High speed (207 GHz f/sub /spl tau//), low thermal resistance, high current density metamorphic InP/InGaAs/InP DHBTs grown on a GaAs substrate

InP/In/sub 0.53/Ga/sub 0.47/As/InP double heterojunction bipolar transistors (HBTs) were grown on GaAs substrates. InP layer was employed as a metamorphic buffer layer because of its high thermal conductivity. A 140 GHz power-gain cutoff frequency f/sub max/ and a 207 GHz current-gain cutoff frequency f/sub /spl tau// were obtained, presently the highest reported values for metamorphic HBTs. The breakdown voltage BV/sub CEO/ was 6 V while the DC current gain /spl beta/ was 76.