A Study of Defect Formation Mechanism at Edges of Local Oxidation of Silicon Structure

Abstract
We have investigated the effect of the oxygen concentration of the substrate upon defect formation at edges of the local oxidation of silicon (LOCOS) structure by preparing various kinds of substrate. It was found that the defect density was not correlated with oxygen concentration near the LOCOS-fabricated region and that no LOCOS defect was found when bulk defects were induced. The most probable model for the defect formation is proposed to be the combination of maximized tensile stress at LOCOS edges and agglomeration of ejected self-interstitials due to this stress, which is greatly affected by the existence of other strong sink sites such as bulk defects.