Integrated circuit with trenches and an oxygen barrier layer

Abstract

A trench which has walls intersecting a surface of a semiconductor substrate and an oxidation/diffusion barrier layer lining the walls is disclosed. The oxidation/diffusion barrier extends over the edges of the trench to prevent, for example, stress defects in the trench corners and vertical bird's beak formation within the trench. A filler material such as polysilicon is deposited within the trench followed by the deposition of a planarizing layer over the trench. After heat is applied, the planarizing layer flows to form a planarized layer over the trench. Using high pressure and phosphosilicate glass for the planarizing layer, the planarizing layer flows appropriately at low temperatures for short times.