When silicon is oxidized, some silicon is consumed from the surface to form silicon dioxide. The Pilling-Bedworth (P-B) ratio is the ratio of SiO2 volume grown to Si volume consumed. Required:
a. Derive an equation for calculating the P-B ratio in terms of Si and SiO2 molecular weights and densities.
b. Draw to scale cross-sections of a silicon wafer before and after growing 1000A of SiO2. Align the drawings using the original Si surface as a reference. Label the diagram completely, including the original surface, the oxide surface, and the Si-SiO2 interface.