VLSI Technology (utu previous year question paper)

utu previous year question paper

sub:- VLSI Technology 

b.tech sem 5th

Uttarakhand Technical University

Q1:- Attempt any four parts:

1. Describe CZ process in detail with neat diagram. What is the pull Rate in CZ technique? How the Pull rate is controlled during the CZ crystal growth process?
2. A silicon ingot with 0.5 * 10^16 boron atoms/cm^3 is to be grown by CZ method. What should be the concentration of boron in the melt to obtain the required doping concentration? The segregation coefficient of the boron is 0.8
3. Describe the effect of orientation on oxidation? Prove that linear growth rate occur for short time oxidation.
4. Calculate the oxidation time required for the thermal oxidation of 100A thickness at 1000 degree C. NOTE: B= 5.2  105A 2/min. and B/A = 111A/min {A = angstrom }
5. Describe two most common methods used for measuring thermal oxide thickness.