获得剂量信息㊂图1㊀SOI 硅微剂量计结构图Fig.1㊀Structure of SOI-Si microdosimeter2㊀电荷收集特性模拟㊀㊀SOI 硅微剂量计是从物理结构出发真实模拟细胞尺寸的半导体阵列探测器,目的是获取每个细胞内部的能量沉积,而对能量沉积的探测需要转化为对电荷的收集㊂因此,SOI 硅微剂量计的物理结构设计中需要避免相邻硅灵敏区之间的电荷共享,对微剂量计的电荷收集特性进行模拟研究对其物理结构的设计具有极其重要的指导意义㊂2.1㊀SOI 硅微剂量计的TCAD 建模㊀㊀如图1所示,利用TCAD (technology computeraided design)软件对圆柱型硅探测单元进行建模㊂由于人体细胞的尺寸大部分是在10μm 甚至小于10μm 的范围内,且目前微纳加工技术能很好地实现10μm 左右的半导体蚀刻工艺,因此初始建模参数如下:硅单元高10μm,直径10μm;埋氧层(SiO 2)厚度为2μm,硅衬底厚度为400μm,埋氧层和衬底宽度均为20μm;中间n +电极(阳极)注入深度2μm,宽度2μm,磷掺杂峰值浓度1ˑ1020cm -3,外圈p +电极(阴极)注入深度1μm,宽度1μm,硼掺杂峰值浓度1ˑ1020cm -3;阴㊁阳Al 电极厚度均为0.2μm,边长均为1μm㊂利用TCAD 软件对SOI 硅微剂量计进行相关电参数的模拟,主要涉及到不同硅探测单元尺寸对应的电场变化㊁电极注入深度不同时对应的电场变化以及重离子入射到灵敏体积内产生的电荷分布等㊂图2所示为圆柱型探测单元n +端加10V 反向偏压时的电场分布,从图2可以看出,电场基本集中分布在硅单元内的n +电极和p +电极之间,在埋氧层及硅衬底部分也有电场分布㊂本文主要目的就是要通过改变物理结构设计减少电荷在硅衬底中的分布,提高硅探测单元对电荷的收集效率㊂图2㊀圆柱型探测单元加10V 反向偏压时的电场分布Fig.2㊀Electric field distribution of cylindricaldetection unit with 10V reverse bias2.2㊀结构形状对电荷收集的影响㊀㊀通过TCAD 软件分别建立了立方体和圆柱型两种形状的硅微剂量计物理模型㊂其中立方体硅探测单元尺寸为10μm ˑ10μm ˑ10μm,圆柱型硅探测单元尺寸为ϕ10μm ˑ10μm,埋氧层㊁硅衬底以及电极注入情况均相同,具体参照图1所示结构㊂对立方体和圆柱型两种结构形状的微剂量计进行了电场空间分布的模拟计算,在n +端加10V反向偏压后得到两种结构形状下同一位置处(图2中显示的距探测单元顶部1μm)电场的具体分布,如图3所示㊂图3㊀立方体和圆柱型n +端加10V 偏压时距顶部1μm 处的电场分布Fig.3㊀Electric field distribution at 1μm from the topof cube and cylinder with 10V bias voltage for n +end㊃444㊃闫学文等:SOI 硅微剂量计物理结构设计中的电荷收集及能量沉积特性模拟研究㊀从图3中可知,直径和边长相同㊁高度相同的圆柱型和立方体硅探测单元在10V 反向偏压的情况下,电场分布几乎完全一致㊂这说明备选的两种初始结构对电场的影响几乎可以忽略㊂因此,基于SOI 硅基微剂量计的结构设计中采用圆柱或立方体均可,对电荷收集影响甚微㊂对不同尺寸的圆柱型硅探测单元进行模拟计算㊂保持圆柱型硅探测单元的高度10μm 不变,圆柱型结构半径从2~5μm 逐渐改变,得到如图4所示的电场分布;保持圆柱型硅探测单元的半径5μm 不变,圆柱型结构高度从4~10μm 逐渐改变,得到如图5所示的电场分布㊂图4㊀圆柱型探测单元半径变化时的电场分布Fig.4㊀Electric field distribution of cylindrical detectionelements with varying radiusdimension图5㊀圆柱型探测单元高度变化时的电场分布Fig.5㊀Electric field distribution of cylindricaldetection elements with varying height dimension从图4可知,当圆柱型硅探测单元高度保持10μm 不变,半径从5μm 逐渐减小到2μm 时,由于电压不变,距离缩短,导致了n +端和p +端之间形成的电场强度逐渐升高,说明半径越小对电荷的收集效率越高㊂从图5可知,当圆柱型硅探测单元半径保持5μm 不变,高度从10μm 逐渐减小到4μm 时,n +端和p +端之间的电场变化趋势在8~10μm 之间较为平缓,当高度减小到6μm 时,电场开始发生变化,直到减小到4μm 时发生了剧烈变化,在n +的远端发生了骤减㊂但由于高度减小㊁半径不变等效于相邻探测单元之间的物理距离减小,因此在p +往外的位置电场强度逐渐升高,这会降低硅探测单元的电荷收集率㊂因此,说明半径为5μm的圆柱型硅探测单元对应8~10μm 的高度时对电荷收集是有利的㊂综上所述,在10μm 的尺寸范围内,硅探测单元采用圆柱型或立方体结构对电荷收集效率的影响不大,探测单元高度越高㊁半径越小,电荷收集效率越高㊂应综合考虑现有微纳加工技术的成熟度选择硅探测单元的尺寸,尽量做到半径小㊁高度高㊂2.3㊀电极注入深度对电荷收集的影响㊀㊀电极注入深度的不同也可能影响n +端和p +端之间形成的电场分布㊂因此,仿真模拟了硅探测单元电极注入深度不同时的电场分布情况,结果如图6所示㊂仿真采用了圆柱型硅探测单元,结构尺寸为ϕ10μm ˑ10μm,埋氧层㊁硅衬底保持如图1所示结构不变,电极注入深度从2~10μm 逐渐改变㊂图6㊀电极注入深度变化时的电场分布Fig.6㊀Electric field distribution of cylindrical detectionelements with varying depth of electrode injection㊃544㊃㊀辐射防护第43卷㊀第5期从图6中可看出,电极注入的深度大于6μm时,n +端和p +端之间的电场变化基本趋于缓和,电极注入深度小于6μm 时,电场变化相对较大㊂但是,当电极注入深度小于8μm 时,由于相邻探测单元p +电极和p +电极之间未建立完全物理隔离,p +端向外产生的电场强度随着电极注入深度的减小逐渐升高,这会降低硅探测单元的电荷收集㊂因此,在10μm 的探测单元中,电极注入深度应选择大于8μm 较佳㊂2.4㊀重离子入射灵敏区域的电荷收集状况㊀㊀仿真模拟了3MeV 的α粒子和2MeV 的质子入射到灵敏体积时空间电荷在不同时刻的空间分布情况㊂α粒子和质子分别从n +极和p +极中间的硅灵敏区入射,位置如图7所示箭头方向㊂硅探测单元尺寸为ϕ10μm ˑ10μm 和ϕ20μm ˑ10μm,n +端加10V 偏压,得到的各时间点的电势分布如图7所示㊂图7㊀不同粒子入射到不同灵敏体积后不同时刻的电势分布Fig.7㊀Potential distribution at different time after different particles incident on the sensitive volume㊀㊀从图7中可看出,当硅探测单元直径为10μm时,在粒子入射后约1ns 的时间内,电势基本回归到与入射时的状态一致,说明1ns 的时间内电荷几乎全部被收集㊂而将硅探测单元直径增大到20μm 时,粒子入射1ns 的时刻,由于相邻探测单元对其电荷产生的影响还未完全消失,在p +端外延处还存在一定的电势,此时电荷收集未完成㊂另外,对中子的探测实际上是对中子与物质相互作用后产生的α㊁质子等重离子的探测,以上仿真结果同样适用于中子㊂综上可知,硅探测单㊃644㊃闫学文等:SOI硅微剂量计物理结构设计中的电荷收集及能量沉积特性模拟研究㊀元的半径越小,越有利于在较短的时间内完成电荷收集㊂3㊀能量沉积特性模拟3.1㊀SOI硅微剂量计的蒙特卡罗建模㊀㊀按照设计参数,基于蒙卡方法初步建立了硅探测阵列(11ˑ11)模型,如图8所示,模拟在SOI 晶体上蚀刻出直径9μm,高度9μm的圆柱型探测单元,探测单元之间和顶部均使用PMMA转换层进行填充,圆柱轴心注入n+电极,圆周注入p+电极,上接铝电极后包裹一层SiO2以形成保护层㊂具体如图8所示㊂为显示效果,本文建模图片中硅衬底厚度并非实际建模厚度㊂3.2㊀能量沉积模拟㊀㊀针对圆柱型和立方体两种结构的探测单元,利用中子㊁质子和α粒子轰击硅敏感单元获取其能量沉积情况㊂模拟计算中硅探测单元尺寸:圆㊀㊀㊀㊀㊀图8㊀基于蒙卡的硅探测阵列建模Fig.8㊀Modeling of silicon detectorarray based on Monte Carlo柱型ϕ9μmˑ9μm,立方体9μmˑ9μmˑ9μm,周围用PMMA包裹㊂入射粒子方向垂直于硅探测单元平面,在9μmˑ9μm的范围内均匀入射,中子㊁质子和α粒子的能量均为5MeV㊂图9是α粒子㊁质子和中子入射粒子轰击硅探测单元的能量沉积情况,图中均只显示了探测单元横截面的1/4部分㊂图9㊀入射粒子轰击硅探测单元(圆柱型和立方体)的能量沉积Fig.9㊀Energy deposition of incident particles bombarding silicon detection units(cube and cylinder)㊀㊀由图9可知,中子㊁质子和α粒子轰击探测单元,较大的能量沉积基本发生在硅敏感单元内,在PMMA中的能量沉积明显较少㊂因此,针对能量沉积特性分析,模拟中的硅基微剂量计结构符合实际需求㊂3.3㊀结构形状对微剂量谱的影响为实现设计结构对微剂量的高效测量,对圆柱型和立方体探测单元两种结构进行了60Co 和137Cs源的微剂量谱的仿真模拟,仿真中计算中入射粒子方向垂直于硅探测单元平面,在9μmˑ9μm的范围内均匀入射㊂圆柱型硅探测单元尺寸为ϕ9μmˑ9μm,立方体硅探测单元尺寸为9μmˑ9μmˑ9μm,微剂量谱的仿真结果如图10和图11所示㊂㊃744㊃㊀辐射防护第43卷㊀第5期图10㊀立方体与圆柱型硅探测单元微剂量谱对比(60Co )Fig.10㊀Comparison of microdose spectrum betweencube and cylindrical silicon detector (60Co)图11㊀立方体与圆柱硅探测单元微剂量谱对比(137Cs )Fig.11㊀Comparison of microdose spectrum betweencube and cylindrical silicon detector (137Cs )由图10和图11可知,针对60Co,立方体和圆柱型两种结构下积分面积偏差为1.86%;针对137Cs,立方体和圆柱型两种结构下积分面积偏差为3.79%㊂以上结果充分说明在立方体与圆柱型两种硅探测单元结构下,微剂量谱基本重合,立方体与圆柱型的设计结构在实际应用中均可㊂这与本文2.2节中尺寸为10μm ˑ10μm ˑ10μm 的立方体与ϕ10μm ˑ10μm 的圆柱型结构的电荷收集仿真结果一致㊂3.4㊀PMMA 转换层对微剂量谱的影响㊀㊀PMMA 转换层在SOI 硅微剂量计中的作用是将中子和γ等不带电粒子转换成相应的次级带电粒子,然后这些带电粒子经过SOI 硅灵敏区产生脉冲信号,从而得到相应的线能谱数据[11]㊂因此,PMMA 的厚度对中子和γ等不带电粒子的微剂量测量会产生一定的影响㊂为了得到PMMA 转换层厚度对硅基微剂量计微剂量谱的影响,模拟了60Co 和137Cs 的γ微剂量谱在不同厚度的PMMA 转换层下的变化情况㊂模拟过程中采用圆柱型硅探测单元,尺寸为ϕ9μm ˑ9μm,PMMA 厚度从0.0~5.0mm 逐渐增加,入射粒子方向垂直于硅探测单元平面,在9μm ˑ9μm的范围内均匀入射㊂图12㊀PMMA 转换层厚度对微剂量谱的影响(60Co )Fig.12㊀Effect of PMMA conversion layerthickness on microdose spectrum (60Co)图13㊀PMMA 转换层厚度对微剂量谱的影响(137Cs )Fig.13㊀Effect of PMMA conversion layerthickness on microdose spectrum (137Cs )由图12和图13可知,随着PMMA 厚度的增㊃844㊃闫学文等:SOI 硅微剂量计物理结构设计中的电荷收集及能量沉积特性模拟研究㊀加,SOI 硅微剂量计探测到的60Co 和137Cs 的γ能谱分布变化基本一致,但是谱峰值发生了一定的变化㊂随着转换层厚度的增加,在1~10keV /μm区间呈现出峰位向右偏移且峰值逐渐增高的结果㊂这可能是因为当转换层厚度较小时,γ射线与转换层相互作用产生的次级电子大部分可穿过硅灵敏区,随着厚度增加,部分次级电子被阻止在硅灵敏区的份额逐渐增加,使得相应的峰值增加㊂采用同样尺寸的圆柱型硅探测单元模拟了252Cf 中子微剂量谱,入射粒子方向垂直于硅探测单元平面,在9μm ˑ9μm 范围内均匀入射㊂PMMA 厚度从0.0~3.0mm 逐渐增加,不同转换层厚度下的谱分布如图14所示㊂图14㊀PMMA 转换层厚度对微剂量谱的影响(252Cf )Fig.14㊀Effect of PMMA conversion layerthickness on microdose spectrum (252Cf )㊀㊀由图14可知,随着PMMA 转换层厚度的增加,在10~100keV /μm 区间内谱峰同样发生了右移以及增高,说明中子与转换层相互作用产生的次级质子被阻止在硅灵敏区的份额随着PMMA 厚度的增加而逐渐增加㊂4㊀结论㊀㊀本文采用TCAD 和蒙特卡罗方法分别对SOI 硅微剂量计物理结构设计中的电荷收集特性和能量沉积特性进行了模拟研究,结果表明在10μm 的尺寸内,(1)SOI 硅微剂量计的结构形状对电荷收集和能量沉积的影响均很小;(2)对圆柱型结构进行模拟,探测单元的半径越小㊁高度越高,其电荷收集效率越高,在1ns 的时间内基本能达到100%的电荷收集率;(3)当探测单元高度为10μm 时,电极注入深度达到8μm 对电荷收集更有利;(4)PMMA 转换层厚度的增加将中子和γ射线产生的次级粒子更多地阻止在了硅灵敏区内,导致了微剂量谱的峰值增高㊂以上结论将对SOI 硅微剂量计的物理结构设计起到一定的指导意义㊂参考文献:[1]㊀朱煜和,易忠诚,肖明勇.放射治疗剂量验证的现状及进展[J].生物医学工程学杂志,2013,30(6):1358-1361.ZHU Yuhe,YI Zhongcheng,XIAO Mingyong.Present situation and progress of dose verification in radiotherapy [J ].Journal of Biomedical Engineering,2013,30(6):1358-1361.