Question

Explain dry and wet oxidation processes in vlsi

Answer 1

In microfabrication, thermal oxidation is a way to produce a thin layer of oxide (usually silicon dioxide) on the surface of a wafer. The technique forces an oxidizing agent to diffuse into the wafer at high temperature and react with it. The rate of oxide growth is often predicted by the Deal-Grove model.[1] Thermal oxidation may be applied to different materials, but this article will only consider oxidation of silicon substrates to produce silicon dioxide.

Answer 2

Dry Oxidation

Dry oxidation has a lower growth rate than wet oxidation although the oxide film quality is better than the wet oxide film.

wet Oxidation

In case of wet oxidation where water is use instead of oxygen, the water molecule can dissociate at high temperatures to form hydroxide OH that can diffuse in the silicon faster than molecular O2. Therefore the wet oxidation process has a significantly higher oxidation rate than the dry oxidation.