500 mA AlGaAs/GaAs power heterojunction bipolar transistor

The current-voltage characteristics of 500 mA AlGaAs/GaAs power heterojunction bipolar transistors are reported and the influence of case temperature on current handling capability and current gain are analysed. Current handling capabilities of 400-800 mA/mm per emitter periphery at different case temperatures have been successfully demonstrated using a low-doped GaAs layer as an emitter ballasting resistor to obtain a uniform current distribution over individual emitter fingers. A current gain of 50 at a collector current of 500 mA was realised at room temperature for three elementary devices bonded in parallel, each device comprised ten (5*25 mu m²) emitter fingers.