Method of making photodetectors using ion implantation and laser annealing

摘要

A semiconductor substrate is bombarded by ions of sufficient energy to penetrate the surface of the substrate to some average predetermined depth. The substrate is then scanned by a laser beam having a small diameter compared to the substrate thickness and having sufficient energy to heat the substrate to the predetermined depth. The heat allows surface damage on the substrate from the ion bombardment to heal, and allows the ions and substrate to form a compound to the predetermined depth with controllable redistribution. This compound is the photodetector of the method. The ions may be implanted through a mask to produce isolated detector regions, or the entire substrate surface may be bombarded, and those regions not desired for detector regions may be removed by a laser beam of sufficient energy to cause evaporation of a layer of the substrate. Exemplary substrate and ions are respectively cadmium telluride and mercury.