Phase Space Based NBTI Model

A phase space based NBTI model that relies upon the well-known reaction-diffusion model is introduced. Temporal shift in threshold voltage and a new parameter called “healability” are used to characterize the state of the NBTI effect. The NBTI degradation is then simulated as a trace of the interpolated characterization parameters. Thereby, healability is crucial for the success of the model. The phase space based model is well suitable in performance oriented use cases, since a small deterioration of the simulation results comes with a vastly improved simulation speed. The additional phase space dimensions of temperature and supply voltage in combination with the conversion between duty cycle and supply voltage permit a performance efficient way to simulate NBTI degradation for complete circuits without disregarding power gating, temperature profiles and the IR drop.