Reduction of RTS Noise in Small-Area MOSFETs Under Switched Bias Conditions and Forward Substrate Bias

Low-frequency noise in small-area MOSFETs is dominated by random telegraph signal noise associated to the capture and emission of charge carriers by a single trap located in the gate dielectric. RTS noise degrades the performance of analog, digital, and memory circuits. In this paper, we present measurements and simulations of RTS noise in small-area MOSFETs under constant bias and switched gate bias conditions in order to investigate the impact of substrate bias on RTS noise. Our results show that a strong reduction of RTS noise under switching bias conditions is obtained when a forward substrate bias is applied during the device off-state. Measurement of RTS mean emission and capture times proves that such a reduction of RTS noise is caused by a significant decrease in emission time constant occurring when a low gate voltage and a positive substrate voltage are simultaneously applied in the frame of a switching bias scheme.