| 摘要 |
PURPOSE:To enable the inhibition of hot carrier injection by relaxation of the electric field of the depletion layer spreading in a substrate in the neighborhood of a drain by a method wherein the impurity concentration of the part of a drain region opposed to a source region is made lower than that of the remaining part. CONSTITUTION:An Si oxide film 13 as a MIS structural insulation film is formed, and a polycrystalline Si film 14 is deposited, which is then changed into a conductor by phosphorus diffusion from the surface at a high temperature. The oxide film 13 is left only under a gate electrode 15, and the oxide film on the surface of the substrate except a field oxide film 12 is removed, resulting in the formation of 16 as a protection film for the substrate surface and the side and upper surfaces of the gate electrode. The entire surface is coated with a thin film 18 of Si nitride, which film is then patterned so as to cover the drain region. Introduced impurities 17 and 20 turn into the source region 23 and the drain region, n type impurity diffused regions, by heat treatment after removal of the Si nitride film 18. An interlayer film 24 of phospho-silicate glass is deposited; thereafter, the interlayer film is opened on the source and drain, and the gate electrode and aluminum wirings 25, 26, and 27 are formed. |
