Impact of hot carrier stress on RF power characteristics of MOSFETs

This paper investigates hot-carrier (HC) effects on the RF power and linearity characteristics of MOS transistors using load-pull measurement. We found that the RF power characteristics are affected by the HC stress, and the linearity of MOS transistors is clearly degraded after HC stress at constant gate voltage measurement. However, at high gate voltage bias, the HC-induced power degradation is much reduced compared with that under low gate voltage regimes. In addition, HC effects on linearity can be softened by biasing the transistor at constant drain currents. These experimental observations can be explained by the change of threshold voltage, transconductance, subthreshold swing, and mobility degradation coefficient under HC stress.