[2]㊀王文,程梦云,杨琪,等.基于MCNP 源子程序的放射治疗剂量计算验证方法[J].中国医学物理学杂志,2015,32(1):13-16.WANG Wen,CHENG Mengyun,YANG Qi,et al.A dose verification method based on MCNP source subroutine forradiotherapy[J].Chinese Journal of Medical Physics,2015,32(1):13-16.[3]㊀LD Marzi,A Patriarca,N Scher,et al.Exploiting the full potential of proton therapy:An update on the specifics andinnovations towards spatial or temporal optimisation of dose delivery[J].Cancer,2020(24):691-698.[4]㊀Laura De Nardo.Development of a multiple microdosimetric detector based on gem (gas electron multiplier)for hadron-therapy applications[D].Universit degli studi di Padova,2014.[5]㊀Bradley P D,Rosenfeld A B,Zaider M,et al.Solid state microdosimetry[J].Nuclear Instrument and Methods in PhysicsResearch B,2001,184(1-2):135-157.㊃944㊃㊀辐射防护第43卷㊀第5期[6]㊀Anatoly B Rosenfeld.Novel detectors for silicon based microdosimetry,their concepts and applications [J ].Nuclear Instruments and Methods in Physics Research A,2016,809:156-170.[7]㊀Rossi H H,Zaider M.Microdosimetry and its applications[M].London:Springer,1996:1-13.[8]㊀Bradley P D,Rosenfeld A B,Zaider M,et al.Solid state microdosimetry[J].Nuclear Instrument and Methods in PhysicsResearch B,2001,184(1-2):135-157.[9]㊀闫学文,李华,李德源,等.基于SOI 微剂量实验测量技术的研究现状与展望[J].辐射防护,2022,42(1):1-10.YAN Xuewen,LI Hua,LI Deyuan,et al.Research status and prospects of microdose experimental measurement technology based on SOI [J].Radiation Protection,2022,42(1):1-10.[10]㊀唐杜,刘书焕,李永宏,等.Si SOI 微剂量探测器电荷收集特性数值模拟[J].辐射防护,2012,10(5):616-620.TANG Du,LIU Shuhuan,LI Yonghong,et al.Numerical simulation of charge collection characteristics of Si SOI microdosimeter [J].Radiation Protection,2012,10(5):616-620.[11]㊀雷鸣,刘书焕,宗鹏飞,等.SOI 硅微剂量探测器对中子和伽马辐射场线能谱测量的GEANT4模拟研究[J].辐射防护,2017,37(3):169-173.LEI Ming,LIU Shuhuan,ZONG Pengfei,et al.GEANT4simulation of silicon-on-insulator microdosimeter for monitoringlineal spectra of neutron and gamma mixed field[J].Radiation Protection,2017,37(3):169-173.Simulation of charge collection and energy deposition characteristicsin physical structure design of SOI-Si microdosimeterYAN Xuewen 1,2,JIN Haijing 1,2,LI Hua 1,2,LI Deyuan 1,2,QIAO Pei 1,2,NIU Mengqing 1,2(1.China Institute for Radiation Protection,Taiyuan 030006;2.Shanxi Provincial Key Laboratory for TranslationalNuclear Medicine and Precision Protection,Taiyuan 030006)Abstract :The charge collection characteristics and energy deposition characteristics of SOI-Si microdosimeterwere studied by using TCAD and Monte Carlo method.The variation of electric field distribution with the shapeand size of detection unit,electrode injection depth,incident particle type and energy was analyzed.And thevariation of the micro dose spectrum with the shape and size of the detection unit and the thickness of the PMMAconversion layer was also analyzed.The simulation results showed that in the range of 10μm,the cylindrical or cubic structure of the silicon detection unit had little influence on the charge collection efficiency and energy deposition.The higher the detection unit height and the smaller the radius,the higher the charge collectionefficiency.The thickness of PMMA conversion layer had a certain influence on the microdose spectrum.Withthe increase of PMMA thickness,the proportion of secondary particles generated by neutron and γ-ray that were stopped in the silicon sensitive region will increase,which leads to the increase of the peak value of the microdose spectrum.Key words :SOI-Si microdosimeter;charge collection;energy deposition;microdose spectrum㊃054㊃。
SOI压力传感器高压失效分析
的内部应力低于预期值。使用有限元方法进行仿真，验证刻蚀槽的底部的楔形结构导致器件背腔根部侧二氧化硅的
切应力集中，导致二氧化硅层与器件硅层的脱落，进而造成器件耐压提前失效的猜想。当器件内部最大应力达到
410 MPa 附近时，将会导致器件破裂失效的发生。
关键词: SOI 压力传感器; 耐高压; 提前失效; 仿真验证
从实验结果可知器件的耐压能力未能超过 1 MPa。为了进一步提升器件的耐压能力，制作出 具有更高耐压强度的压力传感器，本文采用了两种 方式增加器件的耐压能力：1）增加器件硅层的厚度 至 50 µm； 2） 减 小 背 腔 尺 寸 至 1 400 µm×350 µm。 器件的正、反面如图 4 所示。图 4(a) 展示了器件的 正面形貌，包括 IDT 部分与用于连线的焊盘部分， 图 4(b)、(c)、(d) 展示了背腔的形状与大小。
第 47 卷 第 6 期
王 韬，等：SOI 压力传感器高压失效分析
151
1) 首先在洁净的 SOI wafer 上利用物理气相沉 积生长出 AlN(1 µm)/Mo(0.2 µm)。其中，AlN 作为 器件的压电薄膜，膜的质量将决定整个器件的性能 的有无与好坏，金属 Mo 将在后续制作插指电极与 布拉格反射栅。
器件的耐高压能力（过载压力）指器件发生损 坏失效前能承受的最大压力，所以器件的压力传感 量程是低于器件的过载能力的。通过对市面上压力 传感器调研可知，通常压力传感器的线性压力响应 范围是其耐高压能力的 2/3 甚至更低。而传感器的 量程在压力传感器的线性压力响应范围内，所以耐 压能力一般是量程的 1.5 倍或更高。为了研究如何 提高压力传感器的耐高压能力，进而提升器件的量 程，需对压力传感器耐压失效的机理进行分析。本 文面向基于 MEMS 技术的 SOI 压力传感器高压失 效问题，以 SAW（声表面波）器件为对象，通过实验 测量器件的耐压极限并对器件内部应力进行仿真， 对器件的耐高压失效特性进行了研究与分析。
使用微芯片集成电解质 - 绝缘体半导体传感器上的适体检测蛋白激酶
Sensors and Actuators B 248(2017)973–979Contents lists available at ScienceDirectSensors and Actuators B:Chemicalj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /s nbDetection of protein kinase using an aptamer on a microchip integrated electrolyte-insulator-semiconductor sensorRohit Chand a ,b ,Dawoon Han a ,Suresh Neethirajan b ,Yong-Sang Kim a ,∗a School of Electronic and Electrical Engineering,Sungkyunkwan University,Suwon,Gyeonggi,16419,South Korea bBioNano Laboratory,School of Engineering,University of Guelph,Guelph,Ontario,N1G 2W1,Canadaa r t i c l ei n f oArticle history:Received 15October 2016Received in revised form 22January 2017Accepted 22February 2017Available online 24February 2017Keywords:Aptamer Biosensor CapacitanceElectrolyte-insulator-semiconductor MicrochipProtein kinase Aa b s t r a c tHerein,we developed a microchip electrolyte-insulator-semiconductor (EIS)sensor for the capacitive detection of protein kinase A (PKA).EIS sensing is customarily performed in a Teflon cell to define the sensing area.However,in this work,a rapid prototyping technique was followed to integrate polymeric microchip,a reference electrode,and the EIS sensor.The aptameric peptide was used for one-step and label-free detection of PKA enzyme.The thiolated PKA-specific aptamer was immobilized on the gold nanoparticles decorated EIS sensor surface.The detection of PKA in microchip was based on the change in surface charge of EIS sensor.We also analyzed the ability of microchip-EIS sensor to distinguish between buffers at different pH.An average sensitivity of 96mV/pH for a pH range of 5–9was obtained.The quanti-tative detection of PKA was performed by analyzing the capacitance-voltage curve after the aptamer-PKA interaction.The EIS sensor showed a detection limit of 2U/mL with a relative linearity from 10U/mL to 80U/mL for the detection of PKA.This study proposes an integrated and point-of-care applicable biosensor for the rapid diagnosis.