Power performance of InP-based single and double heterojunction bipolar transistors

The microwave and power performance of fabricated InP-based single and doub le heterojunction bipolar transistors (HBT's) is presented. The single hete rojunction bipolar transistors (SHBT's), which had a 5000-Angstrom InGaAs c ollector, had BVCE0 of 7.2 V and J(Cmax) of 2 x 10(5) A/cm(2). The resultin g HBT's with 2 x 10 mu m(2) emitters produced up to 1.1 mW/mu m(2) at 8 GHz with efficiencies over 30%, Double heterojunction bipolar transistors (DHB T's) with a 3000-Angstrom InP collector had a BVCE0 of 9 V and J(Cmax) of 1 .1 x 10(5) A/cm(2), resulting in power densities up to 1.9 mW/mu m(2) at 8 GHz and a peak efficiency of 46%. Similar DHBT's with a 6000-Angstrom InP c ollector had a higher BVCE0 of 18 V, but the J(Cmax) decreased to 0.4 x 10( 5) A/cm(2) due to current blocking at the base-collector junction. Although : the 6000-Angstrom InP collector provided higher f(max) and gain than the 3000-Angstrom collector, the lower J(Cmax) reduced its maximum power densit y below that of the SHBT wafer. The impact on power performance of various device characteristics, such as knee voltage, breakdown voltage, and maximu m current density, are analyzed and discussed.