Growth and characterization of Cr2N/CrN multilayer coatings

A series of monolithic and multilayer coatings of chromium nitride with various compositions and architectures were deposited at low temperatures (<200°C) on silicon substrates using ion-assisted reactive magnetron sputtering. All coatings had a total thickness in the 1.5±0.3 μm range. The multilayer coatings were designed such that their period and CrN fraction varied in the range 30–150 nm and 0.50–0.93, respectively. Real-time in situ ellipsometry was used to monitor and control the deposition process. The deposited coatings were characterized post-deposition using X-ray diffraction (XRD), Rutherford backscattering (RBS), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). The primary chromium nitride phases (Cr2N and CrN) in the films were identified using XRD. The chemical composition of selected samples was determined from RBS and XPS measurements. The phase composition of the deposited layers was deduced from the analysis of the SE data. The mechanical properties of the coatings were evaluated using a nanoindenter. The measured hardness values were in excess of 20 GPa. The results of the different characterization and testing techniques were correlated and follow-up work on this project suggested.