METHOD FOR MANUFACTURING OF MOS DEVICE WITH DUAL GATE STRUCTURE

摘要

A method for manufacturing an MOS device with a dual gate structure is provided to minimize contamination in a surface of a substrate by using a thick gate oxide layer as a passivation layer not to expose the substrate. A thin gate oxide layer is formed along the whole surface of the upper part of a substrate(100). A polysilicon layer is deposited in the whole surface of the upper part of the thin gate oxide layer. The substrate is classified into a low voltage region and a high voltage region. The thin gate oxide layer is formed in the low voltage region. The thick gate oxide layer is formed in the high voltage region. A native oxide layer of the low voltage region and the native oxide film of the high voltage region are formed at the same time. A photoresist pattern is formed in the high voltage region.