Y. Matsuoka et al., HIGH-EFFICIENCY OPERATION OF ALGAAS GAAS POWER HETEROJUNCTION BIPOLAR-TRANSISTORS AT LOW COLLECTOR SUPPLY VOLTAGE/, Electronics Letters, 29(11), 1993, pp. 982-984
High-f(max) (> 160 GHz) AlGaAs/GaAs heterojunction bipolar transistors
are developed using power-oriented layer structures and a selfalignme
nt fabrication technology characterised by a base-metal overlaid struc
ture. The fabricated power transistors tested at 2.6 GHz yield maximum
power-added efficiencies of 69 and 60% at low supply voltages of 3 an
d 1.5 V, respectively.