West Bengal Institute of Technology (WBIT) 2011-4th Sem B.Tech Electronics and Communications Engineering B_TECH ,Microelectroics and optoelectronics devices(ME),,ester,WBUT - Question Paper

GROUP-A
(Multiple option quesion)
1.Choose from the accurate options for any ten of the following: 1*10=10
i) DIBL occurs in
a) short channel devices
b) long channel devices
c) both of these devices
ii) V groove is produced for
a) anisotropic etching
b) isotropic etching
c) both of these.
iii) Schottky barrier diode can be used as
a) low noise amplifier
b) variable capacitor
c) power supply rectifier
d) level detector
iv) On modern electronics millimeterrs, a FET or MOSFET is preffered over BJT because
a) Ri is high
b) Ro is high
c) Ri is low
d) it is cheaper
v) The energy gap oa GaAs is
a) 1.12eV
b) 0.72eV
c)1.43eV
d) 1.44 eV
vi) Vertical power BJT off resistance should be
a) very low
b) very high
c) inlinite
d) like intrinsic semiconductor
vii) Si Anisotropic etchant is
a) HNA
b) KOH
c) HF
d) both (a) & (b)
viii) The condition to form the hetrojunction is
a) that the band gap of the semiconductor materials should be various
b) that teh work function should be various
c) both (a)&(b)
d) either (a)or(b)
ix) Charge coupled devices are used to
a) store the charge
b) transfer the charge
c) both (a)& (b)
d) none of these
x) In Schottky barrier diode, the current mechanism is due to
a) majority carrier
b) minority carrier
c) both (a)&(b)
d) none of these
xi) The radiative and non-radiative life time of an LED are 2.5ms and 60 ms respectively. The internal quantum eficiency is
a) 96%
b) 24%
c) 100%
d) 104%
xii)Hall voltage is proprotional to
a) velocity
b) magnetic field
c) both a & b and paralle; to velocity
d) both a & band perpendicular to the velocity
xiii) Most comonly used method for transduction in MEMS sensor is
a) Peizo-electric effect
b) change of capacitance effect
c) magnetic effect
d) any of these
xiv) Photodetector used in optical fibre is
a) p-i-n, APD
b) PIN, Gun DIode
c) APD, Gunn Diode
d) none of these
xv) The radiative and non-radiative lifetime os an LED are 2.5 ms and 6.0ms respectively. The internal quantum efficiency is
a) 96%
b) 24%
c) 100%
d) 104%



GROUP-B
( Short ans kind questions)
ans any 3 of the following: 3*5=15

Earning:   Approval pending.