| 摘要 |
PURPOSE:To obtain a ROM capable of electrically writing/erasing composed of a floating gate MOS FET by a method wherein a trench is formed an Si substrate surface by dry etching, a gate insulating film is formed on the trench side surface, a first poly Si film is formed on the gate insulating film by CVD method, thereon an insulating film is formed, and second poly Si film is formed on the insulating film. CONSTITUTION:A trench part 2 is formed from the surface of an Si substrate 1 by photolithography and dry etching; in the inner surface of a trench part 2 including at least the side wall, a first insulating film 3 is thinly formed by thermal oxidation and the like; a first poly Si film 4 is formed by CVD method and the like; on the the surface of the first poly Si film 4, a second insulating film 5 is formed by thermal oxidation and the like; on the surface of second insulating film 5, a second poly Si film 6 is formed by CVD method and the like. The second poly Si film 6 formed in this manner is formed so as to fill the inside of the trench, and then photo-etched in a desired shape. |
