Patent ID: 8343862

Claim:
A process of producing a field stop zone within a semiconductor substrate having semiconductor elements formed at a top main surface thereof, implanting dopant atoms into a bottom main surface of the substrate to form a field stop zone between a channel region and the bottom main surface of the substrate, at least some of the dopant atoms having energy levels of at least 0.15 eV below the energy level of the conduction band edge of semiconductor substrate; wherein implanting dopant atoms includes implanting other dopant atoms, which act as shallow impurities, in a further implantation zone, including selecting a dopant dose ratio between dopant atoms having an energy level that is at least 0.15 eV below the energy level of the conduction band edge and other dopant atoms which act as shallow impurities, to obtain an approximately temperature-independent softness during turn-off across the operating temperature range of a semiconductor device formed within said semiconductor substrate; and laser annealing said field stop zone.