The pseudomorphic collector structure is known to allow enhanced collector transport, facilitating higher current cutoff frequencies at lower current densities and junction temperatures compared to traditional single heterojunction structures. The performance of a 0.25×3 μ m2 pseudomorphic heteojunction bipolar transistors achieves peak fT of 710 GHz (fMAX =340 GHz) at a collector current density of 20 mAμ m2. The same device achieves a fT fMAX of 540407 GHz at a reduced current density of 7.5 mAμ m2. The epitaxial structure employs a 12.5 nm strained InGaAs base and 55 nm InGaAs collector, and exhibits a Β of 115 and breakdown voltage of BVCEO =1.75 V.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)