| 摘要 |
A method for forming a trench bottom oxide layer in a semiconductor device is provided to selectively form a trench bottom oxide layer only on the bottom of a trench, by sequentially forming in a sidewall oxide layer and a nitride layer on a substrate including a trench, by etching the nitride layer to expose the bottom of the trench and by wet-oxidizing a part of the sidewall oxide layer exposed by the residual nitride layer. A sidewall oxide layer and a nitride layer are sequentially formed on a semiconductor substrate(100) including a trench(101). After a part of the nitride layer corresponding to the bottom of the trench is etched, a post-cleaning process is performed. A part of the sidewall oxide layer exposed by the residual nitride layer is oxidized by a wet process to form a trench bottom oxide layer(105) having a predetermined thickness. The nitride layer and the sidewall oxide layer which remains on the upper surface of the semiconductor substrate including the sidewall of the trench are eliminated.
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