Review of bias-temperature instabilities at the III-N/dielectric interface

Abstract

Two particular defects are commonly discussed at the III-N interface: the required donor states, known to exist from the formation of the two-dimensional electron gas (2DEG) below a hetero-barrier, and defect states at the interface or within the dielectric layer. It appears that the latter ones are responsible for the ongoing challenge to find a low-defect gate dielectric to reduce positive bias temperature instabilities (PBTI). This raises the question, why the natively given donor states behave almost like fixed charges. We review the known and verified characteristics for both defect types and the link between them. Moreover, we define a lifetime criterion for power switching applications to compare PBTI effects related to III-N interfaces.