Preparation of ZrO2 ultrathin films as gate dielectrics by limited reaction sputtering-On growth delay time at initial growth stage

ZrO2 thin films were produced by limited reaction sputtering process varying the deposition parameters. An interesting growth phenomenon was observed in the initial growth stage of amorphous samples, appearing to suppress film growth for the first several minutes. The structures of such ultrathin ZrO2 films were investigated by high-resolution Rutherford backscattering (HR-RBS) and X-ray photoelectron spectroscopy (XPS). The results suggest that the existence of interfacial suboxides due to the adsorption-induced surface reaction and diffusion-induced internal reaction, lead to the deteriorated interfacial performance. The mechanism and effects of the growth delay time on the interfacial characteristics are discussed in detail.