Demonstration of aluminum-free metamorphic InP/In0.53Ga0.47As/InP double heterojunction bipolar transistors on GaAs substrates

We report, for the first time, the successful fabrication of aluminum-free metamorphic (MM) InP/In-0.53 Ga0.47As/InP double heterojunction bipolar transistors (DHBTs) on GaAs substrates with a linearly graded InxGa1-xP buffer grown by solid-source molecular beam epitaxy (SSMBE), Device with 5 x 5 mu m(2) emitter displays a peak current gain of 40 and a common-emitter breakdown voltage (BVCEO) higher than 9 V, a current gain cut-off frequency (f(T)) of 48 GHz and a maximum oscillation frequency (f(max)) of 42 GHz, A minimum noise figure of 2.9 dB and associated gain of 19.5 dB were measured at a collector current level of 2.6 mA at 2 GHz. Detailed analysis suggests that the degradation of the base-emitter heterojunction interface and the increase of bulk recombination are the most probable causes for the poorer device performance of the current metamorphic HBTs compared to the lattice-matched HBTs.