| 摘要 |
PURPOSE:To make the thickness of an insulating film uniform, to prevent the concentration of an electric field and to improve a withstanding voltage characteristic, by forming round parts at the upper and lower end parts of a groove, which is provided in a substrate, in the structure of a groove shaped MOS capacitor. CONSTITUTION:A first SiO2 film 21 and an Si3N4 film 23 are formed on a silicon substrate 20. A groove 25 reaching the substrate 20 is formed. Then, a second SiO2 film 26 is formed on the groove 25. Round parts are formed at upper and lower end parts 28 and 30 of the groove. Thus the steep change in configuration at the upper and lower end parts of the groove can be made to be a gentle configuration. Therefore, a gate film 31, which is formed in the next process, can be formed so as to have a uniform thickness. After the gate film 31 is formed, a polysilicon electrode 32 and an embedded layer 33 are sequentially formed by the conventional processes.
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