| 摘要 |
PURPOSE:To reduce the creeping phenomenon of a low-concentration region into a channel region, to prevent a short-channel effect and to enhance the characteristic by a method wherein the low-concentration region on the side of the channel region of a drain is formed by impurities of a small diffusion-coefficient. CONSTITUTION:An N-channel MISFET acting as a memory cell is composed of the following: a gate-insulating film 9 composed of a silicon oxide film formed by the thermal oxidation of the surface exposed from a field insulating film 7 of a semiconductor substrate 1; a gate electrode 10 which is composed of a polycrystalline silicon film formed, e.g., by a CVD method and is constructed by laminating a refractory metal film of, e.g., Mo, W, Ta, Ti or the like or a silicide film of this metal on it; an n-type semiconductor region (low-concentration region) 11 constituting the side of a channel region of a source-drain region; an n<+> type semiconductor region (high- concentration region) 12 constituting the part which is separated from the channel region. The n-type semiconductor region 11 is composed of n-type impurities of a small diffusion-coefficient, e.g., arsenic (As), and its dose quantity is set at about 1X10<13> atoms/cm<2>. By using the arsenic, a creeping phenomenon under the gate electrode is reduced so that a short-channel effect can prevented. |
