InP DHBT technology for power amplifiers at mm-wave frequencies

An InP Double Heterojunction Bipolar Transistor (DHBT) technology is presented for millimeter-wave power amplifiers at E-band and higher frequencies. Single- and multi-finger transistors with 0.7μm emitter width and emitter lengths of 5, 7, 10μm are designed for high frequency and high power applications. The static and AC performances of the fabricated devices are discussed. Reported cutoff frequency and maximum oscillation frequency are ft=267GHz and fmax=450GHz for a 0.7×5μmP2 single-finger device, respectively. Results from large-signal measurements at 30 GHz are reported for single and 4-finger devices. Ballasted devices are introduced to improve thermal behaviour and to increase the limits of the safe operating area (SOA). The SOA is improved approximately by 75% for 4-finger devices with 0.7×10μm2 emitter. A fabricated monolithic microwave integrated circuit (MMIC) at E-band based on stacked InP DHBTs is presented and its performances reported to demonstrate the power capabilities of the technology.