Methods for gettering in semiconductor substrate

摘要

A method for forming gettering sites and gettering impurities in a substrate layer includes producing a first masking layer over the substrate layer and patterning the masking layer to define openings at locations where trenches will be formed in the substrate layer at a later time. Ions are then implanted into the substrate layer to produce gettering sites. The gettering sites are disposed at a depth in the substrate layer such that the sites are removed when the trenches are formed. The first masking layer is removed and impurities driven to the gettering sites by thermally processing the substrate layer. A second masking layer is then produced over the substrate layer and patterned to define openings at locations where the trenches will be formed. The substrate layer is etched to produce the trenches. The gettering sites and gettered impurities are removed when the trenches are etched into the substrate layer.