©2017Elsevier B.V.All rights reserved.1.IntroductionProtein kinases are enzymes that mediate the transfer of a phos-phate group from adenosine triphosphate to a target protein,thus monitoring the cellular life.Regulation of protein function through phosphorylation is an important part of the post-translational mod-ification.Altering the phosphorylation of intracellular proteins is a common mode of action of many toxins and pathogens.Several medical conditions,including cancers,Alzheimer’s,and autoim-mune diseases are linked to irregular phosphorylation of protein [1,2].The extracellular protein kinase A level rises up to 20U/mL,whereas the total kinase concentration is much higher in the cancer patients [3].Therefore,determination of protein kinase is crucial in terms of biochemical diagnosis.Conventional techniques like radioisotope labeling,mass spec-troscopy,or enzyme-linked immunosorbent assays based kinase detection consume many expensive and hazardous reagents and typically require long durations for analysis [4,5].Additionally,miniaturization of these techniques for the point-of-care use is quite not possible.Electrochemical and optical based detec-tion are modern techniques and has proved to be an efficient∗Corresponding author.E-mail addresses:yskim651@ ,yongsang@ (Y.-S.Kim).approach [6,7].However,most of these modern approaches depend on the kinase-catalyzed phosphorylation of peptide and require extensive labeling steps.Therefore,detection of a kinase enzyme through phosphorylation of peptide,involving multiple washing,incubation,reaction,and detection sequence is time-consuming,expensive,and laborious.Besides,use of multiple biomolecules for recognizing and reporting reduces the shelf life of biosensors.To overcome these limitations,in our previous work,we designed one-step capacitive aptasensor on metal-insulator-semiconductor (MIS)and electrolyte-insulator-semiconductor (EIS)platforms [8].On comparison of the two sensing platforms,we concluded that the EIS based sensors are highly sensitive for biosensing.EIS sensors are simple ion-sensitive field-effect tran-sistors (FET)with capacitive detection [9].EIS sensing is based on the change in gate voltage ensuing due to the release of protons (change in local pH)or intrinsic charge of the biomolecules dur-ing bio-molecular interactions [10,11].Focusing on the isoelectric point (pI)of the biomolecule can increase or reverse the polarity of biomolecules.The change in the local surface charge modulates the space-charge of the semiconductor-insulator interface leading to a shift in the gate voltage [10].In the last few years,a number of EIS sensors for detecting bio-molecular interactions were reported which rely on the release of protons or change in the surface charge.Schoning et al.have exten-sively studied and reviewed the application of EIS sensors [9].EIS/10.1016/j.snb.2017.02.1400925-4005/©2017Elsevier B.V.All rights reserved.974R.Chand et al./Sensors and Actuators B248(2017)973–979sensors have been employed to detect rheumatoid arthritis,urea, glucose,DNA amplification,and KRAS gene[12–16].Recently,an EIS sensor for protein kinase C,ion-sensitivefield effect transistor for creatine kinase II,and carbon nanotubefield effect transistor for protein kinase A were reported[17–19].Their detection depends on the time consuming kinase-catalyzed phosphorylation of peptide. In addition,these FET based sensors have a small detection range. Another drawback of these EIS sensors is the lack of an integrated microchip-based sensing platform.In the majority of EIS sensors, the sensing area is defined by a Teflon cell or patterned SU-8struc-ture.For the analysis,an Ag/AgCl reference electrode is inserted into buffer reservoir on the sensor surface or the total sensor is dipped in the electrolyte-containing beaker[13,15].This makes the sen-sor unfit for disposable and point-of-care use.To the extent of our knowledge,only one group has developed an EIS sensor integrated with the microfluidic device for capacitive biosensing[14,20].In this study,we developed a polymeric microchip-EIS sensor for the label-free and one-step detection of protein kinase A(PKA) using PKA-specific aptameric peptide.The EIS sensor was com-prised of silicon dioxide(SiO2)grown on the p-type silicon(Si)as the substrate.The surface of the EIS sensor was functionalized with aptamer to make it selective for the PKA and to prevent nonspe-cific interaction.Aptamers have attracted a considerable attention because of several advantages over antibodies[21].Aptamers are thermally stable,easy to design and manufacture,and have unlim-ited applications.The fabrication of polymeric microchip follows a low cost and effortless procedure for integrating the EIS sen-sor.A rapid prototyping technique for a microfluidic system using polymerfilm and double-sided tape,in place of commonly used glass and polydimethylsiloxane,was developed to detect the PKA. The detection was based on the change in local surface charge due to aptamer-PKA interaction.Scanning electron microscopy, atomic force microscopy,Fourier transform-infrared spectroscopy, and capacitive analysis was used to study the surface modification and validation of the EIS sensor.Capacitance-voltage curves were recorded to detect the presence of PKA.As a proof of concept,we detected PKA in the spiked human cell sample.The microchip-EIS sensor benefits in a reduced reagent consumption,integrated and point-of-care analysis,and has the possibility of multiplexing with other biosensors.2.Materials and methods2.1.MaterialsHydrogen tetrachloroaurate(III)hydrate(HAuCl4·3H2O), sodium citrate,3-Mercaptopropyl)trimethoxysilane(MPTS), tris(hydroxymethyl)aminomethane(Tris),sodium chloride,and hydrochloric acid of analytical grade were purchased from Sigma-Aldrich(St.Louis,MO,USA).Polyethersulfone(PES)films were obtained from Fine chemicals(Korea).cAMP–dependent protein kinase A and protein kinase buffer was purchased from New England Biolabs(Ipswich,MA,USA)and stored at−20◦C.Thiolated aptameric peptide(Mpr-TTYADFIASGRTGRRNAIHD)was obtained from AnyGen co.Ltd(Korea).Fourier