| 摘要 |
PURPOSE:To increase a semiconductor device in surface area by a method wherein polysilicon small pieces are provided as the lower electrode of a capaci tor and turned into large aggregates by ion implantation. CONSTITUTION:A contact hole 13 of an insulating film 12 on a board 11 is filled with a conductive film 14, and when a polysilicon film 15 is provided as the lower electrode of a capacitor, the polysilicon film 15 is not so well grown under prescribed conditions and grows into small pieces. Then, when impurities are injected into all the surface of the polysilicon film 15, the small pieces are joined together into a film 15a composed of larger aggregates of polysilicon. Then, only a part of the polysilicon film 15a to serve as the lower electrode is left unremoved by etching and then dipped into a hydrofluoric acid solution to remove the insulating film 12 to a certain extent, whereby the polysilicon film 15a serving as the lower electrode is kept in a floating state, and the recessed parts of the lower electrode 15a grow into through-holes or the like, so that the lower electrode 15a can be enhanced in surface area. By this setup, a semiconductor device of this constitution can be improved in capacitance. |
