In: Physics
An n-type silicon wafer undergoes a pre-deposition diffusion process with a constant surface concentration of boride gas; the resulting concentration of boron in silicon at the surface is estimated to be 1x1018 atoms cm-3. The background concentration of trace boron atoms in the silicon wafer is estimated to be 1x1014 cm-3. (A) Estimate the depth of the p-n junction below the surface when the background doping concentration of the n-type impurity is 3.45 x1016 cm-3; assume the diffusion process proceeds for 10 minutes and has a diffusion parameter given by 10-12 cm2 s -1. (B) Estimate the number of boron atoms (per cm^2) introduced in this thin surface layer following the pre-deposition step.