transform-infrared(FT-IR) spectra of the samples were collected between wavenumbers400 and4000cm−1at room temperature,using a Agilent Technologies Cary630FT-IR spectrophotometer coupled with an attenuated total reflectance(ATR)device.Atomic force microscopic analysis of sensor surface was performed using XE-100(Park systems, Korea).All other reagents were of analytical grade and purchased from Sigma-Aldrich.Ultrapure de-ionized(DI)water was used throughout the experiment.2.2.Synthesis of gold nanoparticlesThe AuNPs(d≈16nm)were synthesized using a seedless method as described before[22].Briefly,20mL of1.0mM aque-ous HAuCl4·3H2O solution wasfirst brought to a boil.Next,2mL of 38.8mM aqueous solution of sodium citrate was added,which was then boiled for10min until the color changed to deep red.The syn-thesized particles were characterized using UV–vis spectroscopy and scanning electrode microscope.2.3.Fabrication of EIS sensorsp-doped silicon substrate with a resistivity of10W-cm was used for the fabrication of sensors.The Si wafer was cleaned using a standard Radio Corporation of America(RCA)process.A50nm thick SiO2was grown on the Si substrate through plasma-enhanced chemical vapor deposition.Next,the back of Si wafer was primed using the wafer back grinding process to obtain a200m thick substrate.After priming,100nm thick aluminum(Al)was ther-mally deposited on the back of Si wafer using a vacuum thermal evaporator to serve as a back contact.2.4.Surface functionalization of the EIS sensorsThe SiO2surface of EIS sensor wasfirst treated the with O2 plasma for5min at50sccmflow rate and5×10−2Torr pressure. The O2plasma treatment activated the hydroxyl groups on the SiO2 surface,which then reacts with the silane molecule.Silanization of the SiO2surface was performed by dipping the EIS sensor in1% MPTS-toluene solution for3h.The reaction between the hydroxyl group of the EIS surface and the silane group of the MPTS formed a self-aligned monolayer,leaving free thiol group on the top.The silanized surface was thoroughly rinsed with the toluene followed by the ethanol.The EIS sensor was heated at110◦C for15min to strengthen the silane bonds and activate thiol groups.Next,the syn-thesized AuNPs were allowed to anchor on the MPTS modified EIS sensor for6h.The reaction between thiol groups of the MPTS and Au captured the AuNPs on the EIS sensor.The AuNPs modified EIS sensor was characterized by the scanning electron microscopy and capacitance–voltage(C–V)analysis.The functionalization of the EIS sensor wasfinalized after immobilizing the aptamer solution on the AuNPs for6h at4◦C.2.5.Fabrication of EIS microchipThe rapid prototyping technique for microchip based on a poly-merfilm and the double-sided tape was employed(Fig.1(a)).The fabrication technique was adopted from the previously reported works[1,23].For this purpose,we used polyethersulfone(PES)films and3M TM double-sided tape.The chip was fabricated in three parts, where,thefirst bottom PESfilm layer contained the100nm thick Al electrode for the back contact with the EIS sensor.The aptamer functionalized EIS was bonded on the Al electrode using a thin layer of conductive silver gel.The middle double-sided tape contained thefluid network.The tape formed a reservoir with an active area of5mm×5mm.The top PESfilm layer contained the inlet and outlet holes for the sample.For laying the reference electrode,a shadow mask containing the electrode pattern was attached to the top PESfilm.Then,in a thermal vacuum evaporator,titanium layer was deposited on the PESfilm as an adhesion layer,followed by a layer of silver.The silver electrode was treated with50mM fer-ric chloride for50s followed by rinsing with DI water,to obtain a thin AgCl over the deposited Ag electrode.The three parts were aligned under a simple optical microscope and kept under pres-sure for30min.The above technique enabled a rapid prototyping of microchip without the use of a clean room facility and sophisti-R.Chand et al./Sensors and Actuators B248(2017)973–979975Fig.1.(a)Schematic of the polymeric microchip,E1=electrode for back contact,(b)Structure of the EIS sensor,and(c)Scheme of aptamer-based PKA detection on the microchip-EIS sensor.cated instruments.The aptamer terminated EIS sensor integrated into polymeric microchip was further used for the detection of PKA.2.6.pH sensing using microchip-EIS sensorsTo verify the pH sensing ability of gold nanoparticle terminated EIS sensors,2mM Tris-HCl buffers with pH ranging from5to9 were used.The Tris-HCl buffer was injected using a syringe into thefluid channel of the microchip and electrical response of the EIS sensor was measured for each pH.The C–V analysis on microchip-EIS was performed using a Hewlett-Packard(HP)4284A LCR meter. The thinfilm Ag/AgCl electrode was used as the reference electrode. The gate voltage(V G)was swept at a frequency of1000Hz with a superimposed AC signal of10mV.2.7.Protein kinase A detection on microchip-EIS sensorsThe one-step detection of PKA was performed by adding10L of different concentrations of PKA in1X PKA buffer on the aptamer functionalized EIS sensors.The PKA was allowed to interact with the aptamer at25◦C.After the interaction,the reservoir wasfilled with2mM Tris-HCl buffer(pH7)for the C-V analysis.2.8.Detection of PKA in cell sampleHuman prostate cancer cell line DU145was obtained from American Type Culture Collection(USA).Cells were maintained in RPMI-1640medium supplemented with10%fetal bovine serum at 37◦C in a humidified5%CO2incubator.Cells from subcultures were supplemented with0.01%trypsin-EDTA(Sigma-Aldrich,USA)and mixed with1X PKA buffer containing different concentrations of PKA.3.Results and discussion3.1.Characterization of microchip-EIS sensorThe structure of the fabricated microchip-EIS sensor is shown in Fig.1(a).The bottom and top PESfilm contained electrode for the back contact and Ag/AgCl thin-film reference electrode,respec-tively.The tape providedfluidic connection and reservoir for the analyte and buffer during analysis.The structure of the EIS sensor is elaborated in Fig.1(b).The EIS sensor consists of a SiO2layer as an active material and silicon as a semiconducting layer.A mono-layer of citrate-capped AuNPs was generated on the SiO2film using MPTS as the linker