The preparation and properties of Y2O3/AlN anti-reflection films on chemical vapor deposition diamond

Yttrium oxide (Y2O3) films have successfully been applied as anti-reflection (AR) and anti-oxidation films for diamond. For significant adhesion improvement between Y2O3 coating and diamond, aluminum nitride (AlN) as an interlayer is introduced. Y2O3 and AlN films were prepared by RF magnetron sputtering of Y2O3 ceramic target in Ar atmosphere and pure Al metal target in Ar + N2 atmosphere, respectively. The Y2O3 and AlN films were studied by X-ray diffraction, X-ray photoelectron spectroscopy, Atomic force microscopy and Spectroscopic ellipsometry. Adherent Y2O3/AlN films on high optical quality chemical vapor deposition diamond with optimum thicknesses for infrared transmission enhancement in 8–10 μm were obtained by a Fourier transform infrared spectrometer. More than 28% increase in maximum transmission was observed for Y2O3/AlN//Diamond//AlN/Y2O3. Comparing between the designed and experimental AR effects for Y2O3/AlN film in 8–10 μm wavebands, experimental average AR effects are smaller for the absorption and scattering loss. AR effects for the Y2O3/AlN films on CVD diamond are proved to be excellent.