| 摘要 |
A method for manufacturing an isolation layer in a semiconductor device is provided to obtain effectively a round portion from a trench top corner and to remove moat by oxidizing a polysilicon layer on a pad oxide layer using a trench lateral oxidation. A pad oxide layer(22a), a polysilicon layer and a nitride layer are sequentially formed on a semiconductor substrate(21a). The substrate is partially exposed to the outside by etching selectively the nitride layer, the polysilicon layer and the pad oxide layer. A trench is formed by etching the exposed substrate. A lateral oxidation is performed on the resultant structure to grow a sidewall oxide layer(27) along an inner surface of the trench. At this time, the polysilicon layer is oxidized. A buried insulating layer(28a) is then formed on the resultant structure.
|
