M.Sc. I (Semester II) (CBCS) Examination, 2017
PHYSICS
MICROELECTRONICS
Day Date: Saturday, 22-04-2017 Max. Marks: 70
Time: 02.30 AM to 05.00 PM
Instruction Question 1 and 2 are compulsory
Attempt any Three from Q.3 to Q.7
Use of non-programmable calculator is allowed
All questions carry equal marks.
Q.1 Choose the correct answer 6
In Czochralski crystal growth process, the material are heated up to
9500c 14200c 10000c 12000c
The coating material used for the photo etching process along with
its thickness is,
Kodak photoresist (5000-10000Å)
Kodak photo etchant (1000-5000
Kodak photoresist (1000-5000
Kodak photo etchant (500-1000
An example of for deep UV photo resist is,
Poly-Methyl methacrylate (PMMA) Sodium Hydeoxide
Ammonium Hydroxide Potessium Chloride
The density of silicon atoms in the silicon crystal is,
5x1022 atoms/cm3 5x10-22atoms/ cm3
5x1022 atoms/ m3 none of these
The standard Ficks law of diffusion is given by,
j j
j
none of the mentioned
The CMOS process has the advantage over NMOS because
Low power dissipation Minimum sensitivity to the load
High packing density All of the mentioned
Page 2 of 2
State True or False 8
In the Silicon crystal structure, the defects shall not cause any
influence the optical, electrical and mechanism properties.
Oxidation provides extreme hard protective coating, thus protecting
against contamination.
In ion implantation technique, accelerating, potential and the beam
current are electrically controlled from outside.
GaAs belongs to the III IV compound semiconductors and are
suitable for opto=electronic devices and high =-speed ICs
Aluminum forms low resistance and therefore, it is suitable material
for the ohmic contact especially for p-type silicon and heavily doped
n-type silicon
Boron is a type material, whereas Phosphorous is an p-type
material
The maximum lead available in a metal can IC package is 12.
NMOS technology is preferred more than PMOS technology
Q.2 Write short notes on: 14
The environment for the VLSI technology
Growth kinetics of the epitaxial process
Characteristics of the good resist
Q.3 List Epitaxial defects and discuss any one in detail 06
With neat sketch, describe the MBE technique in detail. 08
Q.4 Write a note on optical lithography technique 06
Write necessary theory discuss the diffusion mechanism in detail. 08
Q.5 Discuss Molecular Beam Epitaxy technique with a neat sketch. 06
Discuss Chemical vapour deposition technique for the deposition of
Poly silicon films
08
Q.6 Write a note on buried layers 06
With a neat schematic, explain the DC magnetron sputtering technique 08
Q.7 Write a note on Electron beam Lithography 06
Write relevant diagrams, explain the masking sequence and process
flow for pnp and npn devices,