Product NBTI Distribution and Voltage Dependence - impact of relaxation and droops

The impact of relaxation and droops in determining the voltage dependence of NBTI during product stressing is discussed. This has implications on the Fmax and Vmin guardbands extrapolated from product stress to use conditions. Voltage dependence for the shift of the 3sigma tail bits in both new and old technology nodes are compared to illustrate the importance of relaxation and droops.