B.TECH - Semester 3 solid state devices Question Paper 2020 (feb)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- Draw and explain the VI characteristics of PN junction diode.
- Explain the different types of capacitances associated with a p-n junction.
- A Si sample is doped with $10^{17} \mathrm{As}$ atoms $/ \mathrm{cm}^{3}$. What is the equilibrium hole concentration $p_{0}$ at 300 K ? Where is $\mathrm{E}_{\mathrm{F}}$ relative to $\mathrm{E}_{\mathrm{i}}$ ?
- Explain the effect of temperature on mobility.
- Draw and explain the energy band diagram of an Ohmic contact.
- Explain base width modulation with neat diagrams.
- Illustrate the minority carrier distribution in a PNP transistor in the active mode of operation.
- Define threshold voltage of MOS capacitor.
- Explain Sub-threshold conduction in MOSFET.
- Explain the principle of operation of UJT. P.T.O. Answer any two full questions from each module. Each question carries 10 marks.
- The Fermi level position in a Si sample at 300 K is 0.29 eV below $\mathrm{E}_{\mathrm{c}}$. Determine the carrier concentration and conductivity of the specimen. Given that $\mathrm{n}_{\mathrm{i}}=1.5 \times 10^{10} \mathrm{~cm}^{-3} . \mu_{n}=1350...
- Derive the expression for equilibrium carrier concentrations.
- Derive ideal diode equation.
- Define with expressions (i) Base transport factor (ii) Emitter injection efficiency (iii) Current transfer ratio (iv) Base to collector current amplification factor.
- Explain with neat diagrams. (i) Zener breakdown. (ii) Avalanche breakdown.
- A Schottky barrier diode is formed by depositing tungsten on $n$-type Si. If $N_{D}=10^{15} \mathrm{~cm}^{-3}, q \varphi_{m}=4.9 \mathrm{eV}, q \chi_{s}=4.15 \mathrm{eV}$ (electron affinity of silicon), determine at 300 K . (i) Built in Voltage (ii) ...
- What are the effects of real surfaces on the threshold voltage of a MOS capacitor? Derive the threshold voltage equation of a real MOS capacitor?
- (a) Draw and explain the drain characteristics of JFET.
- (b) An $n$ channel Si JEFT has $N_{a}=10^{19} \mathrm{~cm}^{-3}, N_{d}=10^{15} \mathrm{~cm}^{-3}$, and $a=4 \mu m$. Determine at 300 K (i) Pinch off voltage (ii) gate bias required to make thickness of undepleted channel width equal to $1 \mu \mathrm...
- (a) Explain the principle of operation of an IGBT.
- (b) Derive the expression of drain current of MOSFET. $$ \text { ( } 6 \times 10=60 \text { Marks) } $$