M.Sc. (Semester III) (CBCS) Examination Nov/Dec-2018
Materials Science
MATERIALS PROCESSING
Time: 2½ Hours Max. Marks: 70
Instructions: All questions are compulsory.
All questions carry equal marks.
Q.1 Multiple choice questions. 14
The atmospheric pressure is equal to
760 Torr 1 Torr
7.6 Torr 76 Torr
In resistive evaporation the filaments are usually made of refractory metals
such as Tungsten or Tantalum mainly because of their
Melting point Conductivity
Ductility Hardness
DC sputtering cannot be used for deposition of
Metal Alloy
Oxide All above
In physisorption due to adsorption of the adsorbate molecules the electronic
structure of the surface atoms
Changes irrespective of the adsorbate concentration
Does not change irrespective of the adsorbate concentration
Changes with respect to the adsorbate concentration
None of the above
The capillary nucleation theory considers the
Interface energy of the film and substrate
Roughness of the Substrate
Melting point of the substrate
All of the above
The sticking coefficient depends on
Substrate temperature Substrate area
Substrate shape None of the above
The important condition for electrodeposition is substrate.
Conducting Extremely flat
Rough Specific shaped
What are the main parameters affecting the nucleation process
Substrate charge Substrate roughness
Substrate shape Deposition rate
What is sputtering yield?
The number of sputtered atoms per unit solid angle
The number of sputtered atoms per second
The number of sputtered atoms per incident particle
The amount of energy which is dissipated after the collision with target (per
particle)
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10) For which conditions will a thin film have larger grains?
High deposition rate and high substrate temperature
High deposition rate and low substrate temperature
Low deposition rate and high substrate temperature
Low deposition rate and low substrate temperature
11) Which type of thin film growth can be expected in case when there is no
wetting between the deposited material and the substrate?
Only "island" type, no "layer"
Only "layer" type, no "island"
Both "island" and "layer" are possible
No deposition
12) In sputter-deposition of alloys, the composition of the deposited thin films___.
is same as that of the target composition
is not same as that of the target composition
depends on the plasma
depends on sputtering rate
13) In thermal evaporation the evaporation rate depends on
Pressure in the evaporation chamber
Size of the chamber
Shape of the chamber
Distance between the source and substrate
14) By changing the thin film deposition technique, which of the following property
of the thin film will not change?
Thickness Purity
Uniformity Temperature
Q.2 Answer the following. (Any Four) 08
Why chemisorption is stronger than physisorption?
Why ion pump is noise free?
Which principle is used to measure thickness of the film by quartz crystal
microbalance?
Why in case of MOCVD we get carbon impurity?
Why resistivity of the thin film increases with decrease in thickness?
Why there is a stress in thin films when there is mismatch between
thermal expansion coefficients of substrate and deposited material?
Write note on. (Any Two) 06
Ion plating
Spray pyrolysis
Diffusion pump
Q.3 Answer the following. (Any Two) 08
What are different advantages and disadvantages of CVD over PVD?
Explain working of pirani guage, in which vacuum range it can be used?
Discuss importance of ALD.
Answer the following. (Any One) 06
Write the principle of diffusion and turbo molecular pump.
Explain in detail different types of sputtering.
Q.4 Answer the following. (Any Two) 10
Discuss in brief different type of CVD.
Explain grain boundary and thin film diffusion.
Discuss thermal evaporation technique.
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Answer the following. (Any One) 04
How stress is generated in thin films?
Explain quartz crystal film thickness measurement.
Q.5 Answer the following. (Any Two) 14
Discuss different types of physical vapour deposition techniques.
Discuss mechanical, electrical and optical properties of thin films.
Discuss dc, magnetron and rf sputtering.