molecule.The monolayer serves as a supporting layer for the thiolated PKA aptamer and additional gating layer.The presented fabrication methodology makes it easy to independently functionalize the EIS sensor in bulk and quickly integrate with the polymeric microchip.Each modification step of the EIS sensor sur-face was characterized by means of contact-angle measurements with a12L drop of DI water.Fig.3(a)presents the results of the water contact-angle measurements of a bare SiO2surface,O2 plasma treated SiO2surface,and MPTS functionalized surface.The hydrophilicity of the surface increased significantly to a contact angle of∼7.8◦after the plasma treatment from a contact angle of ∼42◦for a bare SiO2.The increased surface hydrophilicity was due to the increase in hydroxyl groups.The sensor surface modified with MPTS regained the hydrophobicity(contact angle=∼37◦).The change in the surface property of SiO2confirms the silanization of sensor.Fig.S1shows the scanning electron microscopic analysis of EIS sensor surface to confirm the attachment of AuNPs.As evi-dent from the image,highly resolved AuNPs with an average size of16±2nm were attached on the SiO2surface.Fig.S2shows the C-V response of EIS sensor after immobilizing negatively charged citrate-capped AuNPs.The immobilization of AuNPs altered the V G of EIS sensor.The local charge on the surface of gate insula-tor affects the depletion region,thereby shifting the C-V curve of the EIS sensor.A positive shift in the V G was seen due to the attach-ment of negatively charged AuNPs to the SiO2surface.The scheme for PKA analysis using EIS sensor is summarized in Fig.1(c).First,the976R.Chand et al./Sensors and Actuators B 248(2017)973–979thiolated aptamers were immobilized on the AuNPs through thiol-gold chemistry.Next,different concentrations of PKA solution in 1X reaction buffer was added to the sensor surface for interaction with the aptamer.3.2.pH sensing using microchip-EIS sensorsThe detection of PKA on microchip-EIS sensor was based on the change in the surface charge and local surface pH.Therefore,at first,we analyzed the ability of microchip-EIS sensor to distinguish between buffers at different pH.For the analysis,we fabricated EIS sensor with AuNPs terminated surface.The buffers from pH range 5–9were injected through the microchannel and the corresponding C-V response was measured.The ionic groups present in the buffer adsorbs on the SiO 2surface,thus changing the surface charge.This leads to a shift in the C-V curve of the EIS sensor.A response char-acteristic of EIS sensor at different pH buffers is shown in Fig.2.The gate voltage (V G )shifted towards negative and positive when the sensor surface was exposed to acidic and basic buffer,respec-tively.A good relationship was seen between the pH and shift in the V G with an average sensitivity of 0.96V/pH (R 2=0.99).This confirms the sensitivity of the microchip-EIS sensor towards the surface charge,which is useful for the PKA detection.3.3.Optimization of experimental parameterThe concentration of aptamer is an important parameter for the detection of PKA.The aptamer used in this work was a 20aminoFig.2.The response of microchip-EIS sensor at different pH buffers w.r.t thin-film Ag/AgCl electrode:(a)C-V curves of EIS sensor at pH 5–9,(b)Relationship between pH and gate voltage.Buffer:2mM Tris–HCl.acid long peptide that selectively binds with the PKA [24,25].The isoelectric point of the aptamer is around pH 9.5,therefore it is positively charged at the neutral pH value [26].To determine the optimal concentration of aptamer that covers the surface of AuNPs monolayer,the surface was incubated with different concentration (0–200M)of the aptamer for 6h.After formation of the aptamer layer,the surface was rinsed with the DI water.The shift in the C-V curve was monitored to establish the extent of deposition.As shown in Fig.S3,the immobilization of positively charged aptamer neutralized the negative charge of the AuNPs to a certain level,thus shifting the V G towards the negative direction.The shift in the C-V curve of the microchip-EIS sensor saturated when the con-centration of aptamer increased beyond 100M.Thus,100M of aptamer was selected as the optimal for depositing on the AuNPs for further experiments.The interaction time of the PKA and aptamer determines the per-formance of the EIS sensor.The optimization of reaction time was studied in the range of 0–30min in the presence of PKA.As shown in Fig.S4,the C-V curve shifted towards the negative with the increas-ing reaction time,reaching a saturation at 20min.The saturation of signal symbolizes the complete binding of the aptamer and PKA.Therefore,a reaction time of 20min was used in the further work.3.4.Detection of protein kinase A on microchip-EIS sensorsThe aptamer acts as a pseudo-substrate for the PKA enzyme,because of sequence complementarity with the binding site of the PKA.It has been extensively reported that the interaction of aptamer with the target changes the structure,total charge,and charge distribution of the aptamer [27,28].Therefore,the EIS sen-sor functionalized with the kinase-specific aptamer was used for the selective,sensitive,and label-free detection of the enzyme.The AuNPs terminated EIS sensor was functionalized with 100m of PKA-specific aptamer and was allowed to interact with PKA for 20min at 25◦C.The sensor surface was rinsed with DI water to eliminate the unbound PKA.The interaction of aptamer with PKA was confirmed by FT-IR spectra as shown in Fig.3(b).The appear-ance of characteristic peaks of the aptameric peptide (Fig.3(b)curve A),located at 1673cm −1(HNC O),1505cm −1(aromatic ring)and 1468cm −1(C N)established the immobilization of aptamer on the gold surface.An increase in the peak intensity and presence of func-tional groups commonly found in the PKA enzyme confirmed the interaction and binding of aptamer with PKA (Fig.3(b)curve B).We also performed the surface analysis of EIS sensor before and after interaction of aptamer and PKA to verify the biosensing (Fig.S5).Non-contact mode AFM topographs of the aptamer immobi-lized gold surface (Fig.S5(a))and after aptamer PKA interaction (Fig.S5(b))shows an increase in the surface roughness.In Fig.S5(b),several distinctive rough spots