Question

Thin gate oxide in a CMOS process is preferably grown using
1. wet oxidation 
2. dry oxidation
3. epitaxial deposition
4. ion implantation

Answer 1

Correct Answer - Option 2 : dry oxidation

Explanation:

Dry oxidation is used to achieve high-quality oxide growth. Dry oxidation produces a very good quality of oxide that's why dry oxidation is preferred over wet oxidation to grow thin gate oxide in CMOS fabrication. Dry oxidation is used to form thin oxide films and give better electrical properties. It is slow compare to wet oxidation.  

The  Reaction involved is-

Si + O₂ → SiO₂

NOTE-

Wet oxidation proceeds at a faster rate and is used to form thick oxide films. This is because water vapor diffuses through SiO2 faster than oxygen. The  Reaction involved is-

Si + 2H_2­O → SiO₂ + H₂