| 摘要 |
<p>The invention is intended to form a thin tunnel oxide film and a thick gate oxide film simultaneously on the silicon substrate surface, by making use of the difference in the rate of oxidation between the surface of nitrogen ion injection region and the surface of injection-free region of the silicon substrate. For this purpose, nitrogen ions are injected into the area for forming the tunnel region in the silicon substrate surface, and then oxidizing the silicon substarte. Accordingly, the stress in the boundary portion between the tunnel oxide film and gate oxide film is greatly alleviated, and the number of times for rewriting data may be greately enhanced.</p> |
