SCALED ALINAS/INGAAS AND INP/INGAAS HETEROSTRUCTURE BIPOLAR-TRANSISTORS

Summary form only given. The authors report on Al0.48In0.52As/In0.53Ga0.47As and InP/In0.53Ga0.47As HBTs (heterojunction bipolar transistors), which demonstrate near-ideal lateral scaling and ultrahigh-speed performance. Abrupt emitter-base junctions are used to realize high-energy electron injection and nonequilibrium transport in the base and collection depletion region. Current gains of β = 162 and 122 have been realized in AlInAs/InGaAs transistors with emitter stripe widths of 50 and 0.6 μm, respectively. Microwave characteristics of the InP/InGaAs HBTs show and fT = 165 GHz, while preliminary results of the AlInAs/InGaAs devices show fT = 72 GHz, which is limited by the parasitics. Also demonstrated is the first successful high-speed scaling of III-V HBTs by achieving fT > 100 GHz in transistors with emitter stripe widths of less than 0.6 μm. The high performance is due to the large conduction band Γ-L (0.55 eV) and Γ-X (1.15 eV) separation in the InGaAs base and collector.