| 摘要 |
PURPOSE: A method for fabricating a semiconductor device is provided to improve a characteristic of junction leakage current and yield, by preventing the boron ions implanted for forming a source/drain region from transferring to an isolation layer. CONSTITUTION: A stack structure composed of a pad oxide layer and a nitride layer is formed on a semiconductor substrate(31). The stack structure and a predetermined thickness of the substrate are etched to form a nitride layer pattern(35), a pad oxide layer pattern(33) and a trench by using an isolation mask as an etch mask. The first buried insulation layer is formed on the resultant structure by a predetermined thickness. The first buried insulation layer is blank-etched to form a spacer(40) on the sidewall of the trench wherein the upper corner of the trench is exposed. Nitrogen ions are implanted into the exposed upper corner of the trench. The resultant structure is sacrificially oxidized to round the upper corner of the trench. The second buried insulation layer(41) is formed on the resultant structure. The second buried insulation layer is planarized to form an isolation layer filling the trench. The nitride layer pattern is eliminated.
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