Patent ID: 7745902

Claim:
An isolation trench for use in a semiconductor device comprising: a substrate of said semiconductor device; a trench etched in said substrate; a silicon dioxide liner comprising a first portion in said trench and a second portion over horizontal portions of the substrate that are adjacent to the trench, wherein the second portion of the silicon dioxide liner comprises a first top and a first side, the first side extending from the first top to the substrate; polysilicon material comprising a first portion filling said trench and a second portion over said filled trench and extending laterally over at least one edge of the trench to protect said silicon dioxide liner, wherein the second portion of the polysilicon material comprises a second top and a second side, the second top comprising a notch, the second side extending from the second top to one of: the silicon dioxide liner and the substrate, wherein the second portion of the polysilicon material completely covers the first top of the second portion of the silicon dioxide layer; and a layer of oxidation material formed over the second portion of the polysilicon material, wherein the layer of oxidation material contacts the second top and the second side of the second portion of the polysilicon material and fills the notch in the second top of the second portion of the polysilicon material.