0.5 THz Performance of a Type-II DHBT With a Doping-Graded and Constant-Composition GaAsSb Base
A type-II GaAsSb Double Heterojunction Bipolar Transistor (DHBT) with an AlInP emitter, doping-graded GaAsSb base, and InP collector has been grown by molecular beam epitaxy. The 0.38 μm emitter devices have been fabricated by a triple-mesa wet etch process and demonstrated f<sub>T</sub>/f<sub>MAX</sub>=470/540 GHz at J<sub>C</sub>=5.1 mA/μm<sup>2</sup> and V<sub>CB</sub>=0.65 V. This performance is comparable with composition-graded base devices with similar emitter width.