LOCOS isolation for fully-depleted SOI devices

摘要

The present invention discloses a method including: providing a substrate; forming a buried oxide layer over the substrate; forming a thin silicon body layer over the buried oxide layer, the thin silicon body layer having a thickness of 3-40 nanometers; forming a pad oxide layer over the thin silicon body layer; forming a silicon nitride layer over the pad oxide layer; forming a photoresist over the silicon nitride layer; forming an opening in the photoresist; removing the silicon nitride layer in the opening; partially or completely removing the pad oxide layer in the opening; removing the photoresist over the silicon nitride layer; forming a field oxide layer from the thin silicon body layer in the opening; removing the silicon nitride layer over the pad oxide layer; and removing the pad oxide layer over the thin silicon body layer.;The present invention also discloses a structure including: a substrate; a buried oxide layer located over the substrate; a thin silicon body layer located over the buried oxide layer, the thin silicon body layer including active areas separated by isolation regions, the isolation regions having a modified bird's beak length that is 30-60% of a thickness of the thin silicon body layer; and a fully-depleted device located in each of the active regions.