Experimental insights on the degradation and recovery of pMOSFET under non-uniform NBTI stresses

A detail experimental study on the reliability degradation of pMOSFET under non-uniform NBTI stress was conducted. The relationship of drain bias under non-uniform NBTI stress was obtained and a turning curve was found. The non-uniform stress induced degradation can be separated into two different region based on the drain bias dependency, and the model for each region was developed and evaluated under various voltage and temperature. In addition, the conventional and enhanced NBTI stress demonstrated reverse temperature dependency. The non-uniform NBTI stress exhibited much lower recovery level, and its acceleration factor was similar to pure NBTI stress. From the temperature and voltage acceleration point of view, our results show that the non-uniform NBTI stress becomes the worst reliability corner for pMOSFETs with ultra thin gate oxynitride. The NBTI degradation with nominal drain bias was proposed to become as a device lifetime monitor for pMOSFETs.