The attainment of high microwave output, up to 0. 4 W CW at 10 GHz, with GaAlAs/GaAs heterojunction bipolar transistors (HBTs) is discussed. In addition to high power, the HBTs displayed excellent power-added efficiency (48%) and power gain (7 dB). A key factor in obtaining these high powers and efficiencies is the ability to support high collector-emitter voltages without breakdown. Breakdown voltage was up to 23 V (BV//c//b//o) in the devices reported here. The experimental data are in good agreement with a theoretical model of I-V characteristics near breakdown. The cutoff frequency f//t was found to vary with V//c//e as expected for electron drift at a saturation velocity of 1 multiplied by 10**7 cm/s across the base-collector depletion region.
|Number of pages||4|
|Journal||Technical Digest - International Electron Devices Meeting|
|State||Published - 1 Dec 1987|