| 摘要 |
PROBLEM TO BE SOLVED: To prevent the formation of unevenness in an RIE process on one main surface side of a substrate, by forming an oxide film on the surface of the substrate, and roughening the surface by a reactive ion etching (RIE) method. SOLUTION: The semiconductor substrate consisting of silicon, etc., containing one conductivity type semiconductor impurity is prepared. A silicon substrate is dipped in hydrofluoric/nitric acid and a sodium hydroxide aqueous solution for removing the slice damage of the surface section of the silicon substrate, and etched in approximately 15 μm. The silicon substrate is washed by water, and dipped in an approximately 10% HF aqueous solution for several sec, an oxide film of a surface is removed, the substrate is washed by water, and immersed in an NaOH aqueous solution for several sec, and stained films may also be taken off. The processes of HF and NaOH are repeated at several times until a surface completely repels water. The substrate is washed by water, and introduced into a liquid having oxidation force such as nitric acid, sulfuric acid, etc., for several min, and an oxide film is formed uniformly on the substrate surface. When RIE is conducted, the oxide film is etched equally and irregularities begins to be formed simultaneously extending over the whole surface, thus forming irregularities without unevenness. |
