| 摘要 |
PURPOSE:To curtail a production process and also to obtain a high reliability of input protecting device at low cost by carrying out a diffusion to a Zener diode and a diffusion to a channel stopper at a time. CONSTITUTION:An oxidized film 21 on a p-type Si substrate 20 is etched with a nitrified film 22 as a mask, and a p-layer 23 is diffused and treated at high temperature to obtain a channel stopper 25 and an isolated layer 24. The films 21, 22 are removed, an oxidized thin film is provided newly, and a poly-Si film is placed thereon to form a gate electrode 26 and a gate oxidized film 27 selectively. Next, an opening is provided in the oxidized film 24, source and drain 28, 28' and an n-layer of input protective element are formed through P diffusion, and the poly-Si 26 is made to work at low resistance. Then, Zener diode is formed with layers 29 and 30. It is further covered with oxidized films 31, 31', 31'', 32, a window is provided selectively to form an input terminal 33 and wirings 34, 34', 34'' finally. According to this method, a production process is curtailed reasonably as compared with a conventional process, and a device strong against input rupture and high in reliability is obtainable at a moderate cost. |
