One 725 micron thick Si wafer was originally doped with phosphorus only. The phosphorus number concentration was uniform and Cpno= 1e15 cm^(-3). Then, another 20 nm thin Si layer was deposited and the doping of this 20 nm layer was done during the deposition with uniform phosphorus doping level of 1e18 cm^(-3). This technique is called in-situ doping. The deposition temperature was low enough that we can consider that the phosphorus diffusion is negligible during this step. a) What is the phosphorus dose Qn introduced in the deposition step? b) Please plot the phosphorus profile before and after the deposition step in a linear scale. Please use a coordination system such that x = 0 at the original Si wafer surface, and going into the wafer is the positive x direction. Then, a layer of Si dioxide was deposited to prevent the dopants from evaporation. The oxide deposition temperature was low enough such that the diffusion in this step can be ignored. After that, the wafer went through a drive-in step. The drive-in condition was 4 hours at 1000C. Assume that the phosphorus diffusivity is the intrinsic diffusivity with data provided in the table below. c) What is the diffusion length / of the drive-in step? d) We assume that /> 100 nm is the condition that the doping in the 20 nm layer can be viewed as a delta function for the drive-in diffusion step. Please determine whether it is appropriate to use the half Gaussian distribution as the final profile. e) Please plot the phosphorus profile after the drive-in step on the same plot in b). You can use a plotting tool for that and do that after the class. f) What are the phosphorus number concentrations at x = 50, 300 and 600 nm respectively?