Double heterojunction AlxGa1-xAs/GaAs bipolar transistors (DHBJT´s) by MBE with a current gain of 1650

Double heterojunction AlGaAs/GaAs bipolar junction transistors (DHBJT´s) grown by molecular beam epitaxy (MBE) were fabricated and tested. Devices with 0.2-µm and 0.1-µm base thicknesses exhibited common emitter current gains of up to 325 and 1650, respectively, in a wide range of collector currents. To obtain such high current gains, growth conditions had to be optimized and controlled. These high current gains, compared with the previous best value of 120 obtained in a MBE-grown transistor, make the HBJT´s very promising for low-power high-speed logic application.