Optimized conditions for the formation of buried insulating layers in Si by high dose implantation of oxygen

Abstract

Results are presented detailing the dependence of the residual damage on substrate temperature and dose for high dose implantation of oxygen in Si. It has been previously demonstrated that a buried oxide layer can be formed by this method. However, the usefulness of this silicon on insulator (SOI) structure has been limited by the considerable damage which accumulates in the crystal overlayer during irradiation. Much of the damage remains even after high temperature annealing. It is shown that the quality of the crystalline layer depends critically on the implant conditions. The preservation of the crystal quality of this layer by implanting at high temperatures to prevent defect clustering competes with the adverse effects caused by rapid diffusion of oxygen into this region. This leads to a rather narrow range of temperature over which optimization occurs. Rutherford backscattering/channeling spectroscopy and cross-sectional, transmission electron microscopy were used for analyzing the samples and for understanding the phenomena of formation of buried insulating layers.