UC Santa Barbara

InP-In0.53Ga0.47As-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(t) and f(max) of 268 and 339 GHz were measured, respectively-both records for metamorphic DHBTs. A 70-nm SiO2 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 beta is approximate to35 and BV,CEO = 5.7 V. The collector leakage current Icbo is 90 pA at Vcb = 0.3 V. These values of f(t), f(max), I-cbo, and beta are consistent with InP based DHBTs of the same layer structure grown on a lattice-matched InP substrate.