Abstract: A method for manufacturing semiconductor memory device is capable of forming a first diffused layer in a memory cell portion and a second diffused layer in a peripheral portion in respective optimum conditions independently of each other without increasing the masking costs. The method includes steps of forming a polysilicon film covering the entire main surface of the substrate, patterning the polysilicon film in the memory cell portion without patterning the polysilicon film in the peripheral portion, performing a first ion implantation on the main surface to form the first diffused layer in the memory cell portion, while keeping the peripheral portion covered with the second polysilicon film, patterning the second polysilicon film in the peripheral portion to form a gate electrode, and performing a second ion implantation to form the second diffused layer in the peripheral portion.

Abstract: A method for fabricating a semiconductor device includes steps of: (a) forming a MIS type transistor having a gate electrode and a first source/drain region and a second source/drain on a semiconductor substrate, (b) forming a contact hole by causing an insulating layer and a pad material layer to grow over the semiconductor substrate. and removing selectively the insulating layer and the pad material layer to expose the first source/drain regions, (c) forming a conductive plug, which fills inside the contact hole, by forming a first conductive material layer and etching back this layer in such a way as to leave this layer only in the contact hole, and (d) forming a capacitor which has a first electrode being in contact with the conductive plug and extending in a cantilever-like form from the conductive plug, a dielectric film covering a surface of the first electrode, and a second electrode surrounding the first electrode through the dielectric film.