文档来源为:从网络收集整理.word版本可编辑.欢迎下载支持.
Chapter 7
7.1
(a)
?2?10152?1015? (i)Vbi??0.0259?ln??
102???1.5?10? ?0.611V
?2?10152?1016? (ii)Vbi??0.0259?ln??
102???1.5?10? ?0.671V
?2?10152?1017? (iii)Vbi??0.0259?ln??
102???1.5?10? ?0.731V (b)
?2?10172?1015? (i)Vbi??0.0259?ln??
102???1.5?10? ?0.731V
?2?10172?1016? (ii)Vbi??0.0259?ln??
102???1.5?10? ?0.790V
?2?10172?1017? (iii)Vbi??0.0259?ln??
102???1.5?10? ?0.850V
_______________________________________ 7.2
Si: ni?1.5?1010cm?3
???????????????????????? Ge: Vbi?0.432V GaAs: Vbi?1.28V
_______________________________________ 7.3
(a) Silicon (T?300K)
For Na?Nd?1014cm?3; Vbi?0.4561V
?1015 ; ?0.5754V
?1016 ; ?0.6946V
?1017 ; ?0.8139V (b) GaAs (T?300K)
For Na?Nd?1014cm?3;
????????????Vbi?0.9237V
?1015 ; ?1.043V ?1016 ; ?1.162V ?1017 ; ?1.282V (c) Silicon (400 K), kT?0.034533 ni?2.38?1012cm?3
For Na?Nd?1014cm?3;
Ge: ni?2.4?1013cm?3 GaAs: ni?1.8?106cm?3 ?NaNd Vbi?Vtln??n2i?Vt?0.0259V
?? and ?? (a)Nd?1014cm?3, Na?1017cm?3' Then Si: Vbi?0.635V Ge: Vbi?0.253V GaAs: Vbi?1.10V (b)Nd?5?1016cm?3, Na?5?1016cm?3
Vbi?0.2582V
?1015 ; ?0.4172V
?1016 ; ?0.5762V
?1017 ; ?0.7353V GaAs(400 K), ni?3.29?109cm?3
For Na?Nd?1014cm?3;
Si: Vbi?0.778V Ge: Vbi?0.396V GaAs: Vbi?1.25V (c)Nd?1017cm?3, Na?1017cm?3 Si: Vbi?0.814V
Vbi?0.7129V
?1015 ; ?0.8719V ?1016 ; ?1.031V ?1017 ; ?1.190V
_______________________________________ 7.4
(a) n-side or
1文档来源为:从网络收集整理.word版本可编辑.
文档来源为:从网络收集整理.word版本可编辑.欢迎下载支持.
?0.695V
_______________________________________ 7.7
200 K; kT?0.017267; ni?1.38cm?3 300 K; kT?0.0259; ni?1.8?106cm?3
400 K; kT?0.034533; ni?3.28?109cm?3 For 200 K;
?1.257V For 300 K;
?1.157V For 400 K;
?1.023V
_______________________________________ 7.8
So Nd?3Na
2?1.5?1010 or 3Na EF?EFi?0.3294eV
p-side or
EFi?EF?0.4070eV (b) or
Vbi?0.7364V (c) or
Vbi?0.7363V (d) or
xn?0.426?10?4cm?0.426?m Now or
xp?0.0213?10?4cm?0.0213?m We have or
?max?3.29?104V/cm
_______________________________________ 7.5
(a) n-side or
EF?EFi?0.3653eV p-side or
EFi?EF?0.3653eV (b) or
Vbi?0.7306V (c) or
Vbi?0.7305V (d) or
xn?0.154?10?4cm?0.154?m By symmetry
xp?0.154?10?4cm?0.154?m Now or
?max?4.75?104V/cm
_______________________________________ 7.6
?EF?EFi?? (b) Nd?niexp??kT?
?? or Nd?1.98?1016cm?3 or Na?5.12?1015cm?3
(c)
??2?0.710?exp??
0.0259?? which yields Na?7.766?1015cm?3
Nd?2.33?1016cm?3 ?xn?9.93?10?6cm or xn?0.0993?m ?2.979?10?5cm or xp?0.2979?m
Now
?3.58?104V/cm (a) From part (a), we can write which yields Na?8.127?1015cm?3
Nd?2.438?1016cm?3 ?1.324?10?5cm or xn?0.1324?m
?3.973?10?5cm or xp?0.3973?m
?4.45?104V/cm
_______________________________________ 7.9
or
Vbi?0.635V (b) or
xn?0.8644?10?4cm?0.8644?m Now or
2文档来源为:从网络收集整理.word版本可编辑.
文档来源为:从网络收集整理.word版本可编辑.欢迎下载支持.
xp?0.08644?10?4cm?0.08644?m (c) or
?max?1.34?104V/cm
_______________________________________ 7.10
?2?10174?1016? (a) Vbi??0.0259?ln??
