Raman spectroscopy investigations of TiBxCyNz coatings deposited by low pressure chemical vapor deposition

TiBxCyNz coatings have been prepared applying LPCVD and characterized using SEM/EDX, XRD, and Raman micro-spectroscopy. It has been shown that first-order, defect-induced Raman spectra of good quality can be obtained from TiBxCyNz coatings, even if buried within a multilayer stack. The Raman peak assignments fit well with previous work on TiC1-xNx. Even small changes in the B:C:N ratio result in systematical shifts of the Raman peaks. With increasing nitrogen content, the acoustical phonons shift to lower frequencies. A high correlation of the Raman shifts with lattice constants derived from XRD has also been found. Additionally, intensity and FWHM of the Raman peaks also change going from carbon- to nitrogen-rich coatings. The sensitivity of the TA peak Raman shifts to changes of the investigated basic coating properties is largest for N-rich coatings. Looking at the full range of coatings the dependence of the Raman shifts is slightly nonlinear. The present work establishes Raman microscopy as a complementary non-destructive technique compared to XRD for studying coatings like TiBxCyNz. Structural, optical and chemical properties can be determined with considerably higher spatial resolution. (C) 2010 Elsevier B.V. All rights reserved.