Growth and characterization of novel multilayer heterostructures for the monolithic integration of resonant-cavity photodiodes and heterojunction bipolar transistors

We describe the layer structures, crystal‐growth conditions, and characteristics of novel multilayers in the InGaAlAs/InGaAs/InAlAs materials system for the monolithic integration of heterojunction bipolar transistors (HBTs) and resonant‐cavity photodiodes. The photodiodes are formed of the base and collector regions of the HBT layer. The use of a resonant cavity improves the quantum efficiency for an absorbing layer of given thickness. The HBTs had high current gains and well‐behaved Gummel plots. The absorption and photocurrent characteristics of the resonant photodiodes show a ∼100% enhancement at resonance.