High performance monolithic InP HBT-HEMT integration

In this paper, we report the successful integration of high performance 0.5¿m heterojunction bipolar transistors (HBTs) and 35nm high electron mobility transistors (HEMT) on an indium phosphide (InP) substrate. Both transistors demonstrate power gain cutoff frequencies (fmax) in excess of 300GHz, a ~2x improvement over previously reported results from integrated InP devices. The device epitaxy is grown in a single growth with the HEMT beneath the HBT sub-collector. Optimization of the device epitaxy and the HEMT lithography processes allow for HEMT-to-HBT separation of <10¿m.