Design of AlInAs/GaAsSb/InGaAsSb Double Heterojunction Bipolar Transistors for The Unit Current Gain Cutoff Frequency of 850GHz

In this work, the design of double heterojunction bipolar transistors (DHBTs) is to improve the unit current gain cutoff frequency (fT). We proposed using a compositionally graded emitter and adding a ledge layer between the base and the emitter to enhance fT. These results exhibit the high fT of these DHBTs.