Abstract: A DRAM having a stacked-type capacitor whose structure has a capacitor lower electrode, a first impurity region connected thereto, a third impurity region formed by thermal diffusion of impurities included in the capacitor lower electrode, is disclosed in which an end portion of a third impurity region on the side of gate electrode can be effectively prevented from being extended from an end portion of a first impurity region on the side of gate electrode in the subsequent heat treatment. In the DRAM, an epitaxial silicon layer 8 or a polycrystalline silicon layer 28 having an impurity concentration lower than that of capacitor lower electrode 9 is interposed between capacitor lower electrode 9 and a first impurity region 3b, so that thermal diffusion of impurities in capacitor lower electrode 9 is reduced as compared with the conventional case.

Abstract: A semiconductor device includes a first neutral impurity layer formed to a predetermined depth from a surface of a semiconductor substrate in a channel region that is interposed between source/drain regions and located below a gate electrode, and a second neutral impurity layer having a higher concentration than that of the first neutral impurity layer and formed to surround lower portions of the source/drain regions except for the channel region. Scattering of neutral impurities in the first neutral impurity layer suppresses generation of hot carriers, and the second neutral impurity layer suppresses diffusion of impurities in the source/drain regions in thermal processing. The second neutral impurity layer is formed by implanting neutral impurities obliquely after formation of the gate electrode.