Synthesis of Diamond-Like Carbon Coatings with Low Residual Stress and Strong Interfacial Adhesion

The diamond-like carbon (DLC) thick films, as an infrared optical window material, were synthesized by RF magnetron sputtering on substrate of double-side polished Si (100). The influence of the growth conditions on the residual stress and interfacial adhesion of DLC coatings was investigated with Raman spectroscopy, atomic force microscopy and profilometer. The results show that the high quality compact DLC coatings, with a thickness of 2. 5785 μm, a residual stress of 0. 9 GPa, a surface roughness of 0. 957 nm and a strong interfacial adhesion, were deposited under the optimized conditions:a base pressure of 2. 0×10^-7 Pa, an Ar flow-rate of 50 mL/min, an Ar-partial pressure of 7. 1×10^-3 Pa, and a sputtering power of 350 W. No film detachment in peel-off test with 3 M tape was observed, indicating an interfacial adhesion grade up to 3 B.