Collector-up HBT's fabricated by Be+and O+ion implantations

A novel collector-up (C-up) GaAs/AlGaAs heterojunction bipolar transistor (HBT) has been developed and initial device results presented. This device has its extrinsic base defined by Be + and O + implantations. The combination of Be + / O + implantations and heat-pulse annealing is leading to a considerable reduction in the parasitic current and capacitance in the extrinsic base region. Improved device structure and performance expected from this device are discussed in detail.