on the surface were apparent for the presence of aptamer-PKA complex [29,30].For the microchip-EIS sensing of PKA,different concentrations of PKA in 1X reaction buffer was injected in the microchip and incu-bated with the aptamer.The pI of the PKA is pH 8.84;therefore,its interaction with aptamer further increases the positive charge on the sensor surface.This change in the charge and density on the sen-sor surface was recorded using C-V analysis for label-free detection of PKA.After the aptamer-PKA interaction,the reservoir was slowly filled with the tris buffer saline (TBS,2mM tris,20mM NaCl,pH 7)and then the C-V curves were analyzed.The strength of the buffer was kept low and the pH was set to 7to reduce the effects of ions on the electrical response of the sensor.Fig.4(a)shows the C-V curves for label-free capacitive detection of PKA on microchip-EIS sensor.PKA solutions with a concentra-tion range of 1–80U/mL were detected using the proposed sensor.As can be seen from Fig.4(a),with the increasing concentration of PKA,the V G gradually shifted more towards the negative dueR.Chand et al./Sensors and Actuators B248(2017)973–979977Fig.3.Characterization of microchip-EIS sensor:(a)Water contact-angle analysis of pristine(A),O2plasma treated(B),and MPTS immobilized(C)SiO2surface;(b)FT-IR spectra of immobilized aptamer(A)and aptamer-PKA complex(B);(c)C-V curve for the detection of PKA without aptamer,Buffer:2mM Tris–HCl,pH7,using thin-film Ag/AgCl electrode.to the change in surface charge of EIS sensor.The microchip-EIS sensor with immobilized aptamer produced a V G of−0.451V.Due to the interaction of aptamer with60U/mL of PKA,the V G shifted to−0.775V.Fig.4(b)shows the response of microchip-EIS sensor with respect to the different concentration of PKA.The error bar represents the standard deviation of three independent analysis.A proportional shift in the V G was seen with the increasing concentra-tion of PKA.The microchip-EIS sensor showed a limit-of-detection of2U/mL(S/N=3)and a relative linear range from10to80U/mL.To prove that the obtained shift in the V G of microchip-EIS sen-sor is the result of aptamer-PKA interaction only,we analyzed the PKA on AuNPs terminated sensor surface(without aptamer).The attempted detection of PKA without aptamer produced a negligi-ble shift in the C-V curve(Fig.3(c)).The minor shift in the C-V curve is presumably due to the electrostatic interaction of nega-tively charged AuNPs and positively charged PKA.However,a large shift in the V G was observed upon interaction of aptamer and PKA (Fig.4)which is because of the higher binding affinity of aptamer to the PKA.The lifetime of microchip-EIS sensor was investigated to study the stability of the PKA sensor.Several aptamer modi-fied microchip-EIS sensors were stored at4◦C for20days and the variation in signal was analyzed.The results demonstrated that the prepared PKA sensor has good stability and almost remained unchanged for up to15days(Fig.5(a)).A∼10%decrease in the performance of microchip-EIS sensor was seen after20days.The specificity of the proposed aptamer functionalized microchip-EIS sensor was examined by replacing the PKA with other biological molecules.As shown in Fig.5(b),the analysis of non-specific tar-gets produced no noticeable change in the signal.The PKA-specific aptamer did not interact with other biomolecules,proving the specificity of the aptamer.Based on these results,we propose a microchip-EIS sensor for integrated,label-free and one-step sens-ing of protein kinase A.3.5.Capacitive detection of protein kinase A in cell sampleThe potentiality of the proposed microchip-EIS sensor was demonstrated by detecting PKA in the presence of human cell line.978R.Chand et al./Sensors and Actuators B 248(2017)973–979Fig.4.The response of microchip-EIS sensor for the detection of PKA w.r.t thin-film Ag/AgCl electrode:(a)C-V curves of EIS sensor for PKA from 0to 80U/mL,(b)Relationship between PKA concentration and gate voltage.Buffer:2mM Tris–HCl,pH7.DU145cells in conditioned medium were spiked with the reaction mixture containing different concentrations of PKA,to simulate a biological sample.For the PKA-aptamer interaction,10L of spiked cell sample was injected and incubated with the aptamer-modified microchip-EIS sensor as discussed earlier.The interaction of aptamer and PKA present in the sample was then analyzed using C-V curves.Fig.6summarizes the analyses,demonstratingFig.6.Detection of PKA in the spiked human cell sample.good recoveries with respect to the concentrations of spiked PKA.The device showed high signal to noise ratio with EIS sensor pre-cisely distinguishing between the spiked PKA and other interfering molecules present in the medium.Therefore,the microchip-EIS sensor can be used to detect PKA in cell samples or serum from patients.4.ConclusionIn conclusion,this work describes a strategy for development and integration of a polymeric microchip with EIS sensor for detec-tion of PKA.The proposed sensor was highly sensitive towards the change in pH.Aptamer immobilized sensor surface facilitated in rapid biosensing.Interaction of aptamer and PKA on microchip-EIS sensor produced a shift in the gate voltage.The sensor showed a detection limit of 2U/mL for PKA.The developed method offers attractive features like one-step detection,integrated analysis,and costless polymeric microchip.The biosensor exhibited a high response,low detection limit,and specificity towards the PKA.A polymer-based microchip makes this work beneficial for dis-posable and point-of-care use.The proposed sensor can also be integrated with other biosensors for multiplexedanalysis.Fig.5.The stability (a)and specificity (b)of microchip-EIS sensor,BSA =Bovine serum albumin.R.Chand et al./Sensors and Actuators B248(2017)973–979979Appendix A.Supplementary dataSupplementary data associated with this article can be found,in the online version,at /10.1016/j.snb.2017.02.140. 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55–75.[23]P.K.Yuen,V.N.Goral,Lab Chip10(2010)384–387.[24]H.Eldar-Finkelman,M.Eisenstein,Peptides targeting protein kinases:strategies and implications,Curr.Pharm.Des.15(2009)2463–2470.