The conduction process of grain and grain boundary in the semiconductive zirconium oxynitride thin film

摘要

Semiconductive zirconium oxynitride (ZrOxNy) thin film was deposited on a sapphire substrate by reactive magnetron sputtering, and micro temperature sensors based on the film were fabricated by a microelectromechanical system (MEMS) micromachining process. The detailed structure of the ZrOxNy thin film was examined using x-ray diffractometer (XRD), scanning electron microscopy (SEM), field emission transmission electron microscope (FE-TEM), and the depth profiles of different elements and zirconium compounds in nanoscale were further researched by depth x-ray photoelectron spectroscopy (XPS). The conduction process of the whole film, the grain and the grain boundary of ZrOxNy thin film were investigated with temperature dependent AC impedance spectroscopy. It is found that the conductivity of the ZrOxNy film is dominated by thermal activation and Mott variable range hopping (VRH) in the temperature range of 300 K-75 K and 75 K-10 K, respectively. The conduction process of the grain and grain boundary follow thermal activation model in relatively high temperature range. With the reduction of temperature the conduction process of the grain boundary obeys Mott VRH, while concerning the conduction process for the grain, the nearest-neighbor hopping (NNH) should also be taken into account in addition to Mott VRH.