Atomic Modeling of nitrogen neighboring effect on negative bias temperature instability of pMOSFETs

In this letter, further evidence from atomic modeling is presented to support the proposed nitrogen neighboring effect, which explains the two distinct regimes in the dependence of negative bias temperature instability (NBTI) degradation on the interfacial nitrogen concentration N-int (i.e., the dependence for N-int > 8 at. % is stronger than that for N-int < 8at. %). Our calculations clearly show that the enhancement of the NBTI degradation by nitrogen becomes stronger when the number of neighboring N atom increases with increasing the N-int. In addition, the role of nitrogen in NBTI is also examined in terms of the electronegativity and atomic charge distribution. This letter clearly suggests that the N neighboring effect is detrimental to future generations of MOS devices that require higher N-int for the gate oxide.