[25]D.B.Glass,H.C.Cheng,B.E.Kemp,D.A.Walsh,Differential and commonrecognition of the catalytic sites of the cGMP-dependent andcAMP-dependent protein kinases by inhibitory peptides derived from theheat-stable inhibitor protein,J.Biol.Chem.261(1986)12166–12171.[26]L.P.Kozlowski,IPC−Isoelectric Point Calculator,2016.Available:http://dx./10.1101/049841.[27]M.Zayats,Y.Huang,R.Gill,C.-a.Ma,I.Willner,Label-free and reagentlessaptamer-based sensors for small molecules,J.Am.Chem.Soc.128(2006)13666–13667.[28]M.C.Rodriguez,A.-N.Kawde,J.Wang,Aptamer biosensor for label-freeimpedance spectroscopy detection of proteins based on recognition-induced switching of the surface charge,mun.(2005)4267–4269.[29]Y.H.Tan,J.R.Schallom,N.V.Ganesh,K.Fujikawa,A.V.Demchenko,K.J.Stine,Characterization of protein immobilization on nanoporous gold using atomic force microscopy and scanning electron microscopy,Nanoscale3(2011)3395–3407.[30]J.A.U.Paredes,A.Polini,W.Chrzanowski,Protein-based biointerfaces tocontrol stem cell differentiation,in:D.Hutmacher,W.Chrzanowski(Eds.),Biointerfaces:Where Material Meets Biology,RSC publications,2014,2017, pp.1–29.BiographiesRohit Chand:Rohit obtained his Ph.D.in Electronic and Electrical Engineering from Sungkyunkwan University,South Korea and M.Sc.from KIIT University,India.He has developed electrochemical and microfluidic biosensors for the detection of can-cer biomarkers.Rohit worked as a post-doctoral fellow and research professor at Sungkyunkwan University,South Korea.At present,he is working as a post-doctoral fellow at BioNano Lab,University of Guelph,Canada.His research work involves micro-fabrication,surface functionalization,biosensors,and lab-on-a-chip devel-opment.Dawoon Han:Dawoon is currently a doctoral candidate in the NEMS Lab at Sungkyunkwan University,South Korea.She completed her MS degree in Nano Sci-ence and Engineering from Myongji University,South Korea.Her research interests are in the development of electrochemical,field-effect transistor,and lab-on-a-chip based biosensors.Suresh Neethirajan:Prof.Neethirajan is an assistant professor in Biological and Biomedical Engineering program of the University of Guelph with demonstrated research excellence and experience in large-scale multi-faceted international col-laborative research projects.He is currently directing the state-of-the-art BioNano Lab and the team leader of the Precision Livestock Biosensor group at Guelph. Yong-Sang Kim:Prof.Kim is a professor at the School of Electronic and Electri-cal Engineering and head of the Nano-Electronics and Microfluidic Sensors lab of the Sungkyunkwan University,South Korea.Prior to this,he was a professor in the Dept.of Electrical Engineering and director of Nano-Bio Research Centre at Myongji University,South Korea.He also served as an associate researcher at Univ.of Cal-ifornia at Berkeley,U.S.A.Prof.Kim’s research focuses on developing organic and oxide based TFTs for biological detection and use in electrical circuits.He also works on the development of microfluidic platforms for the electrochemical analysis of biomolecules and organic solar cells.He has published over150papers in several peer-reviewed journals.。
MEMS所使用的功能材料
MEMS讲义（2）：MEMS所使用的功能材料功能材料是指那些具有优良的电学、磁学、光学、热学、声学、力学、化学、生物医学功能，特殊的物理、化学、生物学效应，能完成功能相互转化，主要用来制造各种功能元器件而被广泛应用于各类高科技领域的高新技术材料。
MEMS所使用的功能材料大大拓宽了MEMS 研究领域，提高和改善了MEMS器件和系统的性能，对实现特殊器件或者功能性器件做出了重大贡献。
一：SOI材料SOI （Silicon-on—Insulator）是一类较新的材料和结构, SOI 结构综合了体硅和SOI 材料各自的优点，具有部分绝缘和部分导电的特性. 一般采用键合方式来形成SOI结构.SOI 材料，即绝缘体上的硅材料，被国际上公认为“二十一世纪硅集成电路技术”的基础。
SOI材料有SOS ，FIPOS ，ZMR , SI2MOX 等。
目前SOI 材料主要用于低压、低功耗超大规模集成电路和抗辐照、耐高温的特种集成电路。
SOI 的另一个重要应用领域是制备微电子机械器件,相比传统的体硅压力传感器，用SOI 材料制备压阻式SOI 传感器具有耐高温的特点.采用SOI材料可以制备也比较理想的器件，但并不是说这种器件就是完美的，还存在着若干问题有待解决，如自加热效应、翘曲效应、寄生双极晶体管效应及浮体效应等。
二:压电材料（PZT）压电材料在外界振动激励作用生形变，引起材料内部应力的变化，其内部电荷发生位移从而产生了电场.因当压电晶体受到应力作用时，在它某些面上产生电荷，且应力与面电荷密度之间存在线形关系，这个现象称为正压电效应。
而当压电晶体受到电场作用时，在它的某方向上产生应变，且电场强度与应变之间存在线形关系，称为逆压电效应。
在压电效应中，机械域和电域的能量可以相互转换。
压电材料受到的机械应力产生电场，机械能转化为电能，这种转换模式称为传感器模式；在压电材料上外加电压，引起机械形变，电能转化为机械能，这中转换模式称为执行器模式。
SOI／SIMOX材料导电类型反型的研究
SOI／SIMOX材料导电类型反型的研究
温梦全;周彬
【期刊名称】《微电子学》
【年(卷),期】1996(26)3
【摘要】采用大剂量氧离子注入（１７０ｋｅＶ，１．８×１０１８＋／ｃｍ２）ｐ型单晶硅，高温退火（１３００℃，６ｈ）后形成ＳＯＩ－ＳＩＭＯＸ（ＳｉｌｉｃｏｎＯｎＩｎｓｕｌａｔｏｒ－ＳｅｐａｒａｔｉｏｎｂｙＩｍｐｌａｎｔａｔｌｏｎｏｆＯｘｙｇｅｎ）样品。
俄歇电子能谱仪和扩展电阻仪测试表明，该样品表层硅膜的导电类型由ｐ型反型为ｎ型。
ＳＩＭＯＸ样品的反型是硅中的氧施主所致，由近自由电子的类氦模型计算，ＳＩＭＯＸ样品中氧施主的电离能为０．１５ｅＶ，与早期文献报导的实验值一致。
【总页数】3页(P153-155)
【关键词】半导体材料;SOI;SIMOX;单晶硅;氧注入
【作者】温梦全;周彬
【作者单位】北京航空航天大学应用数理系
【正文语种】中文
【中图分类】TN304.01
【相关文献】
1.SIMOX样品导电类型反型的研究 [J], 温梦全;周彬
2.填充复合型导电高分子材料导电机理及导电性能影响因素研究概况 [J], 叶明泉;
贺丽丽;韩爱军
3.填充型导电复合材料载荷作用下导电逾渗研究 [J], 邵宇;蔡红雷;闫晓鑫;张弛;陈建康;张明华
4.复合型导电高分子材料导电性能影响因素研究概况 [J], 周祚万;卢昌颖
5.压电材料界面刚性导电型线夹杂的反平面问题 [J], 李显方;范天佑
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屏蔽槽SOI高压器件新结构和耐压机理
第26卷 第11期2005年11月半 导 体 学 报CHIN ESE J OURNAL OF SEMICONDUCTORSVol.26 No.11Nov.,20053国家自然科学基金资助项目(批准号:60436030) 2005204208收到,2005206203定稿Ζ2005中国电子学会屏蔽槽SOI 高压器件新结构和耐压机理3罗小蓉 李肇基 张 波 郭宇锋 唐新伟(电子科技大学IC 设计中心,成都 610054)摘要:提出具有屏蔽槽的SOI 高压器件新结构和自适应界面电荷耐压模型.该结构在屏蔽槽内产生跟随漏极电压变化的界面电荷,此电荷使埋层介质的纵向电场增加,同时使顶层硅的纵向电场降低,并对表面电场进行调制,因此屏蔽了高电场对顶层硅的影响.借助二维器件仿真研究器件耐压和电场分布与结构参数的关系.结果表明,该结构使埋氧层的电场从传统的3E Si 升高到近600V/μm ,突破了传统SOI 器件埋氧层的耐压值,大大提高了SOI 器件的击穿电压.关键词:屏蔽槽;自适应界面电荷;调制;纵向电场;击穿电压EEACC :2560B ;2560P中图分类号:TN386 文献标识码:A 文章编号:025324177(2005)11221542051 引言SOI 器件的高速、低功耗、高集成度等优越性能使其在VL SI 领域得到广泛关注[1],但其较低的纵向耐压限制了其在高压功率集成电路中的应用.为此,国内外众多学者提出了一些新结构[2～11].在Si/SiO 2界面引入电荷,利用SiO 2高临界击穿电场的特点,通过提高埋氧层电场而提高器件纵向耐压,是一种非常有效的方法.如在Si/SiO 2的界面插入N +薄层[2],但其漏电流较大,且需精确控制N +层的密度,否则将在表面源端或漏端提前击穿;注入阶梯埋氧层固定界面电荷(step fixed interface charge ,SF 2IC )在一定程度上缓解了上述两个问题[3],但其工艺相对略微复杂.本文提出屏蔽槽(shielding t rench ,ST )SOI 高压器件新结构,屏蔽槽束缚Si/SiO 2界面反型层的电荷,且该电荷是从源到漏逐渐递增的、跟随漏极电压而变化的自适应界面电荷,自适应电荷对纵向电场调制的同时还能改善横向电场分布,故可大大提高器件耐压.仿真结果表明,采用ST 结构,对Si 层厚度为4μm ,埋氧层厚度为1μm 的SO I LDMOS ,耐压可达635V ,而耐压超过600V 的传统SOI LD 2MOS ,需要4μm 以上的埋氧层和约20μm 厚的Si 层.可见,该结构不仅能够提高耐压,同时可以缩小SO I 器件的纵向尺寸,最大限度地克服自热效应和浮体效应,因此,本文所提出的结构对SOI 功率电子器件具有重要意义.2 器件结构和机理具有屏蔽槽结构的SO I LDMOS 器件结构如图1(a )所示.图中t s ,t ox 分别代表Si 层和埋氧层厚度.当漏极加较大正电压V d ,栅、源极和衬底接地时,Si/SiO 2界面Si 侧形成反型层.如果槽高H 足够大,就能阻止漂移区横向电场对反型层电荷的抽取,从而在槽底部束缚高浓度的空穴,如图1(b )所示.设槽内空穴的面密度为Q s ,则在Si/SiO 2界面,电位移连续性为:εox E ox =E Si εSi +Q s ,其中E Si ,E ox 和εSi ,εox 分别是界面处Si 和SiO 2的电场和介电常数.可见,随着Q s 的增加,E ox 将可从传统结构(Q s =0)的3E Si 提高至其临界击穿电场(本文选取600V/μm ).采用RESU RF 技术和结终端技术优化横向电场,可使器件击穿由纵向决定.