| 摘要 |
PURPOSE:To form a recessed groove of very large surface area against plane area, and to form a capacitor of a large capacitance value by increasing the opposing area of the upper and the lower electrodes. CONSTITUTION:A silicon oxide film 4 is formed on the surface of the first polycrystalline silicon film 3, the second polycrystalline silicon film 5, containing impurities, is formed on the above-mentioned silicon oxide film 4, and a silicon crystal grains 5a are formed by selectively etching the crystal grain boundary of the second polycrystalline silicon film 5 using hot phosphoric acid. The silicon oxide film 4 is etched using the formed silicon crystal grains 5a as a mask, and recessed grooves 3a are formed on the surface of the first polycrystalline silicon film 3 by conducting an etching treatment on the silicon oxide film 4 using the formed silicon crystal grains 5a as a mask and also by conducting an anisotropic etching treatment on the first polycrystalline silicon film 3 using the etched silicon oxide film 4 as a mask. |
