Microwave characteristics of a carbon-doped base InP/InGaAs heterojunction bipolar transistor grown by chemical beam epitaxy

The first high-speed operation of an InP/In_0.53Ga_0.47As heterojunction bipolar transistor (HBT) using a highly carbon-doped base is reported. A base carrier concentration of 7*10¹⁹/cm³ was achieved by chemical beam epitaxy (CBE). To the authors´ knowledge, this is the highest doping level reported using carbon. The f_T and f_max of the HBT with two 1.5*15 mu m² emitter fingers were 115 GHz and 51 GHz respectively, at I_C=60 mA and V_CE=2.0 V. These results indicate the significant potential of highly carbon-doped-base InP/InGaAs HBTs for high-speed applications.