在纵向电场最强的漏端下采用一维近似,SiO 2击穿前,器件的纵向电压可写成:V d =E Si t +Kt oxεSiQ s (1)第11期罗小蓉等: 屏蔽槽SOI高压器件新结构和耐压机理图1 具有屏蔽槽的SOI 器件原理图 (a )器件结构;(b )槽的结构及电荷分布Fig.1 Principle structure of SOI device with shielding trench (a )Device structure ;(b )Trench structure and charges distribution式中 K =εSi /εox ;t =015t s +Kt ox ,为SO I 器件的特征厚度.(1)式右边第一项是传统SO I LDMOS 的纵向压降.可见,高浓度的界面电荷能大大提高纵向耐压.Si/SiO 2界面纵向电场为E Si =V d -Kt ox Q sεs×1t (2)E ox =V d +t s Q s ,L d2εs×Kt(3) 可见,界面电荷产生如图1(b )所示的附加纵向电场E ′,E ″,该电场使埋氧层内纵向电场增强,同时削弱Si 层的电场,屏蔽高电场对Si 层的影响,因而提高了器件的纵向击穿电压.当然,如果槽内电荷密度过高,器件的击穿首先发生在埋Si/SiO 2界面SiO 2侧,则V d =E ox ,C tK-Q s2εSit s ,其中E ox ,C 为SiO 2的临界击穿电场.优化设计器件结构,当Si 和SiO 2中同时击穿时,器件击穿电压最高,此时V B =E Si ,C t s /2+E ox ,C t ox .与文献[2,3]在Si/SiO 2界面引入正电荷不同,本文中局域界面电荷密度为Q s (x )=2k 0T εSi p no /εrs ε0exp [q (V s (x )-<s (x ))/2k 0T ](4)式中 p n0是漂移区平衡空穴浓度;V s (x )为漂移区上表面电势;<s (x )为漂移区下表面电势,其从源到漏区逐渐增加.Q s 受V d ,<s ,t s ,t ox 以及槽形结构参数的调制.调节槽宽W 和槽间距D ,可使Si/SiO 2界面实现从源到漏区逐渐递增的准连续分布的界面电荷,该电荷对表面电场的调制作用使表面电场更均匀.槽内大部分区域电荷均匀分布,边角处电场集中使其电荷浓度稍高;同时,电场的横向分量使空穴在槽内靠近源极的一边浓度略高.平衡时,各屏蔽槽内横向电场为零,槽内等电势.考虑电荷分布的影响,引进形状因子k ,k 与槽的几何形状、t s 及t ox 有关,0<k ≤1,则有效电荷Q eff =kQ s .3 结果与讨论为了验证上述耐压机理的正确性,首先讨论漏端下纵向电场和电势分布.仿真结果表明,对传统结构的SO I LDMOS ,当t s =4μm ,t ox =1μm ,L =50μm ,最高击穿电压为191V 时,器件在Si/SiO 2界面Si 侧发生击穿.具有屏蔽槽的SO I LDMOS ,由于界面电荷对电场的调制作用,当W =D =H =1μm 时,击穿电压增至635V ,击穿发生在Si/SiO 2界面SiO 2侧.图2为传统结构和ST 结构在击穿电压下的纵向电场和电势分布.该图显示在Si/SiO 2界面,E Si 从传统结构的32V/μm 降低为ST 结构的12V/μm 1更重要的是,E ox 由97V/μm 增至其临界击穿电场600V/μm ,纵向击穿由Si 侧转移至SiO 2,此谓对Si 层高电场的屏蔽作用.ST 结构充分利用SiO 2高临界击穿电场的特点,使埋氧层承受器件纵向电压从传统结构的97V 提高为ST 结构的598V ,因而大大提高了器件的击穿电压.自适应界面电荷不仅能够调制纵向电场,而且能改善表面横向电场分布.图3(a )为传统结构、SF 2IC 以及ST 结构在其击穿电压下的表面电场分布,仿真中均采用t s =4μm ,t ox =1μm ,L =50μm ,N d =115×1015cm -3.可见,界面电荷相当于增加了漂移区浓度,使p +n 结处电场峰值增加,nn +结处电场峰值降低.值得注意的是,ST 结构与固定界面电荷线性分布的表面电场分布十分接近,这映证了界面电荷是从源到漏区逐渐递增、准连续的电荷,它使表面5512半 导 体 学 报第26卷图2 传统结构和ST 结构在击穿电压下的纵向电场和电势分布Fig.2 Vertical electric field and potential distribu 2tion under breakdown voltage for the conventional and STstructures图3 (a )击穿时表面电场分布;(b )ST 结构二维等势线分布Fig.3 (a )Surface electric field distribution under breakdown voltage ;(b )Equi 2potential contours of ST structure电场分布更加均匀.另一方面,在Si/SiO 2界面,由于平衡时各屏蔽槽内横向等电势,同时屏蔽槽均匀分布,因而界面电势从源到漏区呈阶梯状近似等差上升,这使得漂移区内等势线接近均匀分布(图3(b )),表面电势接近线性分布.可以预测,槽分布越密,等势线分布越均匀,表面电势越接近线性分布.根据RESU RF 原理,为了获得器件的最高横向击穿电压,漂移区的电荷总量———包括掺入杂质和界面电荷存在一个优值.图4展示了不同槽形结构参数的器件击穿电压与漂移区浓度的关系.随着高度H 的增加,槽对空穴的束缚作用加强,槽内局域空穴浓度更高,E ox 更大,所以耐压提高,相应地,其优化的漂移区浓度更小.同理可以解释W 和D 对耐压和漂移区浓度的影响:槽分布越密,界面电荷越接近连续分布,表面电势更接近线性分布,其耐压更高;同时,局域电荷总量越多,优化的漂移区浓度更小.W 和D 二者间,D 的影响更为明显.因为W 的增加可以通过增加漂移区浓度以适应漂移区的电荷总量最优,从而使器件保持高的耐压,只有当W 增加到一定值时,槽内电荷的对电场的调制作用大大削弱,耐压急剧下降,如果W 趋于无穷大,则变为普通SO I LDMOS 结构.当W 不变时,D 增加使束缚电荷的区域(W /(W +D ))减少,且槽的分布变疏,电荷分布的连续性变差,导致耐压下降.图5为器件结构参数对器件击穿电压的影响,仿真中采用t s =4μm ,t ox =1μm ,L =50μm ,N d =115×1015cm -3.可见,当t s ,t ox ,L ,N d 一定时,其最高击穿电压与某一固定的槽形结构对应.这是界面电荷对漂移区电荷总量调制的结果:屏蔽槽太密或者太高,漂移区电荷总量过高使源区表面或Si/SiO 2界面的SiO 2侧提前击穿,耐压降低;反之,则击穿首先发生在漏区表面或Si/SiO 2界面的Si 侧.相比之下,H 对耐压的影响最大,W 最弱,这可以通过前面的分析加以解释.图中也给出了击穿电压与漂移区长度的关系,当漂移区较短时,V B 随L 的增加而增加,说明此时击穿由横向决定;当L ≥50μm 时,器件发生纵向击穿,耐压达到饱和.图6为SO I 器件最高击穿电压与t s 的关系曲线.可见,SO I 器件在t s 较小和较大时击穿电压均较高,这是因为t s 较小时,Si 的临界击穿电场高且电离积分通道短,故击穿电压高;而t s 较大时,承受电压的耗尽层增加,器件耐压升高.具有屏蔽槽的SO I 器件,当t s >1μm ,其耐压远远高于传统SO I 器件,且当t s <10μm ,电势大部分压降落在SiO 2层上,所以击穿电压随t s 增加几乎不变,只有当t s 较6512第11期罗小蓉等: 屏蔽槽SOI高压器件新结构和耐压机理图4 击穿电压与漂移区浓度的关系Fig.4 Breakdown voltage versus driftconcentration图5 击穿电压与器件结构参数的关系Fig.5 Breakdown voltage versus the structure parame 2ters图6 击穿电压与Si 层厚度的关系Fig.6 Breakdown voltage versus the thickness of Si layer大时,Si 层承受电压增加使器件耐压逐渐上升.随着SOI 材料制备技术的发展,具有屏蔽槽的SO I 材料可以通过键合和图形氧注入两种方式实现.如果槽较深、埋氧层较厚,则采用键合方法:Si 片刻槽、高压氧化+淀积SiO 2、SiO 2表面平坦化、键合、减薄;如果槽较浅且埋氧层较薄,则采用SIMOX 技术:注氧(形成埋氧层)、图形氧注入(形成浅槽)、外延到所需Si 层厚度.4 结论本文提出具有屏蔽槽的SOI 高压器件新结构及界面电荷耐压机理.在外加电压作用下,屏蔽槽内产生跟随漏极电压变化的界面电荷,利用该电荷对电场的调制作用,通过增加埋氧层耐压和优化表面电场而达到提高器件击穿电压的目的.二维器件仿真结果表明,该结构使埋氧层内电场从传统SO I 的约3E Si 升高至其临界击穿电场,大大提高了器件耐压.该结构在保证较高耐压的同时可以减小纵向尺寸,因而最大限度地降低浮体效应和自热效应的影响,拓宽了SO I 器件在高压集成电路中的应用范围.参考文献[1] Udrea F ,Garner D ,Sheng K ,et al.SOI power devices.J Elec 2tron Commun Eng ,2000,12(1):27[2] Nakagawa A ,Yasuhara N ,Baba Y.Breakdown voltage en 2hancement for devices on t hin silicon layer/silicon dioxide film.IEEE Trans Electron Devices ,1991,38(7):1650[3] Guo Yufeng ,Li Zhaoji ,Luo Xiaorong ,et al.New structureand breakdown model of high voltage SOI devices wit h t he step buried 2oxide fixed charges.Chinese Journal of Semicon 27512半 导 体 学 报第26卷ductors,2004,25(12):1623(in 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voltage(>700V)in t hin SOI device.Proc3rd IntSymp on Power Semiconductor Devices and ICs,1991:31 [10] Akiyama H,Yasuda N,Moritani J,et al.A high breakdownvoltage IC wit h lateral power device based on SODI structure.Proceedings of International Symposium on Power Semicon2ductor Devices&ICs,2004:375[11] Tadikonda R,Hardikar S,Narayanan E M S.Realizing highbreakdown voltages(>600V)in partial SOI technology.Sol2 id2State Electron,2004,48:1655A Novel Structure and Its Breakdow n Mechanism of a SOIHigh Voltage Device with a Shielding T rench3L uo Xiaorong,Li Zhaoji,Zhang Bo,Guo Yufeng,and Tang Xinwei(I C Desi gn Center,Universit y of Elect ronic Science&Technolog y,Cheng du 610054,China)Absract:A novel SOI high voltage device structure with a shielding trench and its breakdown mode with a self2adapted interface charge are proposed.Interface charges that change with the drain voltage are introduced in the shielding trench.Interface char2 ges enhance the vertical electric field of the buried layer and reduce that of the top Si layer simultaneously.Furthermore,they al2 so modulate the surface electric field.So,interface charges shield the top Si layer f rom a high electric field.The breakdown volt2 age and electric field profile are researched for different device parameters for a ST structure by using a2D device simulator.It is shown that the electric field of buried oxide increases from about3E Si to600V/μm.It breaks through the limitation of the sustained voltage of the buried oxide layer of a normal SOI device and enhances the breakdown voltage of the SOI device re2 markably.K ey w ords:shielding trench;self2adapted interface charge;modulate;vertical electric field;breakdown voltageEEACC:2560B;2560PArticle ID:025324177(2005)11221542053Project supported by t he National Natural Science Foundation of China(No.60436030) Received8April2005,revised manuscript received3J une2005Ζ2005Chinese Institute of Electronics 8512。