A: Assume that Aluminum is evaporating from a source at the rate of 5 X 10^20 atoms/sec. Make an estimate of the time it would take to form a 2000 layer on a 4 wafer that is 150mm distant [and perfectly square to the source] B: If the evaporating source used above is charged with 5 grams of Aluminum How long could it evaporate at that rate?