102???1.5?10? ?0.80813V
(b)Vbi increases as temperature decreases
AtT?300K, we can write
At T?287K, kT?0.024778eV So ni2?2.780?1019 Then
?0.82494V We find
_______________________________________ 7.11
Using the procedure from Problem 7.10, we
can write, for T?300K, At T?300K,
?0.68886V
For Vbi?0.550V, ?T?300K
xp?2.43?10?3cm (d) or
?max?3.75?102V/cm
_______________________________________ 7.14
Assume silicon, so or
(a)Nd?8?1014cm?3, LD?0.1447?m (b)Nd?2.2?1016cm?3,
??????LD?0.02760?m
(c)Nd?8?1017cm?3,
At T?380K, kT?0.032807eV Also Then
?0.5506V ?0.550V
_______________________________________ 7.12
(a) For Nd?1016cm?3, or
EF?EFi?0.3473eV
For Nd?1015cm?3 or
EF?EFi?0.2877eV Then or
Vbi?0.0596V
_______________________________________ 7.13 or
Vbi?0.456V (b) or
xn?2.43?10?7cm (c) or
LD?0.004577?m Now
(a)Vbi?0.7427V (b)Vbi?0.8286V (c)Vbi?0.9216V Also Then
(a)xn?1.096?m (b)xn?0.2178?m (c)xn?0.02730?m Now
L (a)D?0.1320
xn (b) (c)
LD?0.1267 xnLD?0.1677 xn_______________________________________ 7.15
We find (a) (i) For
Na?1017,Nd?1014;Vbi?0.6350V
(ii) ?1015; ?0.6946V
(iii) ?1016; ?0.7543V
(iv) ?1017; ?0.8139V (i) ForNa?1017,
Nd?1014; ?max?0.443?104V/cm
(ii) ?1015;
?1.46?104V/cm
3文档来源为:从网络收集整理.word版本可编辑.
文档来源为:从网络收集整理.word版本可编辑.欢迎下载支持.
(iii) ?1016; ?4.60?104V/cm
(iv) ?1017; ?11.2?104V/cm (b) (i) For
Na?1014,Nd?1014;Vbi?0.4561V
(ii) ?1015; ?0.5157V
(iii) ?1016; ?0.5754V
(iv) ?1017; ?0.6350V (i) ForNa?1014,
Nd?1014;?max?0.265?104V/cm (ii) ?1015; ?0.381?104V/cm
(iii) ?1016; ?0.420?104V/cm
(iv) ?1017; ?0.443?104V/cm
(b) ?max increases as the doping increases, and the electric field extends further into the low-doped side of the pn junction.
_______________________________________ 7.16
?0.6767V (i) For VR?0, ?9.452?10?5cm or W?0.9452?m (ii) For VR?5V,
?2.738?10cm or W?2.738?m (i)For VR?0,
2?0.6767??max??1.43?104V/cm ?40.9452?10 (ii)For VR?5V,
2?0.6767?5??max??4.15?104V/cm ?42.738?10_______________________________________ 7.17
?0.8081V (b)
?4 ?0.2987?10?4cm or xn?0.2987?m ?5.97?10?6cm or xp?0.0597?m ?0.3584?10?4cm or W?0.3584?m
Also W?xn?xp?0.3584?m
2?Vbi?VR?2?0.8081?2.5? ?W0.3584?10?4 ?1.85?105V/cm ?5.78?10?12F or C?5.78pF
_______________________________________ 7.18
We find
?Nd?2.684?1015cm?3
(c) ?max? Na?2.147?1017cm?3 (b)
?2.262?10?4cm or xn?2.262?m ?2.83?10?6cm or xp?0.0283?m
2?Vbi?VR?
W ?9.38?104V/cm
(c) ?max???e?sNaNd(d) C????????2V?VN?NbiRad??1/2
C??4.52?10?9F/cm2
_______________________________________ 7.19
?0.02845V C??3Na??3Na??? So ??3?1.732
C??Na??Na?(c) For a larger doping, the space charge width narrows which results in a larger capacitance.
_______________________________________ 7.20 or
Vbi?0.766V Now or or so that
?Vbi?VR??73.53V which yields
1/24文档来源为:从网络收集整理.word版本可编辑.
文档来源为:从网络收集整理.word版本可编辑.欢迎下载支持.
?1.162V So
Vbi?VR2C??VR1??
C??VR2?Vbi?VR1 VR?72.8V
or
Vbi?0.826V We have so that
?Vbi?VR??8.008V which yields VR?7.18V or
Vbi?0.886V We have so that
?Vbi?VR??1.456V which yields VR?0.570V
_______________________________________ 7.21 (a) or
We find
?10181015?VbiA??0.0259?ln???0.7543V
102???1.5?10?
?10181016?VbiB??0.0259?ln???0.8139V
102???1.5?10? We find or (b) or (c) or
_______________________________________ 7.22
(a) We have or
For VR?10V, we find or
Vbi?1.137V (b) Then Now so
We can then write which yields
Na?1.23?1016cm?3 and
Nd?3.07?1015cm?3
_______________________________________ 7.23
which yields VR2?2.58V
_______________________________________ 7.24
?0.6889V (i) For VR?0, C?7.567pF (ii) For VR?5V, C?2.633pF ?1.157V (i) For VR?0,
C?6.178pF (ii) For VR?5V,
C?2.678pF
_______________________________________ 7.25
?0.7543V
C?4.904?10?12F
?3.306?10?3H?3.306mH (b)
(i) For VR?1V, C?12.14pF ?7.94?105Hz?0.794MHz (ii) For VR?5V, C?6.704pF
?1.069?106Hz?1.069MHz _______________________________________ 7.26
Let Vbi?0.75V ?Nd?1.88?1016cm?3
?Nd?3.01?1015cm?3
_______________________________________ 7.27
By trial and error,
Nd?1.504?1015cm?3, Na?6.016?1015cm?3, Vbi?1.10V (a) From part (a),
By trial and error,
Nd?2.976?1015cm?3, Na?1.19?1016cm?3,
Vbi?1.135V
_______________________________________ 7.28 or
Vbi?0.5574V (b)
????????????5文档来源为:从网络收集整理.word版本可编辑.
半导体物理与器件第四版课后习题答案7
