| 摘要 |
PURPOSE: A semiconductor device having a shallow trench isolation and a fabricating method thereof are provided to enhance isolating function but to maintain a shallow depth of the trench isolation. CONSTITUTION: A semiconductor device includes a shallow trench isolation and a LOCOS oxide layer(26) formed to the bottom of the trench. In a fabrication process, a pad oxide layer(12) and a silicon nitride layer(14) are formed on a substrate(10). Then, the both layers(12,14) and the substrate(10) are partly etched through a photoresist mask, so that the trench is formed. After the photoresist mask is removed, a second silicon nitride layer and a polysilicon layer are formed on overall surfaces. Subsequently, insulating spacers(24) composed of both the second silicon nitride layer and the polysilicon layer are formed on sidewalls of the trench by an etch-back process. Next, the LOCOS oxide layer(26) is formed to the bottom of the trench, and a USG layer(28) is then formed in the trench.
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