HIGH-PERFORMANCE ZN-DOPED-BASE INP/INGAAS DOUBLE-HETEROJUNCTION BIPOLAR-TRANSISTORS GROWN BY METALORGANIC VAPOR-PHASE EPITAXY

We report the successful growth of high-quality InP/InGaAs double-heterojunction bipolar transistors with heavily Zn-doped base layers (p=4X10(19) cm-3) using metalorganic vapor phase epitaxy. Interrupting the growth for 30 min after growing a heavily Si-doped subcollector (n=2X10(19) CM-3) is shown to eliminate the excessive nonequilibrium group III interstitials that enhance abnormal Zn diffusivity in the subsequently grown base region. Gummel plots of the fabricated microwave transistors show that they have ideal turn-on characteristics in spite of having only 5-nm-thick undoped spacer layers inserted between the emitter and base. The transistors obtain a maximum oscillation frequency f(max) of 178 GHz and a current gain cutoff frequency f(T) of 126 GHz.