Modeling and Characterization of Negative Bias Temperature Instability in p-Channel MOSFETs

Abstract

Negative bias temperature instability (NBTI) of nitrided gate oxides prepared with different nitridation process is characterized and the NBTI results can be well described by an analytical reaction-dispersive-diffusion model in the diffusion-limited regime. The activation energies are re- calculated by eliminating the non-Arrhenius part, and it confirms that both the interfacial nitrogen concentration and the nitrogen depth profile in the nitrided oxides play important roles in the nitrogen-enhanced NBTI. Furthermore, first-principles calculations are carried out to examine the effects of nitrogen as either the reaction site or the neighboring atoms at the interface. Lower reaction energies due to the incorporation of nitrogen suggest that nitrogen is a more effective hydrogen-originated hole trapping center than oxygen, and hence enhances NBTI. It is also found that hydrogen-originated hole trapping at vacancy defect has the strongest dependence on the nitrogen neighboring effect. Moreover, the role of nitrogen in NBTI is also investigated in terms of its influence on the electro-negativity and atomic charge distribution.