Statistical observations of NBTI-induced threshold voltage shifts on small channel-area devices

Performance variability of miniaturized devices has become a major obstacle for designing electronic systems. Temporal degradation of threshold voltages and its variation are going to be an additional concerns to ensure their reliability. In this paper, based on measurement results on large number of devices, we present statistical properties of device degradation and recovery. The measurement data is obtained by using a device-array circuit suitable for efficiently collect statistical data on degradations and recoveries of very small channel-area devices. Stair-like change of threshold voltages found in our measurement suggests that charge trapping and emission may play a key role in the device degradation process.