Abstract: A silicon substrate having a controlled oxygen content is sliced to form a wafer. The backside surface of the wafer is mechanically damaged for external gettering, polished, and subjected to heat for annealing to reduce strain and defects near the surface. The surface is then etched and the epitaxial layer formed by first growing an epitaxial layer, removing a substantial portion thereof, and then regrowing the layer to the required thickness. Immediately prior to device processing, an oxide layer is formed by heating the wafer, removing a portion of the epitaxial layer, and placing the wafer in an oxygen atmosphere. After a preselected time period in the oxygen atmosphere, the temperature is gradually reduced.