Undesired contamination of silicon surface in IC Fabrication process is prevented by ?

Undesired contamination of silicon surface in IC Fabrication process is prevented by ?

a) Diffusion
b) Epitaxy
c) Oxidation
d) Passivation

Correct Answer : d) Passivation

Explanation :

Passivation is the only process that can eliminate impurity level of silicon surface which is a part of oxidation process but not a obligatory step of oxidation despite of diffusion and epitaxy.