| 摘要 |
PURPOSE:To increase the capacity per unit plane area of an effective capacitor, by forming a projection comprising a single-crystal semiconductor layer on a semiconductor substrate, and forming the capacitor on the surface thereof. CONSTITUTION:An SO2 mask film is removed by a wet etching means. In a capacitor forming region on the surface of a P-type silicon substrate, a P-type silicon projection 124, which comrises a P-type silicon epitaxial layer 24 and has the area of about 3X3mum square and the height of about 1-2mum, is made to remain. Then an SiO2 dielectric film 13 having a thickness of, e.g., about 200Angstrom , is formed on the surfaces of the silicon, i.e., the surfaces of the P-type silicon projection 124 and the silicon substrate 11 by a thermal oxidation method. Thereafter, a first polycrystalline silicon layer PA having a thickness of, e.g., about 3,000-4,000Angstrom , is formed on the substrate by a CVD method. An N-type impurities are introduced and conductivity is imparted. Then the first polycrystalline silicon layer PA is patterned, and the counter electrode of a capacitor, i.e., a cell plate 14 is formed. Thereafter, the exposed SiO2 dielectric film 13 is removed by a wet etching method and the like using fluoric acid liquid. |
