| 摘要 |
PURPOSE: A method for forming a field oxide layer is provided to prevent a deterioration of a gate oxide layer at peripheries of an active region. CONSTITUTION: In a formation of a field oxide layer, first a nitride oxide(31a) is formed on a silicon substrate(30) by nitrification of a pad oxide. Next, a nitride layer(32) to be used as an oxidation-resistant film is deposited on the nitride oxide(31a), and then selectively etched by a photomasking technology. However, a field region is still covered with a remainder of the nitride layer(32). Next, after an oxide layer is deposited on overall exposed surfaces, an oxide spacer is formed by dry-etch of the oxide layer, and the remainder of the nitride layer(32) and the nitride oxide(31a) on the field region are removed by a selective etch using the oxide spacer as a mask. Next, the oxide spacer is removed and consequently a nitride spacer(32a) is obtained at peripheries of the field region. A field oxide layer(35) is then grown.
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