InGaAs/InP DHBTs with 120-nm collector having simultaneously high f/sub /spl tau//, f/sub max//spl ges/450 GHz
InP/In/sub 0.53/Ga/sub 0.47/As/InP double heterojunction bipolar transistors (DHBT) have been designed for increased bandwidth digital and analog circuits, and fabricated using a conventional mesa structure. These devices exhibit a maximum 450 GHz f/sub /spl tau// and 490 GHz f/sub max/, which is the highest simultaneous f/sub /spl tau// and f/sub max/ for any HBT. The devices have been scaled vertically for reduced electron collector transit time and aggressively scaled laterally to minimize the base-collector capacitance associated with thinner collectors. The dc current gain /spl beta/ is /spl ap/ 40 and V/sub BR,CEO/=3.9 V. The devices operate up to 25 mW//spl mu/m/sup 2/ dissipation (failing at J/sub e/=10 mA//spl mu/m/sup 2/, V/sub ce/=2.5 V, /spl Delta/T/sub failure/=301 K) and there is no evidence of current blocking up to J/sub e//spl ges/12 mA//spl mu/m/sup 2/ at V/sub ce/=2.0 V from the base-collector grade. The devices reported here employ a 30-nm highly doped InGaAs base, and a 120-nm collector containing an InGaAs/InAlAs superlattice grade at the base-collector junction.