A silicon wafer, doped $p-$type, is initially coated with a $0\mathrm{.}35m$ thick oxide across the entire wafer. Two openings are made in the oxide following a photolithography and etching step. The exposed silicon below the two openings is next doped $n-$type. Lastly, a $0\mathrm{.}25m$ thick oxide is grown on the bare parts of the wafer.

a$.$ If the oxide was grown using dry $O_2$ at $1100C,$ how long would it take to grow the oxide over the bare parts of the wafer? Deal$-$Grove parameters are on Canvas in the file called 'SiOxidationDealGrove.pdf$\text{'}$

b$.$ If $640$ torr of wet $O_2$ was used at $1100C,$ how long would it take to grow the oxide over the bare parts of the wafer?

c$.$ Thinking about the regions of the wafer still covered by $0\mathrm{.}35m$ thick oxide, what would the total oxide thickness be following an oxidation process using dry $O_2$ at $1200C$ for $6\mathrm{.}0$ hrs$?$