| 摘要 |
PURPOSE:To produce semiconductor elements from breakdown by a method wherein an impurity region of one conductivity type, an impurity region of the opposite conductivity type, an insulating film for a gate, and a gate electrode are provided. CONSTITUTION:In the event an excess voltage is inputted from an external terminal, or in the vent the potential of an impurity region 3 in floating conditions rises for the potential difference between a gate electrode 8 and the impurity region 3 to exceed the threshold voltage of a MOSFET 11, the MOSFET 11 is turned on. Accordingly, the electric charge resulting from the excess voltage applied to an input terminal is discharged to impurity regions 4 and 1, for the excess voltage to be effectively absorbed. An insulating film 6 formed thick enables the threshold voltage of the MOSFET 11 to be set with ease at a value higher than the power source voltages at which inner circuit elements function. With the device being designed as such, internal semiconductor elements are protected from breakdown due to excess voltage such as statics, etc. |
