ECSE-2210 Microelectronics Technology
Class Activity 13 Solution
1. Answer the following questions. Give reasons.
2K
W = s 0
q
1/ 2
NA + ND
(Vbi VA )
N N
A D
a. In a p+-n junction, most of the depletion layer will be in the (choose one: n-side o

ECSE-2210 Microelectronics Technology
Fall 2003 Homework 3
Due Date: September 16, 2003
Reading Assignment: Pages 74-104 Visit: http:/jas2.eng.buff alo.edu/applets/index.html
to view some related applets.
1. A silicon sample maintained at 300 K under ther

ECSE-2210 Microelectronics Technology
Homework 4
Reading Assignment: Pages 74-104
1. A silicon sample maintained at 300 K under thermal equilibrium has a non-uniform doping
concentration profile, such that the electron concentration, n, varies linearly fr

ECSE-2210 Microelectronics Technology
Class Activity 13 Solution
1. Answer the following questions. Give reasons.
2K
W s 0
q
1/ 2
NA ND
Vbi VA
NN
AD
a. In a p+-n junction, most of the depletion layer will be in the (choose one: n-side or pside) of

ECSE-2210 Microelectronics Technology
Class Activity 19 Solution
1. In a BJT, indicate what happens (increase, decrease or no-effect: choose one and
understand why):
a. to if we increase the emitter doping?
Increases. It is the fraction of emitter current

ECSE-2210 Microelectronics Technology
Class Activity 20 Solution
1. The figure below shows the minority carrier concentrations in the emitter, base and
the collector region of an npn transistor. Answer the following questions. Most
questions do not need a

ECSE-2210 Microelectronics Technology
Class Activity 17 Solution
1. What is the root cause of the delay in switching from the on-state to the off state?
There are stored minority carriers in the quasi-neutral region immediately adjacent to
the depletion r

ECSE-2210 Microelectronics Technology
Class Activity 22 Solution
1. Explain what is meant by delta-approximation?
The accumulation charges and the inversion charges reside in an extremely narrow portion of
the semiconductor immediately adjacent to the oxi

ECSE-2210 Microelectronics Technology
Class Activity 21 Solution
1. Following are five figures showing charge density plots in ideal metal-oxide Si (p-type)
structures. Identify whether the voltages applied to the metal gate are VG < 0 or VG < 0 or
VG = 0

ECSE-2210 Microelectronics Technology
Class Activity 23 Solution
1. The energy band diagram for an ideal MOS-capacitor is shown below (xox = 0.2 m). The
applied gate voltage causes band bending such that EF = Ei at the Si-SiO2 interface. Answer
the follow

ECSE-2210 Microelectronics Technology
Class Activity 15 Solution
1. Consider a planar p+-n Si step junction diode with an n-side doping of ND = 1015 cm3 at
T = 300 K.
a. Estimate the approximate breakdown voltage VB of the diode.
You have to read this off

ECSE-2210 Microelectronics Technology
Class Activity 16 Solution
1. What is the physical origin of the junction capacitance (or depletion layer
capacitance)?
The in and out movement of the majority carriers about the steady state depletion
width in respon

ECSE-2210 Microelectronics Technology
Class Activity 18 Solution
1. The base region in a BJT is narrow. What is the precise definition of narrow?
The carriers emitted by the emitter need to reach the collector before they can
recombine in the base. Theref

ECSE-2210 Microelectronics Technology
Class Activity 12 Solution
1. Shown below is the electric field profile in the depletion region of a semiconductor pn junction in thermal equilibrium. Answer the following questions with explanations.
E
0.1
0
0.5
1.0

ECSE-2210 Microelectronics Technology
Class Activity 10 Solution
1. The equation below is called minority carrier diffusion equation for electrons.
nP
2 n P n P
= DN
+ GL
t
n
x 2
(a) Why is it called a diffusion equation?
The E-field is assumed to be zer

ECSE-2210 Microelectronics Technology
Class Activity 11 Solution
1. A Si step junction maintained at room temperature is doped such that EF = EV on the
p-side and EF = EC - 4kT on the n-side.
a. Draw the equilibrium energy band diagram for this junction.

ECSE-2210 Microelectronics Technology
Class Activity 9 Solution
1. A Si slab of thickness 100 m is illuminated from one side with light of energy 1.2 eV.
Calculate the wavelength of the light. Calculate the fraction of light intensity that is
transmitted

ECSE-2210 Microelectronics Technology
Class Activity 8 Solution
1. Name three generation and three recombination processes. Which one is more
common in Si and Ge? Which one is more common in GaAs?
Carrier generation by Band-to-band transitions, carrier ge

ECSE-2210 Microelectronics Technology
Homework 2
1. The bonding model for a semiconductor is explained in Figs 2.3 and 2.4 in the textbook.
a. Draw the bonding model for GaAs depicting the removal of one Ga and one As atom.
b. Redraw the bonding model sho

ECSE-2210 Microelectronics Technology
Homework 1
1. Problem 1.13 in text. Treating atoms as rigid spheres with radii equal to one-half the distance
between nearest neighbors, find the ratio of the volume occupied by the atoms to the total
available volume

ECSE-2210 Microelectronics Technology
Class Activity 2
(Refer to next page for values of some physical constants)
1. A voltage of 10V is applied to point B with respect to point A in the figure below. Assume C
is in the middle. If an electron at rest is p

ECSE-2210 Microelectronics Technology
Class Activity 4
1) Write down the word definition of gc(E) and gv(E).
2) Calculate the numerical value (in units of cm3) of the following integral (assume Si). This
should not take more than 30 seconds.
EC top
g c (

ECSE-2210 Microelectronics Technology
Class Activity 3
1) Intrinsic Si has 1 1010 cm3 electrons in its conduction band at 300 K. What will be the
number of holes in the valence band?
2) Consider three intrinsic semiconductors: Ge, Si and GaAs.
a. Which on

ECSE-2210 Microelectronics Technology
Class Activity 1
1. Quick Quiz (see problem 1.1 in textbook)
a. Name one elemental semiconductor and one compound semiconductor.
b. What is the difference between a crystalline and polycrystalline material?
c. Give a

ECSE-2210 Microelectronics Technology
Class Activity 6
1. Short Answer Questions.
(a) What is the electric field inside the Si bar shown below? What is its direction?
10V
0.1 cm
(b) How long does it take on average for an electron to drift 1 m in pure Si

ECSE-2210 Microelectronics Technology
Class Activity 5
Assume T = 300 K for all your calculations. Assume ni = 1010 cm-3 at 300 K for Si.
1) Explain what degenerate and non-degenerate semiconductors mean.
2) Calculate the numerical value of the following

ECSE-2210 Microelectronics Technology
Homework 2 Solution
1. a) The removal of the column III Ga atom with three valence electrons leaves five dangling
bonds in the vicinity of the vacancy. The removal of the column V As atom with five valence
electrons l

ECSE-2210 Microelectronics Technology
Homework 1 Solution
1. a) In the simple cubic lattice the nearest-neighbor distance is a, where a is the side length of
the cube, and the atomic radius r is therefore a/2. Moreover, there is one atom per unit cell.
Th

ECSE-2210 Microelectronics Technology
Homework 10
Reading list: Chapter 16
1. An ideal MOS-capacitor has xox= 0.1 m, ND = 1015 cm3, and an area A = 103 cm2.
a. Calculate F in units of kT/q and in Volts.
b. Calculate W when S = 2F.
c. Calculate ES when S =