A bipolar transistor with a specific area resistance less than about 500 mOhms·mm2 comprises a first semiconductor region of a first conductivity type defining a collector region (2). A second semiconductor region of a second conductivity type defines a base region (3). A third semiconductor region of the first conductivity type defines an emitter region (4). A metal layer provides contacts (6, 7) to said base (3) and emitter regions (4). The metal layer has thickness greater than about 3 μm.