Abslracl-A quantitative model is developed for the first time, that comprehends all the unique characteristifs of NBTI degradation. Several models are critically examined to develop a reactioddiffusion based modeling framework for predicting interface state generation during NBTI stress. NBTI degradation is found to be dominated by difTusion of neutral atomic and molecular hydrogen related defects. Additionally, the presence of hydrogen gettering sites such as unsaturated grain houndaries significantly enhance NBTI degradation, whereas hydrogen sources reduce NBTI degradation. The model also suggests the possible mechanisms for saturation. The model is calibrated over a range of stress temperatures and voltages. The model captures recovery, experimental delay and frequency effects successfully.

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We describe a quantitative relationship between ID and V, driven NBTl specifications. Mobility degradation is shown to be a significant (-40%) contributor to ID degradation. We report for the first time, degradation in gate-drain capacitance (CGo) due to NBTI. The impact of this COD degradation on circuit performance is quantified for both digital and analog circuits. We find that CGD degradation has a greater impact on the analog circuit studied than the digital circuit. We demonstrate that there is an optimum operating voltage that balances NBTI degradation against transistor voltage headroom. Further, a numerical model based on the reaction-diffision theory has been developed, which is found to satisfactorily describe degradation, recovery and postrecovery response to stress.

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