| 摘要 |
PURPOSE:To obtain the capacities invariable to the voltages being applied to input terminal by covering part of wirings provided between input external lead-out electrodes and the gate electrodes of input transistors with a metal film which becomes of the same potential as that of substrate during use, via insulation film. CONSTITUTION:After a thick field oxide film 7 is deposited on a P type semiconductor substrate 9, it is opened with windows, where N type regions 2 to become wiring layers are diffusion formed. Next, a polycrystalline Si wiring layer 16 is formed to one end of the regions while being extended onto the film 7 and a polycrystalline Si gate electrode 4 is formed to the other end while being extended onto the gate oxide film 8. Thereafter, an insulation film 20 for forming a constant capacity of the input protecting device is deposited by being extended while burying therebetween and an Al external lead-out electrode 1 is formed to one end thereof and an Al film 19 on the insulation film 20 on the polycrystalline layer respectively. Then, the capacities 22, 24, 25 which do not depend upon the voltage being applied to the input terminal 10 are created in the wiring from the electrodes 1 to 4, thus the high voltage waveforms having been applied to the terminal are delayed and sufficiently smoothed. |
