Method for semiconductor device isolation using oxygen and nitrogen ion implantations to reduce lateral encroachment

摘要

The invention is a method to form a localized oxide isolation region by implantation of oxygen and nitrogen ions prior to a thermal oxide growth. In accordance with one embodiment of the invention, a silicon substrate is selectively masked with silicon nitride and oxygen ions are implanted into the unmasked regions of the substrate at an energy necessary to form a buried oxygen rich layer close to the substrate surface. The nitrogen ions are implanted at an angle such that they underlie the masked regions adjacent to the unmasked regions. The substrate is then oxidized to form silicon oxide using the silicon nitride as an oxidation mask.