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.

No abstract

No abstract

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.

The role of dimerization of atomic hydrogen to give molecular hydrogen in determining negative bias temperature instability (NBTI) kinetics is explored analytically. The time dependency of NBTI involving molecular hydrogen was found to obey a power law with a slope of 1∕6, as opposed to the 1∕4 slope derived for a reaction involving atomic hydrogen. The implications of this dimerization reaction for voltage and temperature acceleration are also discussed. Simulation results validating these predictions are also described. The higher slopes typically reported for NBTI are shown to be an artifact of measurement, and experimental data supporting this lower time dependency is shown.