| 摘要 |
A method for fabricating a trench isolation layer in a semiconductor device is provided to prevent loss of a buried oxide layer by forming a protective layer on a surface of the buried oxide layer. A pad oxide layer(22) and a pad nitride layer(23) are sequentially formed on a silicon substrate(21) where an active region and an isolation region are defined. The pad nitride layer, the pad oxide layer, the silicon substrate in the isolation region are sequentially etched to form a trench(24) on the silicon substrate with a predetermined depth. A buried oxide layer(26) is deposited on the whole surface to gap-fill an inside of the trench. The buried oxide layer is etched up to a height of the silicon substrate. A protective layer(27) is deposited on the whole surface along the surface of the buried oxide layer and the surface of the pad nitride layer. A temporary protective layer(28) is formed on the protective layer in the isolation region. The temporary protective layer and the protective layer are planarized up to the surface of the pad nitride layer. The pad nitride layer is eliminated.
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