| 摘要 |
PURPOSE:To obtain a buried type gate electrode in a semiconductor device by forming a recess on the surface of an Si substrate, covering the wall surface and the bottom surface with an insulating film, filling an electrode material therein and covering it with an insulating film. CONSTITUTION:An SiO2 film 24, an Si3N4 film 26 and a Pt film 28 are laminated on a p type Si substrate 22, are opened with a hole, a recess 30 is etched on the substrate, and scratches are formed on the ends of the laminated films. The surface of the recess is covered with an SiO2 film 32. It is effective if a p type impurity layer is formed beforehand under the film 32. Subsequently, impurity-added amorphous Si 34 is covered from a vertical direction. Then, Pi 28 is selectively etched with aqua regia, and the amorphous Si film 34 is lifted off. Successively, with the Si3N4 film as a mask it is thermally oxidized, and is covered with an SiO2 film 36. At this time the amorphous Si becomes a polysilicon (gate electrode) 38. When the films 26 and 24 are thereafter etched, a buried type MOS gate can be completed. According to this configuration, a buried type insulating gate having a flat surface can be simply formed accurately. |
