Impact of Off-State Stress on SiGe-channel p-FETs in 22nm FDSOI under Large-Signal Operation

With the growing interest in high-frequency applications for CMOS, conventional DC reliability analysis might not be sufficient to tackle the reliability issues in this domain. Especially in complex modulation schemes and high-efficiency power amplifier (PA) applications, the transistors are subjected to a strong lateral field when the gate voltage lies below the threshold. Under those conditions, hot-carriers (HC) injection during off-state has become more pronounced. In this work, the impact of off-state stress on p-channel FDSOI during such conditions is analyzed and separated from normal HC degradation. A reverse-degradation with negative threshold voltage shift is observed, which is in the opposite direction than normal HC degradation. A mean to restore the device’s large-signal performance after HC degradation is also investigated.