| 摘要 |
PURPOSE:To make small an occupied area by holding satisfactorily the protective function at the same time by a method wherein when a diffused layer resistor which is the input protective device is connected to a transistor intended to be protected, the protective device is formed on the diffused layer comprising a high resistance layer and low resistance layer. CONSTITUTION:A gate of a protected transistor T2 is connected with a transistor T2 for cramping a surge voltage and the diffused layer resistor R for making the wave form of the surge voltage gentle. In this construction, the resistor R is composed of the diffused layer comprising the high resistance layer and low resistance layer. Namely, an oxidized film 2 is cover-attached to a P type Si substrate and a window is opened into which phosphorous ions are injected and then, a press-in diffusion is applied thereto to first form an N type high resistance layer 3. In the next place, after a window is perforated again into the oxidized film which has been grown at this time, corresponded to the central part of the layer 3, and an N type low resistance layer 4 which is projected from the inside of the layer 3 into the substrate 1 is formed by the diffusion, an opening is formed in the film 2 and a metal electrode 5 is cover-attached to the layer 3 while being extended over the film 2. |
