Effects of fluorine plasma treatment on the electronic structure of plasma-enhanced atomic layer deposition HfO₂

We investigated the effects of fluorine treatments on the electrical properties and electronic structures of plasma-enhanced atomic layer deposition HfO₂ gate oxides, depending on the treatment process. Pre- and postoxide-deposition fluorine treatments were carried out using CF₄ plasma. Improved dielectric properties were achieved by predeposition treatment, while degradation of electrical properties was observed for postdeposition treatment. Based on the electronic structure analysis using X-ray photoemission spectroscopy and near-edge X-ray absorption fine structures, we found that the enhanced dielectric properties of the pretreated HfO₂ are induced by the defect passivation and conduction-band offset increase.