Abstract: A process for treatment of a silicon wafer to achieve therein a controlled distribution of the density of oxygen precipitate nucleation centers. In the process, one face of the wafer is shielded and the other, unshielded, face of the wafer is exposed to an atmosphere which contains nitrogen or a nitrogen compound gas and which has an essential absence of oxygen during a rapid thermal treatment at a temperature of at least about 1175.degree. C. The process generates nucleation centers which serve as sites for the growth of oxygen precipitates during a subsequent heat treatment and which have a peak density proximate the unshielded face of the wafer.