Patent ID: 7670895

Claim:
A process of forming an electronic device comprising: providing a workpiece including a substrate, an insulating layer, and a semiconductor layer, wherein the insulating layer lies between the substrate and the semiconductor layer; patterning the semiconductor layer to define an opening extending to an insulating layer, wherein after patterning the semiconductor layer: the opening has a bottom, wherein the insulating layer lies along the bottom of the opening; the semiconductor layer has a sidewall and a surface; the surface is spaced apart from the insulating layer; and the sidewall extends from the surface towards the insulating layer; forming a first layer over the substrate, wherein the first layer substantially fills the opening within the semiconductor layer; removing a part of the first layer from within the opening, wherein after removing the part of the first layer: a remaining portion of the first layer lies within the opening and adjacent to the sidewall and lies along substantially all of the bottom of the trench; the remaining portion of the first layer is spaced apart from the surface; the remaining portion of the first layer has a first thickness at a center of the opening and a second thickness at a point closest to the sidewall, wherein as measured from the bottom of the opening, the first thickness is at least as thick as the second thickness: the remaining portion of the first layer fills approximately 20% to approximately 50% of the opening: and a portion of the sidewall is exposed within the opening; oxidizing the semiconductor layer while the remaining portion of the first layer lies within the opening, wherein: a first corner of the semiconductor layer immediately adjacent to the surface becomes rounded during oxidizing the semiconductor layer; a second corner of the semiconductor layer at an interface between the semiconductor layer and the insulating layer substantially maintains its shape during oxidizing the semiconductor layer; and the portion of the sidewall of the semiconductor layer is oxidized; depositing an insulating layer that substantially completely fills a rest of the opening after oxidizing the semiconductor layer; and removing a portion of the insulating layer lying outside the opening to form a field isolation region.