| 摘要 |
PURPOSE:To prevent a depletion layer from being extended in a semiconductor substrate and contract an element isolation region and improve characteristics of information holding by a method wherein insulating films are provided on the wall surfaces of a groove and two electrodes are provided in the trench and one of the electrodes is connected to the semiconductor region of a selective MISFET and the other electrode is connected to the semiconductor substrate. CONSTITUTION:On the whole surfaces of side walls of a groove 5 which reaches an n<+>type semiconductor substrate 1 from the surface of a p<->type epitaxial layer 2, insulating films 6 composed of silicon oxide films which are produced by oxidizing the p<->type epitaxial layer 2 or the n<+>type semiconductor substrate 1 are formed. A capacitance element is composed of electrodes 7 and 9 composed of polycrystalline silicon films and a dielectric film 8 composed of, for instance, a silicon oxide film. The upper end of the electrode 7 reaches the upper end of the groove 5 and the lower end of the electrode 7 is connected to the n<+>type semiconductor substrate 1. The electrode 9 is provided also on the upper part of the p<->type epitaxial layer 2 and a part of it is connected to an n<+>type semiconductor region 11 which is a part of the source and drain regions of a selective MISFET through an aperture 10 which is formed by selectively removing the dielectric film 8 on the p<->type epitaxial layer 2. |
