Interface structures generated by negative-bias temperature instability in Si/SiO2 and Si/SiOxNy interfaces

We used a density functional method to investigate the mechanism of negative-bias temperature instability (NBTI) and resultant structural changes of Si/SiO2 and Si/SiOxNy interfaces. The reaction energies for the water- and hydrogen-originated instabilities of several interface defects show that water-originated reactions of oxygen and nitrogen vacancies occur most easily. The larger instability of the Si/SiOxNy interface, compared with the Si/SiO2 interface, can be understood in terms of the difference in reaction energies. According to the calculated nitrogen 1s core-level shifts of the nitrogen atoms at the Si/SiOxNy interface, it is possible to identify a NBTI-generated structure at the Si/SiOxNy interface by x-ray photoelectron spectroscopy. (C) 2002 American Institute of Physics.