Method of making trench isolation structures with oxidized silicon regions

Abstract

A trench isolation structure in a semiconductor substrate includes a trench opening in the surface of the substrate and a seamless oxide layer filling the trench. The seamless oxide layer is formed by forming a first oxide layer in the trench, adding a silicon material overlying the first oxide layer and within a gap on the first oxide layer between the trench sidewalls that tend to be produced in the preceding step, and oxidizing the silicon material to form a second oxide layer. The deposited silicon material expands during oxidation, filling the trench opening to produce a seamless oxide fill of the trench. This seamless trench isolation structure prevents accumulation of materials that reduce the yield of the finished semiconductor product.

Dependencies are inferred from the claim text.