Semiconductor device having field effect transistor connected at gate electrode to protective junction diode discharging in the presence of light

摘要

A gate electrode of a field effect transistor is charged during a plasma process, and a gate oxide layer is liable to be damaged; a protective junction diode is connected to the gate electrode of the field effect transistor, and is radiated with light during the plasma process so as to increase leakage current passing through the p-n junction; the leakage current is increased before the breakdown of the protective junction diode so as to prevent the gate oxide layer from the electric charge, and the breakdown voltage is higher than a test voltage applied to the gate electrode during a diagnosis on the gate oxide layer so that the manufacturer exactly diagnoses the semiconductor device.