半导体导论翻译(精)

半导体导论翻译(精)

半导体导论 P124-125

CHAPTER 3 The Semiconductor in Equilibrium

(d) T = 400 K, N d = 0, N a = 1014 cm-3

(e) T = 500 K, N d = 1014 cm-3, Na = 0

3.37 Repeat problem 3.36 for GaAs.

3.38 Assume that silicon, germanium, and gallium arsenide each have dopant concentrations of Nd = 1X1013 cm-3 and Na = 2.5 x 1014 cm-3 at T=300K.For each of the three materials(a) Is this material n type or p type?(b) Calculate n0 and p0.

3.39 A sample of silicon at T =450K is doped with boron at a concentration 0f 1.5x1015cm-3and with arsenic at a concentration of 8 X 1014cm-3 .(a) Is the material n type or p type? (b) Determine the electron and hole concentrations .(c) Calculate the total ionized impurity concentration.

3.40 The thermal equilibrium hole concentration in silicon at T = 300 K is p0=2x1015 cm-3 .Determine the thermal-equilibrium electron concentration .Is the material n type or p type?

3.41 In a sample of GaAs at T = 200 K, we have experimentally determined that n0 = 5 p0 and that Na = 0. Calculate n0, p0, and N d.

3.42 Consider a sample of silicon doped at N d = 1014 cm-3 and Na = 0 Calcu1ate the majority-carrier concentration at (a) T = 300 K, (b) T = 350 K,(C ) T = 400 K

(d) T = 450 K, and (e) T = 500 K.

3.43 Consider a sample of silicon doped at N d = 0 and Na = 1014 cm-3 .Plot the majority-carrier concentration versus temperature over the range 200≤T≤500K.

3.44 The temperature of a sample of silicon is T = 300 K and the acceptor doping concentration is Na = 0. Plot the minority-carrier concentration (on a log-log plot) versus Nd over the range 1015≤N d≤1018 cm-3.

3.45 Repeat problem 3.44 for GaAs.

3.46 A particular semiconductor material is doped at N d = 2 x 1013 cm-3, Na = 0, and the intrinsic carrier concentration is ni = 2 x 1013cm-3. Assume complete ionization. Determine the thermal-equilibrium majority-and minority-carrier concentrations.

3.47 (a) Silicon at T = 300 K is uniformly doped with arsenic atoms at a concentration of 2 x 1016cm-3and boron atoms at a concentration of 1 x1013 cm-3. Determine the thermal-equilibrium concentrations of majority and

x1015cm-3 . Donor atoms are add forming an n-type compensated semiconductor such that the Fermi level is 0.215 eV below the conduction band edge .What concentration of donor atoms are added?

3.56 Silicon at T = 300 K is doped with acceptor atoms at a concentration of Na = 7 x1015cm-3. (a) Determine E f-E v. (b) Calculate the concentration of additional acceptor atoms that must be added to move the Fermi level a distance kT closer to the valence-band edge.

3.57 (a) Determine the position of the Fermi level with respect to the intrinsic Fermi level in silicon at T = 300 K that is doped with phosphorus atoms at a concentration of 1015cm-3. (b) Repeat part (a) if the silicon is doped with boron atoms at a concentration of 1015cm-3. (c) Calculate the electron concentration in the silicon for parts (a) and (b).

3.58 Gallium arsenide at T = 300 K contains acceptor impurity atoms at a density of 1015cm-3. Additional impurity atoms are to be added so that the Fermi level is 0.45 eV below the intrinsic level. Determine the concentration and type (donor or acceptor) of impurity atoms to be added.

3.59 Determine the Fermi energy level with respect to the intrinsic Fermi level for each condition given in Problem 3.36.

3.60 Find the Fermi energy level with respect to the valence band energy for the conditions given in Problem 3.37.

3.61 Calculate the position of the Fermi energy level with respect to the intrinsic Fermi for the conditions given in Problem 3.48.

Summary and Review

3.62 A special semiconductor material is to be “designed. ” The semiconductor

is to be n type and doped with 1 x 1015 cm -3donor atoms . Assume complete ionization and assume N a=0. The effective density of states functions are given by N c=N v=1.5x1019cm-3 and ate independent of temperature .A particular semiconductor device fabricated with this