3. One step of the manufacturing of silicon solar cells is the molecular diffusion (doping) of elemental phosphorous (P) into crystalline silicon to make an n-type semiconductor. This P-doped layer needs to be at least 0.5m into the 250m thick wafer. The maximum solubility of phosphorous within crystalline silicon is 5.01020P atoms /cm3 at the 1050C temperature of this process. Initially, there is no phosphorous impurity in the crystalline silicon. Calculate how long in minutes it will take to reach a concentration of P atoms of 1.21020cm3 at a depth of 0.5m