| 摘要 |
PURPOSE:To manufacture a capacitance element capable of increasing capacitance without increasing the thickness of a polycrystalline Si film, by processing the polycrystalline Si film turning to a storage node, so as to be in an uneven type. CONSTITUTION:When 50-80%, e.g. of the thickness of a polycrystalline Si film 18 is subjected to dry etching, the part on which fine particles 19 of Si dioxide are stuck turns to a mask for dry etching, so that only the part on which the particles 19 are not stuck is selectively etched. By etching the polycrystalline Si film 18 for a specified time with mixed solution of hydrofluoric acid and nitric acid, the fine particles 19 of Si dioxide are lifted off and selectively eliminated. On this polycrystalline Si film 18 processed in an uneven type, an capacitor insulation film 20 like Si nitride is formed by vapor phase epitaxy. Thereon a third polycrystalline Si film 21 is formed by vapor phase epitaxy, and impurities are diffused into the film 21 to increase conductivity, thereby forming other side electrode of a capacitance element. By processing the film 18 in an unenen type wherein the diameter is 100-1000Angstrom , the capacitance is increased without increasing a step-difference at the time of depositing the film 21. |
