Semiconductor device comprising a bipolar transistor and method of production of the same

摘要

A semiconductor device is disclosed, in which a stable resistive contact having low resistance can be achieved in a base contact region, without reducing the emitter-base breakdown voltage and the current gain. In this semiconductor device, a p<++>-type base contact layer 8, having an impurity concentration which is larger than that of a p<+>-type base layer 5, is formed in a region, separated by a predetermined distance from an n<+>-type emitted layer 7, on the main surface of the p<+>-type base layer 5. The p<++>-type base contact layer 8 having a high concentration consequently does not come in contact with the n<+>-type emitter layer 7, and the current gain and the emitter-base breakdown voltage are furthermore not decreased. Since the p<++>-type base contact layer 8 is formed in such a way that it has a diffusion depth which is shallower than that of the n<+>-type emitter layer 7, the lateral extent of the p<++>-type base contact layer 8 can be decreased. The side face of the p<++>-type base contact layer 8 having a high concentration can therefore effectively be prevented from coming into contact with the side face of the n<+>-type emitter layer 7 even when the elements are made smaller. <IMAGE>