Patent ID: 7749869
Filing Date: 2010-07-06
Classification: H01L

Abstract:
1. A method for improving the minority carrier lifetime of a scrapped semiconductor wafer having contaminants including metallics therein comprising: selecting a scrapped semiconductor wafer having a bare upper surface and a bare lower surface, said scrapped semiconductor wafer comprises a previously processed semiconductor wafer that is now void of any doped region and any semiconductor device; and annealing said scrapped semiconductor wafer at a temperature in the range from about 1200° C. to about 1375° C. in a gaseous ambient of oxygen, an inert gas and a chlorine containing gas for a time period from about 1 minute to about 50 hrs whereby said contaminants form volatile metal chlorides and evaporate from the wafer and wherein SiOx precipitates and gettering sites within the scrapped semiconductor wafer are removed during said annealing to enhance minority carrier lifetime within the scrapped semiconductor wafer.