Patent ID: 7297993

Claim:
A bipolar transistor, including: a substrate; at least one pair of semiconductor mesa portions provided on said substrate with a space therebetween; a base layer on each semiconductor mesa portion; a base electrode contacting and bridging between each base layer of each pair of semiconductor mesa portions; and a base wiring, wherein, said base layers of a semiconductor mesa portion pair are spaced from each other by a first predetermined distance, said base electrode extends over said first predetermined distance and forms a floating extension between said base layers, said floating extension includes a contact portion between said base layers where said base electrode can be connected to said base wiring over said space below said base electrode and between said corresponding mesa portions, said floating extension includes a portion which spatially rises uprightly above said space on an inner side by a second predetermined distance with respect to a side edge of each of said base layers, and said second predetermined distance is selected to be equal to or greater than 1.0 μm from said side edge of each of said base layers to decrease a leak current between a collector and said base layer.