utu previous year question paper
sub:- VLSI Technology
b.tech sem 5th
Uttarakhand Technical University
Q1:- Attempt any four parts:
- 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?
- 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
- Describe the effect of orientation on oxidation? Prove that linear growth rate occur for short time oxidation.
- 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 }
- Describe two most common methods used for measuring thermal oxide thickness.