Effect of RF power on properties of diamond-like carbon films

The diamond phase fraction, optical constant and hardness of diamond-like carbon thin films deposited at different radio frequency powers by radio frequency plasma chemical vapor deposition have been investigated. The diamond phase fraction, optical constant and hardness of single-layered thin films at different radio frequency powers have been measured by using Raman spectroscopy, spectroscopic ellipsometer and micro-sclerometer, respectively. With the increase of radio frequency power, the fraction of diamond phase decreases and the growth rate of films increases, especially when the power is above 910 W. The refractive index of films decreases in the range of 660-860 W and 910-960 W and increases between 860 W and 910 W. The hardness increases and then decreases between 660 W and 960 W with its maximum at 860 W.