Coupled Approach for Reliability Study of Fully Self Aligned SiGe: C 250GHz HBTs

High performance bipolar transistors were investigated under both reverse and forward stress conditions. Although classical hot-carrier induced degradation has been shown in reverse mode, the results obtained under forward conditions were not in line with those reported for previous device generation. Indeed, the coupled approach using low frequency noise spectra measurements and reliability studies show a relaxation of the pre-existing and/or created defects during stress. Moreover, coexistence of both classical Shockley-Read-Hall recombination and unusual trap-assisted tunnelling is clearly demonstrated and confirmed by TCAD simulations.