| 摘要 |
PURPOSE:To contrive to augment the value of a capacity to be formed in a certain plane by a method wherein the capacity forming part is formed in such a way as to form a roughness on the surface of the semiconductor substrate by a selective oxidizing method. CONSTITUTION:In a semiconductor substrate 301, a surface oxide film 302 is formed for forming recess parts in the capacity forming part, and after that, a silicon nitride film 303 is adhered by a CVD method, and the surface oxide film 302 and the silicon nitride film 303 are processed in the desired pattern so as to be able to provide the recess parts. After that, a selective oxidation is performed, the silicon nitride film is removed, and moreover, the surface oxide film and the selective oxide film are removed. After the recess parts 304 are formed in the surface of the semiconductor substrate, a surface oxide film 303 necessary for a selective oxidation for element isolation is formed, a silicon nitride film 306 is adhered by a CVD method, and the surface oxide film 305 and the silicon nitride film 306 are processed in the desired pattern so as to be able to provide the element isolation regions. After that, the silicon nitride film and the surface oxide film are removed and after an oxide film 308, which is used as the insulating film for forming the capacity, is formed, a first-layer wiring material layer 309 is adhered. By this method, the area of a part of the surface of the silicon substrate, where is the capacity forming part, is augmented and a capacitance value of about 25% or more to the total area of the surface can be secured. |
