The structure and optical properties of C doped BN thin films deposited by RF reactive magnetron sputtering

The C doped BN thin films were assembled on Si (1 1 1) and quartz substrates utilizing BN target by magnetron sputtering with CH4 as reactive gas and Ar as working gas. Atomic force microscopy (AFM), Raman, X-ray photoelectron spectroscopy (XPS) and UV-visible (UV-vis) spectrophotometer are conducted to test and analyze the structures and optical properties of the thin films. The films deposited at various CH4 flow possess compact and uniform surface. All thin films are mainly composed of B-N, B-C and C-N chemical bonds. Raman spectra show that ID/IG in the thin films increases with the growing of gas flow rate ratio (R = F-CH4/(F-CH4+F-Ar)). Moreover, the optical band gap (E-g) of the C doped BN thin films is ranging from 4.04 to 5.16 eV. In addition, the E-g value of the C doped BN thin films decreased with the growing of R. This was owing to the increase of carbon content since this contributed to the increase of pi bonding originating from C=C bond.