2. (40\%) In the fabrication of a p-type semiconductor, elemental boron is diffused a small distance into a solid crystalline silicon wafer. A physical vapor deposition process keeps the boron concentration at the wafer surface equal to 51020#P/cm3 Si. We desired to produce a thin film of silicon doped to a boron concentration of at least 3.31019#P/cm3Si at a depth of 0.3m from the surface of the wafer. It is desired to achieve this target within a 20 -minute process time. (a): (10\%) It is known that the temperature dependence of the diffusion coefficient of boron (A) in silicon (B) is given by DAB=D0exp(Q0/RT), where D0=0.02cm2/s, and Q0=2.74105J/mole. At what temperature should be operated ? CA,SCA,0CACA,0=1erf()=1erf(2DABtz) (b): (20%) Verify the flux of boron atoms at the wafer surface (z=0) is NA,z(t)=tDAB(CA,SCA,0) (c): (10%) What is the flux of boron atoms at the wafer surface at 20min