ENEE 313 SAMPLE MIDTERM II
1. Consider a solar cell composed of a Schottky diode with transparent gates and a near
100% quantum eciency. Assume that the bulk recombination losses are small. Thus,
the main factor determine eciency is the fraction of photo
SAMPLE MIDTERM I SOLUTIONS ENEE313
MARTIN PECKERAR
I. CRYSTALLOGRAPHY
1. Dene, in some detail, the term crystal. 10
To quote from the supplementary tex posted on the blackboard site:
There are many ways to dene the term crystal. The most familiar way (pe
Bipolar Junction Transistor Concepts
Forward Active NPN BJT Operation
VC > VB > VE
Fundamentals
A BJT is often considered to be a current amplifier because a small current
entering the base will typically result in a large current into the collector. Or w
Current Components inside Bipolar Junction
Transistor (BJT)
NPN BJT
BJTIVcharacteristics
Last class we derived the current equations in forward active
for npn transistor
I C =I S e
recombination of holes and collectors
in base
qVBE
kT
qADn ni2
IS =
WB N A
HW 6
Due Thursday, March 14, 2013
Read sections 3.2.13.2.4, 3.3, 3.4,13.4.4, 4.1, 4.3 in S&B.
1) 3.2 (f(C) should be f(E)
2) 3.3. Also make a simple sketch indicating the relative positions of the Valence Band
maximum energy (Ev), Fermi Level (Ef), Dono
ENEE 313
HW 8
Due Thursday, April 11, 2013
Read 5.2, 5.3, 5.4 (quickly), 5.5.4
1) In class, we derived the expressions for the electric field and electrostatic potential
versus position in the Nside of the depletion region. For homework, derive these
exp
ENEE 313, Exam 2, 2010
Part I. (30)
1. Describe in words in terms of drift and diffusion how a PN junction diode works
in equilibrium, forward bias and reverse bias.
2. Sketch a PN junction and indicate how you would attach a battery for forward
bias and
ENEE 313
HW 7
Due Thursday, April 4, 2013
Read 4.1, 4.3.14, 4.4.14, 5.2 Note that the derivation of the diffusion process in the text
will differ from the presentation in class.
1) Derive the expression for the hole diffusion current density across a pl
ENEE 313
Homework 9
Due: Thursday. April 18, 2013
Reading: Class website notes on BJTs.
1) A Silicon PN junction is doped with Nd=5 x1016/cm3 and Na=1017/cm3, and has a
crosssection area of 100m x 100m. Assume that the diode can be considered to be
infin
ENEE 313
HW 1, Due Tuesday, Feb. 5, 2013
Read Sections 1.1, 1.2 and Chapter 2 in the Streetman and Banerjee (S&B)
Review the website link that allows you to view lattices of various orientations.
1) Consider the structure illustrated below, which might re
ENEE 313
Homework 10
Due April 25, 2013
Reading: Class website notes on BJTs.
1. A BJT has the structure and parameters below. Calculate and Assume forward
active operation.
a. Base Width = 0.5mu
b. Electron lifetime in base is 1x107sec
c. Base doping is
ENEE 313
HW 2, Due Thursday, Feb 14, 2013
Read Chapter 2, in S&B.
1. 2.5
2. 2.6 (Hint, the size of the smallest observable feature that can be seen with a microscope is
proportional to the wavelength.)
3. 2.11
4. Calculate the frequency of light emitted w
Derivation of MOSFET Threshold Voltage from the MOS Capacitor
ENEE 313 Notes
Prof. Neil Goldsman
Threshold voltage is the voltage applied between gate and source of a MOSFET
that is needed to turn the device on for linear and saturation regions of operati
DERIVATION OF MOSFET IDS VS. VDS + VGS
Derive the current expressions in the MOSFET:
Linear Region: ID = Cox W [(VGS VT H )VDS
L
2
VDS
]
2
W
Saturation Region: ID = Cox 2L (VGS VT H )2
1. Linear Region
Figure 1. Concentration Contours in Linear Region. A
Final Exam: ENEE 313
Part I (30pts):
A BJT has the emitter doped with NDE donors, the base with NAB acceptors, and the
collector doped NDC donors.
