EE121b HOMEWORK #3 SOLUTIONS
1. Base collector depletion width inside the base at small VBC (VBC=0):
, =
2 2
= 155
( + )
The part that is inside the base:
,
= 7
+
Base emitter depletion width:
, =
2 ( 2 )
= 24
( + )
Neutral Base width:
=
,
EE 121B HW1 Solution (Winter 2014)
1. ND=1015 cm-3
a) T=0, freeze-out, n=0, p=0, intrinsic
b) T=300K, n= ND=1015 (cm-3), p= ni2/ND=105 (cm-3), n-type
c) T=1000K, ni(T=1000K) > ni(T=300K) since ni is a strong function of temperature
ni N C NV exp( E g / 2k
EE 121B / Winter 2014 / Prof. Chui / UCLA
Homework #01, p.1
EE 121B Principles of Semiconductor Device Design
Winter 2014 Homework #01
(Due Date: Jan 21st, 2014, 12 pm in Boelter 6731)
Physical constants:
I. Electronic charge = 1.60 10-19 C
II. Vacuum Per
HW #2, Due April 23, 2009
(Assume room temperature in all problems except when it is specifically stated
otherwise. Also assume silicon as the semiconductor material with ni = 1 x l010cm-3)
1. We derived in the class the expression for the base-transport
EE121B Spring 09
Home Work #1
1. A silicon p-n-p transistor has impurity concentrations of 5x1019, 2x1018, and 1016 cm-3 in
the emitter, base, and collector, respectively. The emitter and base widths are 0.2 m and
0.15 m respectively. The device cross-sec
Using ni = 1010, kT/q=1.6 x 10-19
1. Show A
gm
rb 'e
g m ro
VA
.
VT
IC
VT
I C VA VA
VT I C VT
A gm (
ro rl
V
) g m ro A
ro rl
VT
2.
Vbe
rbc, ro are large, so we can neglect them.
ic g mVb 'e
ib
Vbe
Vbe sC b 'e Vbe sC b 'c
rb 'e
C b 'e Cb 'edep
h fe
EE121B Spring 09
Home Work #4
1) In the Bipolar transistor notes, we shows that in the common emitter configuration:
RL
C
B
v
rbb
B
E
with the equivalent circuit model for the BJT:
b
C b c
rbb
b
rbe
c
ib
C be
rbc
gm be
ro
e
the gm is given:
gm =
ic 1
=
*
EE121B Spring 2009 HW#3
1.
An n-p-n transistor has impurity concentrations of 1020 cm-3, 1018 cm-3 and 5X1016 cm-3 in
the emitter, base and collector regions respectively. Assume that the metallurgical base width,
WBM, is 150nm, the metallurgical emitter
EE 121B / Winter 2011 / Prof. Chui / UCLA
Homework #02, p.1
EE 121B Principles of Semiconductor Device Design
Winter 2014 Homework #02
(Due Date: Jan 28th, 2014, 12 pm in Boelter 6731)
Apply the same set of physical constants and general assumptions as in
