| 摘要 |
A method for forming an isolation layer of a semiconductor device is provided to easily perform an ISO gap-fill process and stabilize distribution of ion implantation by oxidizing a trench top part after an ISO hard mask is etched. A pad oxide layer and a pad nitride layer are sequentially formed on a semiconductor substrate(100). The nitride layer and the pad oxide layer are partially removed to expose the semiconductor substrate wherein the depth of the exposed semiconductor substrate is 150~300 angstroms. An oxide layer is formed in the exposed semiconductor substrate to oxidize the top corner of a trench(110), having a thickness of 30~80 angstroms. The oxide layer and the semiconductor substrate are sequentially removed to form a trench. After a gap-fill process is performed, the nitride layer and the pad oxide layer are removed. A tunnel oxide layer(114) and polysilicon(116) for a floating gate are formed in a region from which the nitride layer and the pad oxide layer are removed.
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