PROCESS FOR THE PREPARATION OF AN IDEAL OXYGEN PRECIPITATING SILICON WAFER CAPABLE OF FORMING AN ENHANCED DENUDED ZONE

摘要

A process for heat-treating a single crystal silicon wafer to influence the precipitation behavior of oxygen in the wafer in a subsequent thermal processing step is disclosed. The wafer has a front surface, a back surface, and a central plane between the front and back surfaces. In the process, the wafer is subjected to a heat-treatment to form crystal lattice vacancies, the vacancies being formed in the bulk of the silicon. The heat-treated wafer is then oxidized by heating in the presence of an oxygen-containing atmosphere in order to establish a vacancy concentration profile within the wafer. The oxidized wafer is then cooled from the temperature of said oxidizing heat treatment at a rate which allows some, but not all, of the crystal lattice vacancies to diffuse to the front surface to produce a wafer having a vacancy concentration profile in which the peak density is at or near the central plane with the concentration generally decreasing in the direction of the front surface of the wafer.