Semiconductor devices and methods of forming the same

摘要

Methods of forming a semiconductor device include forming a structure including an oxide layer, a polysilicon layer and a mask layer on a substrate. The structure is etched to form an opening therein and the substrate beneath the opening to form a trench. An insulating structure is formed in the opening and the trench. The mask is removed and a second polysilicon layer is formed adjacent the second insulating structure. Sidewall portions of the second insulating structure are removed prior to formation of the second polysilicon layer. The thickness of the first polysilicon layer may be chosen based on the desired thickness of the second polysilicon layer. Resulting devices are also disclosed.