| 摘要 |
PURPOSE:To lower punch-through withstanding voltage, and to protect a thin insulating film by surge voltage and a junction from breakdown by disposing a diffusion layer having concentration different from a source to a channel section for a drain in a MOS transistor for an output circuit and an adjacent section. CONSTITUTION:A field oxide film 22 and a gate oxide film 22' are formed, and an opening 23 is bored to the oxide film in a section as a drain in a transistor. Polycrystalline silicon 24 containing phosphorus is evaporated as a gate material and an N type impurity as a wiring, and an N<+> diffusion layer 25 having high concentration (approximately 10<20>cm<-3>) is shaped deeply through thermal diffusion. According to a manufacturing process for a known LDD structure transistor, an N<+> diffusion layer 29 and an N<-> diffusion layer 30 are shaped in a source region while an inter-layer insulating film 26, metallic wirings 271, 272 by aluminum, etc. and an insulating film 28 are formed, thus obtaining the transistor. The thin insulating film by surge voltage and a junction can be protected from breakdown by the presence of the high-concentration diffusion layer 25. |
