Abstract: A bipolar transistor and a diode are incorporated in a semiconductor integrated circuit device, and an emitter electrode is constituted by lower and upper doped polysilicon films sandwiching an oxygen-leakage film which tunnels minority carriers of the base therethrough at higher probability than the majority carriers so as to enhance the emitter injection efficiency, thereby allowing a designer to increase the base width and the distance from the p-n junction between the anode and the cathode for improving the breakdown voltage of the diode without sacrifice of the current amplification factor.