Composition analysis of boron carbide coatings prepared by reactive sputtering with nitrogen

Boron carbide coatings were prepared by reactive sputtering with nitrogen and investigated for their optical properties. Different ratios of N2/Ar (4%, 8%, and 15% nitrogen ratio) mixture gas was chosen as the sputtering gas. The atomic concentration distribution and elemental chemical states of coatings were characterized by X-ray photoelectron spectroscopy measurements. The B/C ratio was 3.7:1 and the nitrogen content was 18 at.% in the coating, which was sputtered with 4% N2 mixture gas. And the nitrogen content was increased as the ratio of N2 increases in mixture gas. In the nitridated B4C coatings, the boron mainly existed as the formation of BN and B4C compounds. The theoretical reflectivity was performed, and the increase of nitrogen content would reduce the reflectivity in the soft X-ray, especially in the vicinity of 410 eV.