| Scaling of transistor devices requires thinning of the gate dielectric to increase its capacitance. In order to decrease the leakage current, a physically thicker dielectric is necessary. The dielectric used must then have a higher dielectric constant kappa to maintain the capacitance density. We have studied two such high-kappa materials (ZrO2 and HfO2) deposited using UV ozone oxidation. In this technique, metallic precursors are deposited and then exposed to oxygen and ultraviolet light to form metal oxides. The reactivity of the metals studied results in interesting phenomena during the metal deposition and subsequent oxidation. We have observed, using high-resolution transmission electron spectroscopy and x-ray photoelectron spectroscopy, reduction and re-oxidation of the interfacial layer. Characterization of the electrical properties using MOS capacitors incorporating UV ozone processing oxides allows measurement of important physical properties. The dielectric constant of the HfO2 and ZrO2 deposited using this technique were found to be 17 and 23, respectively. The electrical thickness of the interfacial layer was found to be approximately 12 A while having a physical thickness of 15-17 A. Furthermore, electrical defects were quantified using various techniques. |
