Reduction of Grown‐In Defects by High Temperature Annealing

Abstract

This research investigated the mechanism for the reduction of grown‐in defects in Czochralski silicon wafers by high‐temperature annealing for various annealing temperatures and ambients. Annealing at 1300°C in an argon ambient could eliminate not only surface grown‐in defects crystal originated particles (COPs), but also bulk grown‐in defects at 100 μm depth from the surface. Annealing at 1200 and 1250°C in an argon ambient also eliminated COPs, but their effects on bulk grown‐in defects were limited to shallower regions from the surface with lower annealing temperatures. On the other hand, annealing in an oxygen ambient could not reduce grown‐in defects even at 1300°C. It is thought that removal of oxide films on the inner walls of grown‐in defects is the first step in the reduction process of the grown‐in defects. Oxygen annealing cannot remove the oxide film, but rather enlarges them, and the grown‐in defects remain. Argon annealing can remove the oxide films, and subsequent absorption of silicon self‐interstitials reduces the grown‐in defects. © 2000 The Electrochemical Society. All rights reserved.