关键词: 硅锗异质结晶体管, 电流加速, 可靠性, 热载流子效应

Abstract:

The hot carrier effect （HCE） of SiGe heterojunction bipolar transistor （HBT） is generally rneasured using the voltage-accelerated degradation method at high reverse emitter-base （EB） voltages with open-circuit col- lector （OCSAM）. However, when OCSAM is employed, the failure mechanism of SiGe HBT at high voltages is dif- ferent from that at low voltages, and the time cost is high. In order to solve these problems, the HCE reliability evaluation of SiGe HBT is carried out using the current-accelerated stress method at low reverse EB voltages and high stress current achieved by forward-biasing the collector-base （CB） junction （FCSAM）. The variation of elec- trical characteristics before and after the application of stress is investigated and the degradation mechanism of elec- trical characteristics is analyzed. The results show that, with the increase of applying time of stress, the current gain gradually degrades. As compared with the conventional voltage-accelerated method OCSAM, FCSAM signifi- cantly saves the test time and can effectively predict the long-term reliability of SiGe HBT.

Key words: SiGe heterojunction bipolar transistor, current acceleration, reliability, hot carrier effect