| 摘要 |
PURPOSE:To prevent an insulating layer, positioned on the shoulder of a groove provided vertically in an Si substrate, from growing thin and thereby to prevent its voltage-withstanding capability from degradation by a method wherein the insulating layer on the groove shoulder is formed selectively. CONSTITUTION:An oxide film 6 and then a nitride film 8 is formed on an Si substrate 1. A window is provided through the nitride film 8 and is subjected to oxidation for the formation of an SiO2 layer 7. A process follows wherein the SiO2 layer 7 and the Si substrate 1 are subjected to etching, when the nitride film 8 serves as a mask, for the provision of a vertical groove 2. Finally, the nitride film 8 is removed and another SiO2 layer 3 is formed, as the result of which the SiO2 layer may be thicker on the shoulder 5 of the groove 2 than on other portions, which contributes to the improvement of the device voltage- withstanding capability. |
