ECE 445
Fall 2011
Midterm Exam II
Date: 11/22/11
Attempt any three
Time: 5:30 6:45pm
1. Using Boltzmann statistics calculate the position of the electron and hole quasiFermi
level when eh density of 1017cm3 is injected into intrinsic silicon at 300oK.
CARRIER TRANSPORT PHENOMENA
1. Drift Current
2. Diffusion Current (Diff. Current)
Figure 4.1 Typical random behavior of a hole in a semiconductor (a) without an
electric field and (b) with an electric field
Drift Current:
If a positive volume charge dens
ENERGY BAND DIAGRAM
Axis E = Energy
Axis K = Wave vectors
+ K Direction [100]
 K Direction [111]
For GaAs: Valency band minimum
Conduction band maximum
GaAs is direct bandgap semiconductor.
K=0
For Silicon: Valency band minimum
Conduction band maxi
CARRIER GENERATIONS AND RECOMBINATIONS
GENERATION: It is the process, whereby the electrons and holes
are created.
RECOMBINATION: It is process, whereby the electrons and
holes are annihilated by recombining each other.
SEMICONDUCTOR IN EQULIBRIUM:
Let G
THE SEMICONDUCTOR IN EQUILIBRIUM
CHARGE CARRIERS IN SEMICONDUCTOR
In semiconductor Charge Carriers: (1) Electrons (2) Holes
Current is the rate at which charge flows.
The current in a semiconductor is a function to number of
electrons in the conduction
CARRIER TRANSPORT PHENOMENA
1. Drift Current
2. Diffusion Current (Diff. Current)
Figure 4.1 Typical random behavior of a hole in a semiconductor (a) without an
electric field and (b) with an electric field
Drift Current:
If a positive volume charge dens
Metal Oxide Semiconductor
1. MOS two terminal and three terminal devices
2. Energy banddiagram
3. Electrical Parameters: Drainsource current,
threshold voltage, subthreshold voltage and
extrinsic parameters: transconductance, drain
conductance, and gat
1
2
3
4
5
6
The first and most
important one shows the
bandgap vs. the lattice
constant plus
information about the
band type. It is shown
below, with the IIVI
compounds included for
good measure:
7
bbbbb
8
9
10
DIAMOND LATTICE:
The basic structure for ma
CARRIER GENERATIONS AND RECOMBINATIONS
GENERATION: It is the process, whereby the electrons and holes
are created.
RECOMBINATION: It is process, whereby the electrons and
holes are annihilated by recombining each other.
SEMICONDUCTOR IN EQULIBRIUM:
Let G
CALIFORNIA STATE UNIVERSITY, NORTHRIDGE
DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING
FALL 2015
COURSE SYLLABUS
ECE445 INTRODUCTION TO SOLID STATE DEVICES
I. Instructor
 Somnath Chattopadhyay
 Office:
JD 3327 and Microelectronics Lab Room # JD1101

FALL 2011
Home Work
Assignment Date: 10/13/2011
1.
ECE 445
Due Date: 10/20/11
2.
3.
4.
5.
6.
7.
Individual Attempt Required
Please get advice in office hours
Make Mid Term Examination
Take Home Test
Assigned Date: 12/7/11
12/9/11
Due Date:
1. An ntype silicon sample has been doped with 10 15 phosphorous atoms cm3.
The donor energy level for P in Si is 0.045 eV below the conduction band
energy. (a) Estimate t
Make Mid Term Examination
Take Home Test
Assigned Date: 12/7/11
12/9/11
1.
Due Date:
An ntype silicon sample has been doped with 1015 phosphorous atoms cm3.
The donor energy level for P in Si is 0.045 eV below the conduction band
energy. (a) Estimate
Make Mid Term Examination
Take Home Test
Assigned Date: 12/7/11
Due Date: 12/9/11
1. An ntype silicon sample has been doped with 10 15 phosphorous atoms cm3. The donor
energy level for P in Si is 0.045eV below the conduction band energy. (a) Estimate th
ECE 445
Fall 2011
Midterm Exam II
Date: 11/22/11
Attempt any three
Time: 5:30 6:45pm
1. Using Boltzmann statistics calculate the position of the electron and hole quasiFermi
level when eh density of 1017cm3 is injected into intrinsic silicon at 300o
PN JUNCTION DIODE II
pn Junction Current:
Boundary Condition:
An expression for builtinvoltage (potential) has been derived as:
(8.1)
If we assume the complete ionization, the free electron can be estimated as
nn0 Nd
(8.2)
Where nn0 = Thermal equilibr