| 摘要 |
PURPOSE: A method for forming a trench type isolation layer of a semiconductor device is provided to restrain moat at edge portions of trench by depositing a liner nitride layer using PECVD(Plasma Enhanced CVD). CONSTITUTION: A trench mask pattern including a pad oxide and nitride layer(21,22) is formed on a silicon substrate(20). A trench is then formed. A sidewall oxide layer(23) is formed at inner walls of the trench by thermal oxidation processing. By selectively etching the sidewall oxide layer, an under-cut region is formed at the edge portion of the pad nitride layer(22). A liner nitride layer(24) is deposited by PECVD without depositing at the under-cut region. Then, an isolation layer is formed by filling an insulating layer in the trench and planarizing.
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