Scaled AlInAs/InGaAs and InP/InGaAs heterostructure bipolar transistors

Summary form only given. The authors report on Al_0.48In_0.52As/In_0.53Ga_0.47 and InP/In_0.53Ga_0.47As HBTs (heterojunction bipolar transistors), which demonstrate near-ideal lateral scaling and ultrahigh-speed performance. Abrupt emitter-base junction are used to realize high-energy electron injection and nonequilibrium transport in the base and collection depletion region. Current gains of beta =162 and 122 have been realized in AlInAs/InGaAs transistors with emitter stripe widths of 50 and 0.6 mu m, respectively. Microwave characteristics of the InP/InGaAs HBTs show and f_T=165 GHz, while preliminary results of the AlInAs/InGaAs devices show f_T=72 GHz, which is limited by the parasitics. Also demonstrated is the first successful high-speed scaling of III-V HBTs by achieving f_T>100 GHz in transistors with emitter stripe widths of less than 0.6 mu m. The high performance is due to the large conduction band Gamma -L (0.55 eV) and Gamma -X (1.15 eV) separation in the InGaAs base and collector.