6-GHz AlInAs/GaInAs/InP DHBT's grown by MOVPE+MBE

N-p-n AlInAs/GaInAs/InP double-heterojunction bipolar transistors (DHBTs) have been fabricated. They operated with common emitter current gains to over 125 and cutoff frequencies (both f/sub T/ and f/sub max/) of approximately 60 GHz. The epitaxial structures for these devices were grown in a two-step sequence utilizing MOVPE for the InP collector structure followed by solid source MBE for the growth of the GaInAs base and AlInAs emitter structures. The DHBTs were fabricated as emitter-up, mesa transistors with self-aligned base contacts. The MOVPE-grown portion consisted of a 690-nm GaInAs (n/sup +/=1*10/sup 19/ cm/sup -3/) subcollector with a 390-nm-thick InP collector doped at n=1.4*10/sup 16/ cm/sup -3/. The remaining epitaxy was grown by solid source MBE.