| 摘要 |
PURPOSE: A method of forming a gate oxide is to remove COP(crystal originated particles), oxygen precipitates or metallic impurities in an active region, thereby improving quality of the gate oxide. CONSTITUTION: A pad oxide and a nitride layer are deposited on a semiconductor substrate(10) in this order. A photoresist is coated thereon and prescribed portions of the pad oxide, the nitride layer and the substrate are etched to form a trench portion in the substrate. The trench portion is completely filled with a gap-fill oxide layer, followed by planarization using a CMP(chemical mechanical polishing) process. The nitride layer and the pad oxide are removed to form an isolation layer. A sacrificial oxide layer is then formed on the entire surface, followed by forming a well(70). Thereafter, the sacrificial oxide layer is removed and a hydrogen annealing is performed on the substrate forming a denuded zone(90) therein, followed by annealing it to form a gate oxide.
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