Electric-field dependence of negative-bias temperature instability

Abstract

To investigate the origin of the electric-field dependence of negative-bias temperature instability (NBTI), we calculated the change in the activation energies of the dissociation reaction of a Si–H bond caused by an electric field. The calculated activation energies show that the change is too small to explain previously reported experimental electric-field dependence. On the other hand, a hole generated by the electric field in the silicon/gate-dielectric interface reduces the activation energy much more. We propose a NBTI mechanism based on the calculated activation energies. This mechanism can be applied to estimate NBTI lifetime over a wide range of electric fields.

Transfer of a Positive Fixed Charge between Si and SiO2 in a Si/SiO2 Interface with Hydrogen Migration

“…12, a modified form of the reverse reaction of Eq. 11, as a positive [12] charge transfer reaction in the present study. This reaction causes decrease of interface traps with hydrogen passivation of the traps.…”

“…In the present study, we investigated the reaction without electric field applied because of difficulty in calculation of reliable total energy of a charged molecule under an electric field. We anticipated that the effect of electric field should be small from our results for electrically neutral molecules (12), but improvement of calculation method is necessary to obtain a decisive conclusion about effect of an electric field on NBTI.…”

“…In addition, electric-field dependence of dissociation of a Si-H bond also has to be considered. In our previous paper (12), we proposed a new formula for electric-field dependence of NBTI based on the following calculated results: diffusive charged species in NBTI is a positive charge (a hole), not a proton (11); hydrogen migration has no electric-field dependence.…”

“…In the present study, we traced a transfer reaction of a positive charge from a Si substrate to a SiO 2 film at the Si/SiO 2 interface with hydrogen migration using a molecular orbital calculation. Before describing the details of the present study, we summarize the results of our previous studies about the role of hydrogen in NBTI (11,12) from the viewpoint of the present paper.…”

PECVD-AlOx/SiNx Passivation Stacks on Silicon: Effective Charge Dynamics and Interface Defect State Spectroscopy

“…This degradation of chemical passivation can be attributed to a dissociation of the atomic bonds (e.g. Si-H or Si-O bonds) [44][45][46].…”