Semiconductor memory device and a process for producing the same

摘要

Dynamic RAM having memory cells, each of the memory cells having a capacitor with the electrode comprised of a first semiconductor region of a first type of conductivity formed in a substrate of second conductivity type. The first semiconductor region is formed by introducing impurities using a mask comprising (1) a nitride film which is deposited so as to define part of the shape of the capacitor. An oxide film, formed by thermal oxidation of the substrate, defines the shape of the memory cells, and each of the memory cells further have at least a second semiconductor region of a second type of conductivity formed between and under the electrodes, the shape thereof being defined by the nitride film and the oxide film that is formed by thermal oxidation.