1. Which is the commonly used bulk substrate in nMOS fabrication?
a) silicon crystal
b) silicon-on-sapphire
c) phosphorus
d) silicon-di-oxide
Explanation: In nMOS fabrication, the bulk substrate used can be either bulk silicon or silicon-on-sapphire
2. In nMOS fabrication, etching is done using ____________
a) plasma
b) hydrochloric acid
c) sulphuric acid
d) sodium chloride
Explanation:In nMOS fabrication, etching is done using hydrofluoric acid or plasma. Etching is a process used to remove layers from the surface
3. Heavily doped polysilicon is deposited using ____________
a) chemical vapour decomposition
b) chemical vapour deposition
c) chemical deposition
d) dry deposition
Explanation: The polysilicon layer consists of heavily doped polysilicon deposited by chemical vapour deposition
4. In diffusion process ______ impurity is desired.
a) n type
b) p type
c) np type
d) none of the mentioned
Explanation: Diffusion is carried out by heating the wafer to high temperature and passing a gas containing the desired ntype impurity
5. Contact cuts are made in ____________
a) source
b) drain
c) metal layer
d) diffusion layer
Explanation:Contact cuts are made in the desired polysilicon area, source and gate. COntact cuts are those places where connection has to be made.
6. Interconnection pattern is made on ____________
a) polysilicon layer
b) silicon-di-oxide layer
c) metal layer
d) diffusion layer
Explanation: The metal layer is masked and etched to form interconnection pattern. The metal layer was formed using aluminium deposited over the formed surface.
7. SIlicon-di-oxide is a good insulator.
a) True
b) False
Explanation: SIlicon-di-oxide is a very good insulator so a very thin layer is required in the fabrication of MOS transistor.
8. _______ is used to suppress unwanted conduction.
a) phosphorus
b) boron
c) silicon
d) oxygen
Explanation: Boron is used to suppress the unwanted conduction between transistor sites. It is implanted in the exposed regions.
9. Which is used for the interconnection?
a) boron
b) oxygen
c) aluminium
d) silicon
Explanation: Aluminium is the suitable material used for the circuit interconnection or connecting two layers.
10. CMOS technology is used in developing which of the following?
a) microprocessors
b) microcontrollers
c) digital logic circuits
d) all of the mentioned
Explanation: CMOS technology is used in developing microcontrollers, microprocessors, digital logic circuits and other integrated circuits