Question 7: A 2mm thick silicon wafer is to be doped with Sb in order to create a p-type region. This is done by passing a SbCl3/H2 gas mixture over the surface of the wafer at 1200C which fixes the Sb concentration at 10²³ atoms/m. It is desired to have a donor density(i.e. Sb concentration) that is greater than or equal to 3x10²² atoms/m over a depth of 1m below the surface. Determine the exposure time to achieve this. [Do = 1.3x10m/s; Q=383 KJ/mole]