Effect of zirconium addition on the phase evolution of chromium zirconium nitride prepared by magnetron sputtering

Abstract

In the research reported in this contribution, chromium-zirconium nitride (CrZrN) layers were deposited on (100) silicon wafer by balance magnetron sputtering using argon and nitrogen as working and reactive gas, respectively. The coating layers were categorized into three groups according to zirconium content; low-zirconium (Low-Zr), medium-zirconium (Med-Zr) and high-zirconium (High-Zr). All layers had thicknesses in the range of 1.0-1.3 μm and the Med-Zr was the thickest sample. From the X-ray diffraction (XRD) results, zirconium could partially dissolve in chromium nitride (CrN) and formed complex nitride of chromium-zirconium [(Cr,Zr)N]. This phasic group was dominant for all samples, and the average crystallite sizes decreased with increasing zirconium fraction. In addition, the High-Zr sample had an extra broadened peak among (Cr,Zr)N peaks which could not clearly be identified by XRD. This ambiguity was eliminated by X-ray photoelectron spectroscopy (XPS). It was determined to be amorphous of zirconium oxynitride (Zr2ON2). Because of the high oxygen sensitivity of zirconium, it reacted with nitrogen and residual oxygen forming Zr2ON2. This study is among the first to examine the resulting nanoscale structure of the CrN layers incorporated with a high amount of zirconium.