Bihar engineering university electrical and electronics branch previous year question solution is provided.
1. Answer any questions : seven of the following
(a) 1 eV is how many joules of energy?
(b) What is diffusion capacitance?
(c) Define drift velocity.
(d) What is a degenerate semiconductor?
(e) The forward bias current is associated with what type of carrier activity?
(j) Define storage delay time.
(g) Why is the width of the base region kept very small as compared to other regions in BJTs?
(h) Why are enhancement mode MOSFETS preferred over depletion mode MOSFETs in fabrication of integrated circuits?
(i) Do ohmic contacts reduce the built-in voltage drop across a junction?
(j) What is the mathematical definition of (i) drain conductance and (ii) trans- conductance?
SEMICONDUCTOR PHYSICS PDF SOLUTION 200 IS PROVIDED BELOW
- (a) The probability that a state is filled at the conduction band edge (Ec) is precisely equal to the probability that a state is empty at the valence band edge (Ey). Where is the Fermi level located?
(b) Name the two dominant carrier scattering mechanisms in non- degenerately doped semiconductors of device quality.
(c) Using R-G statistics, explain the process of photo-generation.
- (a) What is the root cause for the delay in switching from the on state to the off state?
(b) What is special about the electrical and physical properties of a step recovery diode?
(c) Draw the energy band diagram characterizing an n-p-n transistor under equilibrium conditions. Take the transistor regions to be uniformly doped and assume a standard doping profile where the emitter doping>>base doping>collector doping. - (a) Explain the Ebers-Moll model with suitable diagram and associated expressions.
(b) Explain the geometrical effects- (i) emitter area collector area and (ii) series resistance.
(c) Explain the construction and V characteristics of Zener diode.
6. (a) Draw the energy band diagram for ideal MS contact between a metal and n-type semiconductor, if omos. Establish an expression for the barrier height of this MS contact
7.(a) Referring to the current voltage characteristics of MOSFET, what exactly is the saturation region of operation?
(b) What exactly is a ‘wide base’ diode?
(c) Derive an expression for the threshold voltage of a MOS transistor.
8.(a) Explain the construction and working principle of unijunction transistor (UJT). Draw its equivalent simplified model. What do you understand by intrinsic stand-off ratio?
(b) Explain the construction and working principle of silicon controlled rectifier (SCR). Draw its equivalent simplified model along with I-V characteristics. How do we turn ‘OFF’ the SCR?
9.(a) Explain the construction and working principle of a PIN photodiode.
(b) Explain (i) absorption, (ii) spontaneous emission and (iii) stimulated emission using E-K diagram.
(c) Explain the construction and working principle of a solar cell.
SEMICONDUCTOR PYQ SOLUTION 2022 PDF = DOWNLOAD
Semiconductor question paper 2022 pdf = Download
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