| 摘要 |
PURPOSE:To prevent generation of a short-circuit between a polycrystalline silicon and a semiconductor substrate and to contrive improvement in reliability of the title input protective circuit by a method wherein a wide-widthed polycrystalline silicon film having a floating state is formed between the polycrystalline silicon, as the series resistance element of the input protective circuit, and the semiconductor substrate. CONSTITUTION:An oxide film 2 is formed on a semiconductor substrate 1, and a floating-state polycrystalline silicon film 3, which is electrically connected to nowhere, is formed thereon. An interlayer insulating film 4 is provided on the polycrystalline silicon film 3, and a series resistance element 5 consisting of polycrystalline silicon, which is series-inserted into an input circuit, is provided on the interlayer insulating film 4. Even when dielectric breakdown is generated by the concentration of an electric field in the vicinity of the series resistance element 5 when high voltage is applied to a signal input terminal by static electricity, the interlayer insulating film 4 is broken down and there occurs a short-circuit only between the film 4 and the polycrystalline silicon film 3, and the short-circuit does not reach the semiconductor substrate 1.
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