| 摘要 |
PURPOSE:To enable high precision working and improve yield, by leaving a silicon nitride film in a recess, in order to discriminate a side contact part out of side walls of a trench formed in an Si substrate from a part for forming an oxide film for capacitor isolation which film electrically isolates a first electrode from the silicon substrate. CONSTITUTION:A silicon nitride film 21 is deposited on a diffusion layer 4 for connection on which a recess is formed, and left in the recess of the layer 4 by anisotropically etching the film 21 and an oxide film 2 for element isolation. A trench is formed in an Si substrate 1 by using a first oxide film 5 as mask material, and an oxide film 6 for capacitor isolation is formed on the side surface and the bottom surface. The silicon nitride film 21 left in the recess is selectively eliminated. Conductive material is deposited in the trench, anisotropically etched, left on the side wall part of the trench, and turned into a first electrode. A capacitor dielectric film, a second electrode, and a second oxide film are deposited in order. Unnecessary parts of the first oxide film 5 are eliminated, and the Si substrate 1 is exposed, thereby completing a capacitor part. |
