Abstract
The microwave and power performance of fabricated InF-based single and double heterojunction bipolar transistors (HBT's) is presented. The single heterojunction bipolar transistors (SHBT's), which had a 5000-angstroms InGaAs collector, had BV CE0 of 7.2 V and J C max of 2×10 5 A/cm 2 . The resulting HBT's with 2×10 μm 2 emitters produced up to 1.1 mW/μm 2 at 8 GHz with efficiencies over 30%. Double heterojunction bipolar transistors (DHBT's) with a 3000-angstroms InP collector had a BV CE0 of 9 V and J C max of 1.1×10 5 A/cm 2 , resulting in power densities up to 1.9 mW/μm 2 at 8 GHz and a peak efficiency of 46%. Similar DHBT's with a 6000-angstroms InP collector had a higher BV CE0 of 18 V, but the J C max decreased to 0.4×10 5 A/cm 2 due to current blocking at the base-collector junction. Although the 6000-angstroms InP collector provided higher f max and gain than the 3000-angstroms collector, the lower J C max reduced its maximum power density below that of the SHBT wafer. The impact on power performance of various device characteristics, such as knee voltage, breakdown voltage, and maximum current density, are analyzed and discussed.