Abstract: The base-collector capacitance in a heterojunction bipolar transistor (HBT) (50) is reduced, thereby providing increased cutoff frequency and power gain, by eliminating a portion of a collector contact layer (54) which normally underlies a base electrode (66). A similar effect may be produced by forming the collector contact layer (54) such that it initially extends into the area (54c) under the base electrode (66), and subsequently rendering the collector contact layer (54) in this area (54c) semiinsulative by proton bombardment. A ballast resistor layer (70) is formed between an emitter layer (62) and an overlying emitter electrode (68) to prevent thermal runaway and hot spot formation. A plurality of the HBTs (50) may be arranged in a distributed amplifier configuration (80) including contact electrode bus lines (84,88) having a geometry designed to provide high thermal efficiency, and input and output circuit matching characteristics.