Semiconductor Physics and Devices: Basic Principles, 4th edition Chapter 5
By D. A. Neamen Problem Solutions
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Chapter 5
5.1 (a)
??1?1e???19??? nNd1.6?10?1300?1015 ?4.808?-cm
(b) ??11??4.8077?0.208(?-cm)?1
_______________________________________ 5.2
??e?pNa
or N.80a??1e??10?19??380? p?1.6? ?2.96?1016cm?3
_______________________________________ 5.3 (a) ??e?nN?d 10?1.6?10?19??nNd
From Figure 5.3, for N16d?6?10cm?3 we find ?2n?1050cm/V-s which gives ???1.6?10?19??1050??6?1016? ?10.08(?-cm)?1
(b) ??1e?N pa 0.20??11.6?10?19??
pNa From Figure 5.3, for Na?1017cm?3 we find ?p?320cm2/V-s which gives
???11.6?10?19??320??1017??0.195?-cm
_______________________________________ 5.4
(a) ??1e? pNa 0.35??11.6?10?19??
pNa From Figure 5.3, for Na?8?1016cm?3 we find ?p?220cm2/V-s which gives
????11.6?10?19?220??8?1016?
?0.355?-cm (b) ??e?nNd
120??1.6?10?19??nNd From Figure 5.3, for
Nd?2?1017cm?3, then ?n?3800cm2/V-s which gives
???1.6?10?19??3800??2?1017?
?121.6(?-cm)?1
_______________________________________ 5.5
R??LLLA??A??e? nNd?A or ?n?L?eNd?RA
????2.51.6?10?192?1015??70??0.1? ?1116cm2/V-s
_______________________________________ 5.6
(a) n16o?Nd?10cm?3 and
p?n2i??1.8?106?2?3.24?10?4ocm?3n16 o10 (b)
J?e?nno?
For GaAs doped at Nd?1016cm?3, ?n?7500cm2/V-s Then
J??1.6?10?19??7500??1016??10? or
J?120A/cm2 (b) (i) po?N?3a?1016cm
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Semiconductor Physics and Devices: Basic Principles, 4th edition Chapter 5
By D. A. Neamen Problem Solutions
______________________________________________________________________________________
n?n2iop?3.24?10?4cm?3 o (ii) For GaAs doped at N?1016cm?3a, ?p?310cm2/V-s
J?e?ppo? ? ? ?
?1.6?10?19?310?1016??10? or
J?4.96A/cm2
_______________________________________ 5.7 (a) V?IR?10??0.1?R or
R?100? (b)
R?LL?A???RA or
??10?3???0.01(?-cm)?1?100?10?3 (c) ??e?nNd or
0.01??1.6?10?19??1350?Nd Then
Nd?4.63?1013cm?3
(d)
??e?ppo
or
0.01??1.6?10?19??480?po Then
p3o?1.30?1014cm??Na?Nd So
N14a?1.30?10?1015?1.13?1015cm?3 Note: For the doping concentrations obtained, the assumed mobility values are valid.
_______________________________________ 5.8
(a) R?LL?A??e? pNa?A
For Na?2?1016cm?3, then ?2p?400cm/V-s
R???0.075?1.6?10?19??400??2?1016??8.5?10?4? ?68.93? I?V2R?68.93?0.0290A or I?29.0mA (b) R?L?R??68.93??3??206.79?
I?VR?2206.79?0.00967A or I?9.67mA (c) J?epo?d
For (a), J?29.0?10?328.5?10?4?34.12A/cm Then ??J?34.12dep?10?19??2?1016? o1.6? ?1.066?104cm/s For (b), J?9.67?10?38.5?10?4?11.38A/cm2 ??11.38d?1.6?10?19??2?1016?
?3.55?103cm/s
_______________________________________ 5.9 (a) For Nd?2?1015cm?3, then
?2n?8000cm/V-s
R?VI?525?10?3?200? R?L?e??A
nNd or L??e?nNd?RA ?
?1.6?10?19??8000??2?1015??200??5?10?5? ?0.0256cm
(b)
J?IA?eno?d 2
Semiconductor Physics and Devices: Basic Principles, 4th edition Chapter 5
By D. A. Neamen Problem Solutions
______________________________________________________________________________________
or ?Id?A?en? o ????25?10?35?10?51.6?10?19??2?1015? ?1.56?106cm/s
(c) I??eno?d?A
?
?1.6?10?19??2?1015??5?106??5?10?5? ?0.080A or I?80mA _______________________________________
5.10 (a)
??VL?31?3V/cm ????104dn???n?d??3 or ?2n?3333cm/V-s (b) ?d??n???800??3?
or
?d?2.4?103cm/s
_______________________________________
5.11 (a) Silicon: For ??1kV/cm, ?d?1.2?106cm/s Then
td??10?41.2?106?8.33?10?11t?s d For GaAs: ?d?7.5?106cm/s Then tdt???10?4.5?106?1.33?10?11s d7(b) Silicon: For ??50kV/cm, ?d?9.5?106cm/s
Then
t10?4 t?5?10?1.05?10?119.6s For GaAs: ?d?7?106cm/s
Then tt?10?47?106?1.43?10?11s _______________________________________ 5.12
??1?1e??? nno?e?ppoe?n??pni(a) N?3a?Nd?1014cm ??n?1350cm2/V-s ?p?480cm2/V-s ????11.6?10?19?1350?480??1.5?1010? ?2.28?105?-cm
(b) Na?N16d?10cm?3 ??n?1250cm2/V-s
?2p?410cm/V-s
????11.6?10?19?1250?410??1.5?1010? ?2.51?105?-cm (c) N?3a?Nd?1018cm ??n?290cm2/V-s
?p?130cm2/V-s
????11.6?10?19?290?130??1.5?1010? ?9.92?105?-cm
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半导体物理与器件第四版课后习题答案5
