Quantum Chemical Molecular Dynamics Study of Degradation Mechanism of Interface Integrity between a HfO2 Thin Film and a Metal Gate Electrode

Control of the interfacial crystallographic structure between a dielectric film and a gate electrode is one of the most critical issues for assuring the high performance and the reliability of a stacked MOS structure using high-k dielectric thin films. In this study, quantum chemical molecular dynamics was applied to explicate the mechanism of degradation of interfacial integrity of the gate stack systems which is caused by point defects. We found that point defects such as oxygen and carbon interstitials deteriorate the electronic quality of a hafnium dioxide film and the W/HfO₂ interface structure. The estimated results were confirmed by experiments using synchrotron-radiation photoemission spectroscopy.