Ubiquitous relaxation in BTI stressing—New evaluation and insights

The ubiquity of threshold voltage relaxation is demonstrated in samples with both conventional and high-k dielectrics following various stress conditions. A technique based on recording short traces of relaxation during each measurement phase of a standard measure-stress-measure sequence allows monitoring and correcting for the otherwise-unknown relaxation component. The properties of relaxation are discussed in detail for pFET with SiON dielectric subjected to NBTI stress. Based on similarities with dielectric relaxation, a physical picture and an equivalent circuit are proposed.