InGaP/GaAs ballistic collection transistors with buried polycrystalline GaAs under base electrode

Abstract

InGaP/GaAs ballistic collection transistors, with buried polycrystalline GaAs under the base electrode, have been fabricated by using gas-source molecular beam epitaxial growth on SiO2-patterned GaAs substrates. Heavy C-doping in the base led to a high maximum oscillation frequency of 170 GHz while maintaining a high cutoff frequency of 170 GHz. Owing to the reduction in base-collector capacitance, maximum stable gain was increased by 2.3 dB compared to that of transistors without polycrystalline GaAs.