Semiconductor integrated circuit device and a manufacturing method for the same

Abstract

In a manufacturing method for a semiconductor device, a first impurity diffusion layer for a low impurity concentration drain of a second conductivity type is formed within a semiconductor layer of a first conductivity type, and a second impurity diffusion layer for a high impurity concentration drain of the second conductivity type is formed adjacent to the first impurity diffusion layer, with the second impurity diffusion layer having a higher impurity concentration than the first impurity diffusion layer. An interlayer insulating film is formed on the semiconductor substrate layer. A drain extension region having a high thermal conductivity is formed on a surface of the first impurity diffusion layer. A contact hole is formed through the interlayer insulating film and up to the second impurity diffusion layer. A wiring metal layer is then deposited into the contact hole to form therein a drain electrode that is electrically connected to the second impurity diffusion layer and that is disposed apart from and not in contact with the drain extension region.