| 摘要 |
PURPOSE: A method for forming an isolation layer is provided to be capable of preventing moat phenomenon generated at top edge portions of a trench. CONSTITUTION: A pad oxide layer and a silicon nitride layer are formed to expose an isolation region of a substrate(200). An insulating spacer(203) is formed at both sidewalls of the silicon nitride layer. After forming a trench(210), the first and second thermal oxide layer(212,214) are formed on the trench. After forming a diffusion barrier layer(216) on the second thermal oxide layer, an isolation layer(221) is filled into the trench. The silicon nitride layer, the pad oxide layer, the insulating spacer and the diffusion barrier layer are selectively removed to expose the substrate. The third thermal oxide layer(218) is formed on the exposed substrate.
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