Patent ID: 7923751

Claim:
A bipolar transistor suitable for operation as a saturated switch comprising: a first semiconductor region of a first conductivity type defining a collector region; a second semiconductor region of a second conductivity type defining a base region; a third semiconductor region of said first conductivity type defining a emitter region; and a metal layer providing metal track contacts that directly contact the base region and the emitter region; wherein the emitter region defines a first surface, the base region extending to the first surface in locations defined by apertures through the emitter region, the metal layer overlying the first surface; wherein the bipolar transistor has a specific area resistance less than 500mOhms·mm 2 ; wherein the metal layer has a thickness that is substantially uniformly greater than 3 μm; and wherein voltage drops in the metal track contacts, which contact the base region and the emitter region, are reduced when the bipolar transistor is in an on state to distribute a voltage bias to a junction of the base region and the emitter region such that saturation resistance is reduced by an amount greater than 0% and up to 30% compared to the same bipolar transistor having a metal layer of thickness less than 3 μm.