1. Is this an NPN or PNP transistor, why?
2. Describe qualitatively how a BJT works in forward active mode.
MIDTERM
I
ENEE 313.SPRING 2OII
Instructor: Professor Agis Iliadis Place: KEB
Question
l.
2.
3.
4.
5.
State the spatial part of
)
Date:
3/8lll Time:
3:304:45pm
50"/o
Schrodinger's equation for one dimension (x) and explain the physical
meaning of each ter
ENEE 313
Formula Sheet
I x I 0e x
d n
r n0 p0 n n 2
dt
dn x
J ndiff qDn
dx
dp x
J pdiff qDp
dx
J ndrift qn n x E x
J pdrift q p p x E x
E x
D
n
t
dV x
dx
kT
q
Dn
2 n n
x 2 n
p
2 p p
Dn
t
x 2
n
Ln Dn n
Lp Dp p
kT N A N D
for PN junction
ln
q
10
Chapter I
Models for IntegratedCircuit Active Devices
The breakdown voltage is calculated using
RI
=
LargeSignal Behavior of Bipolar Transistors
= r
in (1.24) to give
r
)
0
e(NA + N
=
5
x15x1O
2
1.04xlO
x9xlO
2x 1.6 x lO x 5 x lO x 1016
=
88V
V
C
La
Exam Study Practice
Do all the reading assignments.
Be able to solve all the homework problems
without your notes.
Redo the derivations we did in class on
your own.
Equations given: See Formula Posted
Exam Study Questions for Crystals
What is a cryst
Exam Study Guide
Emphasizes Homeworks 6 through 9
Exam covers assigned sections of Chps. 3,4 & 5. Exam will
also assume some basic information from the early part of
the semester. It will assume you know the basic
information from the earlier part of th
Final Exam: ENEE 313
Part I (30pts): A BJT has the emitter doped with NDE donors, the base with NAB
acceptors, and the collector doped NDC donors.
1. Describe qualitatively how a BJT works in forward active mode. Include the
various components of the curr
ENEE 313
HW 3, Due Thursday, February 21, 2013
Read Chapter 2 in S&B.
1) If an electron is in the ground state in an infinite potential well of length 1.0 nanometers,
calculate the probability of finding the particle in the region 0 < x < L/4). Compare th
ENEE 313
HW 4, Due Thursday. Feb 28, 2013
Read Chp. 2 in the textbook
1) Electrons with energy E are emitted from a filament and shot toward a barrier of potential
energy Vb. The barrier is sufficiently wide so that it can be approximated as infinitely wi
ENEE 313
HW 5, Due , March 7, 2013
Read sections 3.1, 3.2.13.2.4, 3.3, 3.4 in S&B.
1) Questions about Band Structure of Solid Crystals
a. Explain how energy bands arise in a crystal by bringing Avogadros number of atoms
together. How many quantum states
Current Components inside Bipolar Junction
Transistor (BJT)
NPN BJT
BJTIVcharacteristics
Last class we derived the current equations in forward active
for npn transistor
I C =I S e
recombination of holes and collectors
in base
qVBE
kT
qADn ni2
IS =
WB N A
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.313
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Electrons in the Periodic Potential of a Crystal
The discussion of the properties of metals in the previous chapter was based
on a freeelectron model (or rather: a gas of neutral fermionic particles) in an
empty box. The classical Drude model and the
BJT structure
heavily doped ~ 10^15
provides the carriers
lightly doped ~ 10^8
lightly doped ~ 10^6
note: this is a current of electrons (npn case) and so the
conventional current flows from collector to emitter.
BJT characteristics
BJT characteristics
BJ