InP/InGaAs double heterojunction bipolar transistors with BV_CEO = 12 V and f_max = 470 GHz

摘要

0.25 μm emitter InP/InGaAs double heterojunction bipolar transistors (DHBTs) are presented that simultaneously exhibit a high collector current density () of more than 3 mA/μm and high breakdown voltage (BV) of 12 V. The DHBTs consist of a 30 nm-thick InGaAs base, 250 nm-thick InGaAs/InAlGaAs/InP collector and 150 nm-thick -doped InP field buffer. Since the doping level of the InP field buffer is relatively high, only the InGaAs/InAlGaAs/InP collector is depleted at low . Thus, the DHBTs can provide = 173 GHz and = 470 GHz at = 3.5 mA/μm. On the other hand, at a high , both the InGaAs/InAlGaAs/InP collector and InP field buffer are depleted. Therefore, the effective depletion thickness increases, which results in a BV of 12 V. These results indicate that the use of the InP field buffer provides both high-speed performance and high BV.