Patent ID: 7939905

Claim:
A semiconductor device having an electrostatic breakdown protection from a surge current impressed between a first terminal and a second terminal, the semiconductor device comprising: a diode impressing a forward-bias current from the first terminal to the second terminal, the diode comprising an anode terminal and a cathode terminal of a P-N junction; and a bipolar transistor impressing a current in a direction from the second terminal to the first terminal under an ON state, a continuity between a collector terminal and an emitter terminal of the bipolar transistor being attained before a potential difference between the first terminal and the second terminal reaches such a level that the diode is broken down, wherein at least one of the diode and the bipolar transistor includes a buried region formed below and adjacent to a semiconductor region where the emitter terminal of the bipolar transistor or one of the anode and cathode terminals of the diode is formed, with a same conductivity type as the semiconductor region and an impurity concentration lower than an impurity concentration of the semiconductor region.