Download AKTU B-Tech 6th Sem 2016-2017 EEC013 Advanced Semiconductor Devces Question Paper

Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 6th Semester (Sixth Semester) 2016-2017 EEC013 Advanced Semiconductor Devces Question Paper

Printed Pages:2 Roll No.| l l l l I l l l l l EEC013
B.TECH.
THEORY EXAMINATION (SEM?VI) 2016-17
ADVANCED SEMICONDUCTOR DEVCES
Time : 3 Hours Max. Marks : 100
Note : Be precise in your answer. In case Ofnumerical problem assume data wherever not provided.
SECTION ? A
1. Attempt the following: 10 x 2 = 20
(a) What are the simple cubic, bee and fee structures?
(b) Why does semiconductor behave as an insulator at 0K?
(c) What is Fermi level? Write its significance.
(d) What is impurity and lattice scattering?
(e) What is the difference between drift and diffusion current?
(f) Define mobility of a carrier.
(g) Why is Hall effect useful?
(h) What is the significance of negative resistance in Tunnel diode?
(i) What are delays in IMPATT diode?
(i) What is solar cell?
SECTION ? B
2. Attempt any five of the following questions: 5 x 10 = 50
(a) Derive the condition for minimum conductivity of a semiconductor sample and
compare result at 300K with intrinsic conductivity. A Sample of Si is doped with 1017
phosphorous atoms/cm3. What hall voltage would you expect in a sample 100p m thick,
if IX=1mA, BZ=1kG=10'5 wb/cmz? What is high field effect in semiconductors?
(b) Derive the expression for Conductivity and Mobility and also the expression for
Diffusion of carriers in semiconductors.
(c) Derive the expression for carrier generation and recombination and High level injection
effect in Real diodes.
((1) Explain Trapping. Derive the Basic carrier transport equation for semiconductor device
operation.
(e) In a Si sample 1013 EHP/cm3 are created optically every microsecond with n0=1014/cm3
and tn=2psec and tp=lpsec. find steady state excess electron and hole concentrations
and also estimate separation between quasi Fermi levels by showing in band diagrams.
(f) Derive the expression for Electric field in Linear Graded Junction. In a very long p?type
Si bar with cross sectional area=0.5(:m2 and Na=1017/cm3, we inject holes such that the
steady state excess hole concentration is 5X1016/cm3 at X=O. Find hole current and
excess stored hole charge at 1000A. Assume pp: 500cm2/V-s and tp=10'10sec.
(g) An abrupt Si p?n junction (A=10'4cm2) has the following properties at 300K. p?
sideeNa=1017/cm3, tn=0.1us,pp=200cm2/v-s,pn=700;n?sideeNd=1015/cm3, tp=10us,
pn=l300, pp=450. The junction is forward biased by 0.5V. What is the forward current?
Reverse bias voltage: ?0.5V. Find Reverse Current.
(h) Explain I?V characteristics of Real diodes and also explain Breakdown mechanism in
p-n junction diode.

SECTION ? C
Attempt any two parts of the following questions: 2 x 15 = 30
What is Varactor diode? Explain its working with diagram. What are its advantages and
disadvantages and applications? Explain fill factor in solar cell.
Explain IMPATT Diode and its working. What is Transferred electron Mechanism?
What is Light emitting diode? Explain its working principle. What are the materials used in
LED? Explain its uses.