Quiz #7
Student Name: _
Student ID: _
A light beam is illuminated on the surface of a silicon wafer, generating excess
carriers p0 at the surface (x=0). We assume there is no external generation inside
the wafer. The thickness of the wafer is W. At the su
Quiz #5
Name: _
Student ID: _
1. Suppose the ionization energy of donors in silicon is 0.04eV. The donor concentration is 10 15cm-3.
At what temperature will the donor ionization rate is (a) 90%, (b) 50%, (c) 10%, (d)1%, (e)1%.
Accordingly, what is the el
p-n junction under forward bias
q (Vbi- VR)
q VR
q
=qV
q Vbi o qVVF
qVo - qV-V )
q(Vbi F
V>0: the bias is called POSITIVE or Forward,
if the polarity is opposite to the built-in barrier.
Typical notation: VF. Forward bias REDUCES the potential barrier
V<0
VE320 Summer 2015
Introduction to Semiconductor Devices
Instructor: Yaping Dan
[email protected]
Lecture 15 Metal-Insulator-Semiconductor
MIS structure: work function
Metal
SiO2
Metal
oxide
semiconductor
Vacuum level
Ws
Vg
p- Si
Wm
Vg = 0
eb
EF
Flat
VE320 Summer 2015
Introduction to Semiconductor Devices
Instructor: Yaping Dan
[email protected]
Lecture 4 Band Structure and Effective Mass
Outline
Band structure in 2D k-space
Band structure in 3D k-space
Effective mass of electrons
2
Previousl
1. The Fermi level in the p-type regin is given by
The Fermi level in the p-type region is given by
EFp = EV KT ln(
p
1017
) = EV 0.026 ln(
) = EV + 0.113eV
NV
7.72 1018
The Fermi level in the n-type region
EFn = EC + KT ln(
n
1015
) = EC + 0.026 ln(
) =
HW_Problems_3_soln
1. The avg energy of an electron:
E=
E P( E )d E
0
P(E) Probability of finding the e with energy of E
=
E
2
( kT )
E
3
2
3
20
exp(
E
)dE
kT
Using functions: ( x) = t t ( x 1) dt
e
0
1
( )=
2
(x+1)=x (x)
3
This gives E = kT
2
2. The
Quiz #9
Student Name: _
Student ID: _
1. Can you explain in your own words how a pn junction is formed after a p-type semiconductor is
in contact with an n-type semiconductor? When the voltage bias on the pn junction sweeps from
negative to positive, why