Qtx+overview_09272010

Offline analytical
Keithley/KLA-Tencor
Q Vox Qmobile blanket 1988 Measure junction leakage +Q + dVsi/dt in-line light 1998 In-line gate dielectric Q Q until Vsi=0 performance (0.18 m) Cox = dQ/dV
Accumulation = an excess of „majority‟ charge carriers at the Si/SiO2 interface:
- - - - - - SiO2
Ec
+++++++ + + + + +
+ ++ ++++ + + + +
Ei Ef E + + + + v
Thin SiO2 or SiON on Si Si3N4 on rugged poly
Thin ONO stacks on Si
TEOS, PSG
Works on unpatterned „test‟ or „monitor‟ wafers
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KLA-Tencor Confidential
SiO2
Si
pbulk ni e
-
( Ei E f )
bulk
kT
-
-
Ec -
+ + + + + +
Ei Ef Ev + + + +
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KLA-Tencor Confidential
Si Band Energy
Si Depth
Review of MOS semiconductor physics
Electrical defects change device electrical operation and degrade yield
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KLA-Tencor Confidential
Quantox Description (cont’d)
Quantox requires a dielectric that can hold charge (i.e., acts as a capacitor when charge is applied) on a conducting or semiconducting substrate
Al Cu
Interface Trapped Charge, Qit
Oxide
e+
h+
D
Fixed Charge, Qf
e- h+
A
Silicon
FeB
Impurity/Defect Alkali contamination Fixed charge Interface charge Residual plasma surface charge Bulk, oxide trapped charge
History of corona measurements
Key seminal events: 1898: Lord Kelvin invented the Kelvin probe
Kelvin probe = Non-contact measurement of voltage Invented to measure workfunctions f of materials like brass and iron
If no current is flowing, Ef is a flat, straight line If Ef < Ei, then material is p-type
If Ef > Ei, then material is n-type
For p-type Si: At flatband condition, ideal (charge-free) oxide:
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KLA-Tencor Confidential
History of corona msmts. on semiconductors
Researcher
Materials R&D
Year Objective
Bias Q -Q & heat Q Q& toner Q sweep Q
Analysis dVox/dt J-V Vox then done with metal dot C-V dVox/dt J-V confirm F-N behavior Optical microscope Vfb Vox when Vsi=0 Cox = dQ/dV Vox Qmobile
Product type Logic DRAM Analog
Static Property
Dynamic Property
Vt (voltage needed for Power consumption (gate on-state) leakage during on-state) Storage cell storage capacitance Storage cell refresh rate
+ + + + + + + +
-
-
-
-
-E
+++++++ - - - - - - c
SiO2
+ - + p-Si + + + +
+
+
+
Ei Ef Ev + + + +
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KLA-Tencor Confidential
Review of MOS semiconductor physics

Quantox supports low-k development Quantifies film leakage characteristics Provides measurement of dielectric constant when used with ASET F5x

Software: V3.8.0 with features of Multi-calibrations, and 2 Active Jg index, Ultra EOT, ACTIV Qtot, ACTIV Vfb, ACTIV Dit, and more… KLA-Tencor Confidential
Vt (voltage needed for Amplification gain on-state)
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KLA-Tencor Confidential
MOS: Oxide Impurity Characterization
Surface Charge, Qsurf
+ +
Mobile Charge, Bulk Trapped Qm Charge, Qot + + + +
1969: C.J. Claus
First commercial system to combine corona, Kelvin probe, and light Office copier Deposit corona, Q, to hold toner
Use KP to measure how much Q was deposited
MOSFET transistor operation: Review
OFF when VG = 0
VG = 0
Gate Poly
+VDS Drain
Gate Source P-type Si (NMOS)
ID (mA/m)
VG > V T VG = V T VG = 0 VD (V)
ON when VG > VT
Quantox detects electrical defects in dielectrics or semiconductors:
Elemental contamination: Cu, Al, Ni, Zn, Na, Li, K, Fe, Co, O, N, P, Ca, etc.
Structural “contamination”: like near-surface crystal defects due to RTO that kill DRAM retention time
p-Si
If material is p-type, then „majority‟ carriers are positively charged holes
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KLA-Tencor Confidential
Review of MOS semiconductor physics
Depletion = a scarcity of majority carriers at the Si/SiO2 interface Here, we show a depleted p-type sample:
Gate Poly
+VDS Drain
Gate Source
ID (mA/m)
VG =+ VT
- - -
VG > V T VG = V T VG < V T VD (V)