Nature of Lattice Defects Induced by Excimer Laser Irradiation for Extrinsic Gettering

Structure and thermal behavior of lattice defects in silicon induced by excimer laser irradiation, which is expected to be adopted as a new extrinsic gettering technique, were examined by transmission electron microscopy. Stacking fault tetrahedra and a peculiar type of dislocations which appeared in a V-shape were found in a melted and regrown layer of an as-irradiated sample. After subsequent heat treatment, slip dislocations were generated from the traces of laser beam shot and the stacking fault tetrahedra were mostly transformed into the V-shaped dislocations. These V-shaped dislocations were proved to be thermally stable and were expected to work as effective extrinsic gettering centers.