Semiconductor devices and methods of forming a trench in a semiconductor device

摘要

Semiconductor devices and methods to form a trench in a semiconductor device are disclosed. A disclosed process comprises: forming a hollow by etching a portion of a semiconductor substrate; forming a side wall layer in an inner side wall of the hollow; forming a trench by further etching the semiconductor substrate exposed through the bottom of the hollow; and filling the trench by forming an insulation film on the side wall layer and the trench.