THIN BURIED OXIDE IN OXYGEN-IMPLANTED SILICON

SiO2 precipitation in oxygen-supersaturated silicon was studied. Oxygen was inserted by ion implantation into single-crystal silicon. Evidence is given for a special phenomenon of oxygen blocking due to hot clouds resulting from collisional cascades. In the region where blocking is active, precipitates are formed in as-implanted conditions. A model is formulated and specialized to predict the dependence on depth of precipitate density and size. The existence of a buried region of precipitates is useful for producing a thin buried oxide. The Low-Dose SIMOX (LODOX) structure obtained provides a solution for many problems that are typical of silicon substrates for CMOS applications.