Devices such as transistors are made by doping semiconductors with different dopants to generate regions that have p - or n-type semiconductivity. The diffusion coefficient of phosphorus (P) in Si is 6.51013cm2/s at a temperature of 1100C. Assume the source provides a surface concentration of 1030 atoms /cm3 and the diffusion time is one hour. Assume that the silicon wafer contains no P to begin with. Calculate the depth at which the concentration of P will be 1018 atoms /cm3