InGaAs-InP metamorphic DHBTs grown on GaAs with lattice-matched device performance and f/sub /spl tau//, f/sub max/>268 GHz

InP-In/sub 0.53/Ga/sub 0.47/As-InP double heterojunction bipolar transistors (DHBTs) were grown on a GaAs substrate using a metamorphic buffer layer and then fabricated. The metamorphic buffer layer is InP - employed because of its high thermal conductivity to minimize device heating. An f/sub /spl tau// and f/sub max/ of 268 and 339 GHz were measured, respectively - both records for metamorphic DHBTs. A 70-nm SiO/sub 2/ dielectric sidewall was deposited on the emitter contact to permit a longer InP emitter wet etch for increased device yield and reduced base leakage current. The dc current gain /spl beta/ is /spl ap/35 and V/sub BR,CEO/=5.7 V. The collector leakage current I/sub cbo/ is 90 pA at V/sub cb/=0.3 V. These values of f/sub /spl tau//, f/sub max/, I/sub cbo/, and /spl beta/ are consistent with InP based DHBTs of the same layer structure grown on a lattice-matched InP substrate.