In the fabrication of a p-type semiconductor, elemental boron is diffused a small distance into a solid crystalline silicon wafer. The boron concentration within the solid silicon determines semiconducting properties of the material. A physical vapor deposition process keeps the concentration of elemental boron at the surface of the wafer equal to 51020cm3siliconatomsboron. In the manufacture of a transistor, it is desired to produce a thin film of silicon doped to a boron concentration of at least 1.71019cm3siliconatomsboron at a depth of 0.20 microns from the surface of the silicon wafer. It is desired to achieve this target within a 30-min processing time. The density of solid silicon can be stated as 51022cm3siliconatomssilicon. What reasonable assumptions can be made? Provide a simplified version of the conservation equation based on these assumptions