Analysis of structural defects in silicon-on-insulator layers with x-ray reflection topography

Abstract

The advantageous use of X-ray reflection topography for evaluating the crystalline quality of silicon-on-insulator (SOI) wafers is demonstrated. SOI wafers consist of oxidized silicon wafers with a thin single crystal layer on top. Structural analyses to investigate the quality of the SOI layer were carried out on wafers in which the top layer was recrysrallized by a graphite strip-heater, combined with seeding from the (100)-oriented silicon substrate. Separate X-ray reflection topographs of the thin SOI film and of the underlying substrate could be made due to a slight misorientation between the layer and the substrate. The selective reflection of the X-rays makes it possible to reveal a much higher density of defects in the SOI layer than reported up to now.