Semiconductor device having trench isolation layer and method for manufacturing the same

摘要

A semiconductor device is formed by including the step of forming a polycrystalline silicon layer on a semiconductor substrate which includes a pad oxide. A trench is formed in the semiconductor substrate by etching sequentially a part of the polycrystalline silicon layer, a part of the pad oxide layer, and a part of the semiconductor substrate. An oxide layer spacer is formed on the walls of the trench and the side walls of the etched pad oxide layer and the etched polycrystalline silicon layer. A nitride liner is formed on the oxide layer spacer. The trench is filled with an insulating layer on the nitride liner and the insulating layer is planarized until the polycrystalline silicon layer is exposed. And then the polycrystalline silicon layer is dry-etched.