35-40 GHz monolithic VCO's utilizing high-speed GaInP/GaAs HBT's

Design, fabrication and performance of Ka-band voltage-controlled oscillators (VCO's) are described. High-speed self-aligned GaInP/GaAs heterojunction bipolar transistors (HBT's) as active devices and varactor diodes using the basecollector junction of the HBT structure are implemented in the VCO's. The HBT's have an emitter area of 2 x 1.5 micrometers x 10 micrometers and incorporate a highly carbon doped base layer and a thin GaInP hole barrier. Oscillators with center frequencies of 35, 37, and 40 GHz exhibit tuning ranges of up to 1 GHz and typical output powers of 1-3.5 dBm. Best measured phase-noise at 1 MHz off carrier is -107 dBc/Hz