Growth and Characterization of High-Speed Carbon-Doped-Base InP/InGaAs Heterojunction Bipolar Transistors by Metalorganic Chemical Vapor Deposition

The dependences of the hole concentration and hydrogenation ratio in C-doped InGaAs on growth parameters such as growth temperature, V/III ratio, and CBr 4 flow rate are clarified. The hydrogenation ratio is shown to increase with increasing carbon concentration in InGaAs. Several annealing procedures in different ambients and with different cap layers are examined to establish a procedure to effectively re-activate hydrogenated carbons in InGaAs base of heterojunction bipolar transistor (HBT) structure. It is revealed that the re-hydrogenation of C acceptors at the growth of emitter layer determines the final hole concentration in the base layer. With an annealing in H 2 with a growth interruption at the emitter/base interface, an as-grown hole concentration of 1.1×10 19 /cm 3 is obtained in the device structure. An HBT with a 1.6×9.6-µ m 2 emitter area exhibits f T and f max values of 185 and 105 GHz.