gas mixture of antimony chloride and other gases

Consider a 2-mm-thick silicon (Si) wafer tobe doped using antimony (Sb). Assume thatthe dopant source (gas mixture of antimonychloride and other gases) provides aconstant concentration of 1022 atoms m3.We need a dopant profile such that the concentrationof Sb at a depth of 1 micrometeris 5 * 1021 atoms m3. What is the requiredtime for the diffusion heat treatment?Assume that the silicon wafer initially containsno impurities or dopants. Assume thatthe activation energy for diffusion of Sbin silicon is 380 kJ mole and D0 for Sbdiffusion in Si is 1.3 * 10-3 m2 s. AssumeT  1250°C.