| 摘要 |
PURPOSE:To make it possible to form projected and recessed parts on the surface of a polycrystalline silicon film in a stable and easy manner by forming a silicon oxide film whose film thickness is greater than that of a grain section on a grain boundary section of the polycrystalline silicon film and then etching the silicon oxide film and polycrystalline silicon film. CONSTITUTION:The surface if a polycrystalline silicon film 2 is esposed to oxygen plasma and slightly oxidized, which forms a silicon oxide film 5 on the surface of the polycrystalline silicon film 2. During this formation, the silicon oxide film 5 is formed on a grain boundary section 3 rather than a grain section 4. Then, the silicon oxide film 3 and a part of the polycrystalline silicon film 2 are etched with reactive ions, using HBr gas-based plasma which is anisotropic etching. Under this etching condition, the etching speed of the polycrystalline silicon film 2 is sufficiently large compared with the etching speed of the silicon oxide film 5. As a result, only the upper part of a clad section of the polycrystalline silicon film 2 can be removed by etching, which produced projected and recessed parts on the surface of the polycrystalline silicon film 2, then removes the silicon oxide film 5, thereby forming a number of projected and recessed parts with ease. |
