| 摘要 |
PURPOSE: A method for forming a trench isolation layer is provided to prevent a stacking fault due to facet without generating voids by performing an SEG(Selective Epitiaxial Growth) using a polysilicon layer remaining at the bottom of a trench. CONSTITUTION: After forming a pad oxide(11) on a semiconductor substrate(10), an etch stopping pattern(13) is formed on the pad oxide(11). A deep trench is formed by selectively etching the substrate(10) using the etch stopping pattern(13). A thermal oxide(15) grows at inner sidewalls of the trench by annealing. Then, a silicon nitride liner(17) is formed on the thermal oxide(15). A polysilicon layer and a silicon oxide are sequentially formed on the resultant structure. The silicon oxide formed on the etch stopping pattern(13) is selectively removed by CMP(Chemical Mechanical Polishing). The exposed polysilicon layer is removed by selectively etching, thereby remaining a polysilicon layer(311) formed at the bottom of the trench. Then, the silicon oxide formed in the trench is removed by isotropic etching. A silicon epitaxial layer selectively grows in the trench by SEG using the remained polysilicon layer(311) as a base or seed layer.
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