Silicon is exposed to a gas at 1473K that established a concentration of 1018 atoms /cm3 of Al on the surface. At this temperature D is 1.151015m2/s. a) After 30 minutes - at what depth below the surface will the concentration of Al be 1016 atoms /cm3 ? b) Calculate the amount of Al (atoms /cm2 ) that has diffused into the Si after 30 minutes. Silicon is exposed to a gas at 1473K that established a concentration of 1018 atoms /cm3 of Al on the surface. At this temperature D is 1.151015m2/s. a) After 30 minutes - at what depth below the surface will the concentration of Al be 1016 atoms /cm3 ? b) Calculate the amount of Al (atoms /cm2 ) that has diffused into the Si after 30 minutes