Re-examination of Deuterium Effect on Negative Bias Temperature Instability in Ultra-thin Gate Oxides

In this work, the effect of deuterium on negative bias temperature instability (NBTI) was investigated using p+-gate and n+ -gate/pMOSFETs. As a result, it was found that the elimination of interface-trap generation by deuterium incorporation is observed in the case of n+-gate/pMOSFETs, while no isotope effect is observed in p+-gate/pMOSFETs. The correlation between energy of injected carrier and interface trap generation was investigated based on the impact ionization probability. In the case of p+-gate/pMOSFETs, the interaction between Si-H bonds and holes in the inversion layer seems to be responsible for hydrogen release from SiO2/Si interface. On the other hand, in the case of n+-gate/pMOSFETs, injecting energetic electrons from gate electrodes break Si-H bonds. Namely, it can be concluded that two processes of Si-H bond breaking relate to interface trap generation under NBT stress