| 摘要 |
PURPOSE:To reduce bird beaks and bird heads by applying a scratch by implanting high density ions to a region to be selectively oxidized and oxidizing at low temperature, thereby utilizing accelerating oxidation phenomenon. CONSTITUTION:A silicon oxide film 2 and a silicon nitride film 3 are sequentially formed on a silicon substrate 1, a hole 4 is formed at the film 3, and ions are implanted. The impurity 9 to be implanted is optimally argon of inert gas in the substrate 1 by applying scratch to the substrate 1 efficiently. Higher ion implanting density is effective. High pressure oxidation in steam is performed at low temperature of 900 deg.C or lower to obtain a separate oxide film 10. If performed at high temperature of 900 deg.C or higher, the scratch is annealed during the oxidation to reduce the accelerating oxidation effect. The suppressing effect of bird beak or bird head is remarkably exhibited at lower temperature of approx. 800 deg.C. |
