Indium atoms are to be diffused into a silicon wafer using both pre-deposition and drive-in heat treatments; the background concentration of In in this silicon material is known to be 2 ( 1020 atoms/m3. The drive-in diffusion treatment is to be carried out at 1175(C for a period of 2.0 h, which gives a junction depth xj of 2.35 (m. Compute the pre-deposition diffusion time at 925(C if the surface concentration is maintained at a constant level of 2.5 ( 1026 atoms/m3. For the diffusion of In in Si, values of Qd and D0 are 3.63 eV/atom and 7.85 ( 10(5 m2/s, respectively?