In-Depth Understanding of Nitridation-Induced Endurance Enhancement in FeFETs: Defect Properties and Dynamics Characterized by Nonradiative Multi-Phonon Model

Abstract

In this work, by analyzing the properties and dynamics of defects in detail, the role of nitrogen in improving the endurance of ferroelectric field-effect transistors (FeFETs) is clarified. First, the properties of defects (trap energy level ${E}_{\text {T}}$ , relaxation energy ${E}_{\text {R}}$ , and defect density ${N}_{\text {T}}$ ) of FeFETs with SiO2/SiON are investigated in depth through nonradiative multi-phonon (NMP) model. The nitridation process can significantly decrease the population and density of defects in the interfacial layer. Moreover, by comparing the defect dynamics in the interfacial and ferroelectric layers of nitridation/nonnitridation devices during cycling, we find that the nitridation process reduces the charge transition rate of defects and the number of memory window (MW) degradation pathways. The underlying mechanism of the nitridation process that can explain the increase in endurance is revealed. These findings enhance the understanding of reliability concerns in FeFET devices, paving the way for improving the performance of FeFETs.