Heat removal by removal of buried oxide in isolation areas

Abstract

In one embodiment, the present invention relates to a method of forming a Silicon-on-Insulator substrate involving providing a structure comprising a bulk silicon layer, a buried insulation layer over the bulk silicon layer, a silicon device layer over the buried insulation layer, and a mask layer over the silicon device layer; etching portions of the mask layer, the silicon device layer, and the buried insulation layer thereby forming openings and exposing portions of the bulk silicon layer; depositing polysilicon in the openings; removing a portion of the polysilicon in the openings to form polysilicon sidewalls adjacent the silicon device layer and the buried insulation layer and to form gaps at least partially surrounded by the polysilicon sidewalls; depositing an insulation material in the gaps; and removing the mask layer. In another embodiment, the present invention relates to a Silicon-on-Insulator substrate made of a bulk silicon layer, a buried insulation layer over the bulk silicon layer, a silicon device layer over the buried insulation layer; a plurality of at least one of holes and trenches in the silicon device layer and the buried insulation layer, wherein the plurality of at least one of holes and trenches contains a polysilicon sidewall adjacent the bulk silicon layer, the buried insulation layer, and the silicon device layer, the polysilicon sidewall surrounding an insulating material, the insulating material in contact with the bulk silicon layer.

Dependencies are inferred from the claim text.