| 摘要 |
PURPOSE: A formation method of an isolating layer of semiconductor device is provided to improve a characteristic and a reliance by depositing an alumina layer using a CVD(Chemical Vapor Deposition) before filling a burying oxide into a trench-etched portion. CONSTITUTION: By etching to a defined depth of a substrate(100) having a pad oxide(110) and a pad nitride(120), trenches are formed on the substrate(100). After removing a sacrificial oxide formed by a sacrificial oxidation of the exposed silicon of the trenches at the temperature of 700 - 1100 deg.C, a thermal oxide(140) is formed. Then, a diffusion barrier(150) made of an Al2O3 is deposited on the resultant structure by a CVD(Chemical Vapor Deposition), thereby preventing a volume swelling of the silicon surface due to a following thermal treatment. Then, an oxide(160) is enough deposited to fill up the trenches.
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