A new optical method for identifying crystal defects in silicon-on-insulator materials

An optical method for rapid assessment of SOI structures is developed. This method is based upon angle lapping and etching to observe crystal defects in SOI structures. Traditional beveling methods introduce defects due to mechanical damage resulting from unintentional scratches caused by the material breaking loose from the sides of the sample. The proposed approach covers the sidewalls and the surface of the sample during lapping with a waxy material which provides a thick soft matrix to embed loose particles and eliminate the scratches. The method has been used to investigate both SIMOX and ISE structures. The proposed method has a greater sensitivity of defect detection than the cross-sectional transmission electron microscopy commonly used in defect studies and it is also well suited for evaluating process induced defects in bulk silicon devices