| 摘要 |
PURPOSE:To obtain a device having an input protecting circuit, by which effects on electric characteristics is small at the time of normal operation and the sufficient limiting effect is obtained when a current is limited, by constituting a resistor for limiting the current by connecting a resistor region formed within a semiconducltor substrate and a resistor region formed on the semiconductor substrate in parallel. CONSTITUTION:P type impurities are ion-implanted from the surface of an N type epitaxial layer 20, and a P type semiconductor region 21, whose layer resistance is relatively high, is formed. Then, an insulating film 22 is formed on the surface. Thereafter, a thin polycrystal silicon film is selectively formed on the silicon oxide film 22. N type impurities are introduced, and a high concentration N type polycrystal silicon thin film region 23 is provided. Then a silicon oxide film 24 as an insulating film is formed on the entire surface. Opening parts 25 are provided in order to provide electrode parts at both ends of the P type impurity region 21 and the high concentration N type polycrystal thin film region 23. An electrode part 26-1 is connected to an input terminal, and another electrode 26-2 is connected to the base of an input transistor. The potential of an electrode part 27 is fixed at a specified potential, and an overcurrent limiting element in an input circuit is formed. |
