One integrated circuit design calls for the diffusion of arsenic into silicon wafers; the background concentration of As in Si is 2.5  1020 atoms/m3. The predeposition heat treatment is to be conducted at 1000°C for 45 minutes, with a constant surface concentration of 8  1026 As atoms/m3. At a drive-in treatment temperature of 1100°C, determine the diffusion time required for a junction depth of 1.2 m. For this system, values of Qd and D0 are 4.10 eV and 2.29  10-3m2/s, respectively. about 13,900 s, which corresponds to td =3.86 h