Study Of The Effect Of The Temperature And The Magnetic Field On Nbti In The Mosfet Devices

Résumé: Negative Bias Temperature Instability (NBTI) is a serious degradation mechanism in nanoscale devices and circuits. It impacts mainly P-channel devices by generating traps at the Si/SiO2 interface as well as in the oxide bulk. These generated traps cause the degradation of the most important transistor parameters such as threshold voltage, saturation current and channel mobility. Since the improvement of devices and circuit performance is the main target in nanotechnology, investigating the physics of the NBTI and its modelling is essential and highly useful. In this thesis, the study of NBTI degradation for pure-SiO2 is undertaken and it shows that despite of many models that have been developed, none of them gets the consensus especially on the microscopic origin of fast and permanent components. The proposed models in the literature can be split into two big categories: Hydrogen based models or Reaction-Diffusion (RD) models and hole trapping detrapping models also called Energy Well (EW) models. Some authors attempts to propose models that combine both hydrogen and hole contribution, but they diverge on which of them is behind the permanent part or the fast recovery one. Although NBTI is extensively studied and several models have been proposed in the past, its physical mechanism has remained a field of great debate. In this thesis, a new physical based model, which extends the two-stage model to account the hydrogen diffusion in the oxide, is proposed. In our model holes in correlation with hydrogens in the oxide are responsible of NBTI and in contrast to any other proposed model both hole and hydrogen related defects contribute to fast and long term recovery and the two components are correlated at stress uncorrelated in recovery period. The validity of the model equations is checked using COMSOL Multiphysics simulator

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