Synthesis ZrON Films with Raman-Enhancement Properties Using Microwave Plasma

Abstract

The paper investigates the characteristics of the formation and morphology of microstructured zirconium oxynitride (ZrON) films, taking into account structural polymorphism during the impact of atmospheric-pressure microwave nitrogen plasma with the influx of active oxygen from the surrounding atmosphere. Optical, hydrophobic, Raman-active properties of ZrON films have been studied. X-ray diffractometry (XRD), scanning electron microscopy (SEM), ellipsometry method, and Raman spectroscopy, and moisture-resistance properties are used as analytical research methods. It is shown that during the short-term impact of microwave plasma, a morphologically heterogeneous ZrON film can be formed with a set of microhills with a uniform phase composition along the surface. The phase composition of the ZrON surface corresponds to the monoclinic structure of ZrO2. In the volume of the film, a predominantly tetragonal structure of ZrO2 is observed, as well as inclusions of the monoclinic structure of ZrO2. A mechanism for the formation of a ZrON film, taking into account polymorphism and phase transitions, is proposed. The optical properties of ZrON films are determined by both the dielectric phase of ZrO2 and the inclusions of the high-conductivity phase of ZrN. A combination of such factors as the developed microrelief and monoclinic surface structure, as well as nitride phase inclusions, enhance the hydrophobic properties of the ZrON film surface. It is shown that the surface hydrophobicity and resonant effects on ZrN inclusions allow for the enhancement of the Raman spectrum intensity due to the high concentration of analyte molecules in the scanning area.