INTEGRATION OF GAINP GAAS HETEROJUNCTION BIPOLAR-TRANSISTORS AND HIGH-ELECTRON-MOBILITY TRANSISTORS/

Integration of carbon-doped GaInP/GaAs heterojunction bipolar transist ors (HBT's) and high electron mobility transistors (HEMT's) is demonst rated by growing an HBT on the top of a HEMT. A current gain of 60, a cutoff frequency of 59 GHz and a maximum oscillation frequency of 68 G Hz were obtained for a 5 x 15 mu m(2) self-aligned HBT. The HEMT with a gate length of 1.5 mu m has a transconductance of 210 mS/mm, a cutof f frequency of 9 GHz and a maximum oscillation frequency of 22 GHz. It is shown that the GaInP/GaAs HBT on the HEMT is a simple Bi-FET techn ology suitable for microwave and mixed signal applications.