PURPOSE: To increase the capacitance by a method wherein a projection is formed instead of digging a groove in a semiconductor substrate.

CONSTITUTION: A projection 13 is formed on the surface of the Si substrate 11 by etching away the Si substrate surface except the projection part, using the mask of a resist. Next, field oxide films 12 are formed by means of the mask of an oxide film and a nitride film. Then, an Si substrate surface gate oxide film 14 is formed by thermal oxidation and patterning, and a polycrystalline Si is grown over the whole surface and patterned by phosphorus diffusion, thereby forming a charge accumulated gate electrode 15. An oxide film 16 is formed on the surface of the electrode 15, and a polycrystalline Si is grown over the whole surface and patterned by phosphorus diffusion, thereby forming a transfer gate electrode 17. After a bit line diffused layer 18 is formed by ion implantation, an oxide film 19 is formed. This manner can contrive to increase the capacitance and reduce the capacitor area by facilitating the manufacturing process with high accuracy.