Patent ID: 8440553

Claim:
A method of producing a vertically inhomogeneous platinum or gold distribution in a semiconductor substrate with a first and a second surface opposite the first surface, the method comprising: diffusing platinum or gold into the semiconductor substrate from one of the first and second surfaces of the semiconductor substrate, wherein diffusing platinum or gold in the semiconductor substrate is performed such that the semiconductor substrate comprises a platinum—or gold maximum concentration of 5×10 14 cm −3 ; removing platinum—or gold—comprising residues remaining on the one of the first and second surfaces after diffusing the platinum or gold; forming a phosphorus—or boron-doped surface barrier layer on the first or second surfaces, wherein the phosphorus—or boron-doped surface barrier layer comprises a maximum concentration of at least 5×10 18 cm −3 ; and after removing the platinum- or gold-comprising residues, heating the semiconductor substrate for local gettering of the platinum or gold by the phosphorus- or boron-doped surface barrier layer, wherein the heating is performed at a temperature between 450° C. and 850° C., such that a vertically inhomogeneous depletion of the diffused platinum or gold is formed by local gettering, and the vertically inhomogeneous platinum or gold distribution results in the semiconductor substrate.