Optimization of the Deposition Parameters of DLC Coatings with the IC-PECVD Method

Abstract

Amorphous carbon film, also known as diamond-like carbon (DLC) film, is a promising material for tribological application. It is noted that properties relevant to tribological application change significantly depending on the method of preparation of these films. These properties are also altered by the composition of the films. In view of this, the purpose of the present study was to determine the optimal values of selected deposition parameters of hydrogenated DLC films on high-speed steel tool substrates with the inductively coupled plasma enhanced chemical vapor deposition (IC-PECVD) method. To optimize the deposition parameters for hydrogenated DLC films, Taguchi's method was used. Deposition parameters (bias voltage, bias frequency, deposition pressure, and gas composition) were optimized with consideration to hardness of the film. Based on the experimental results, the optimal parameter setting are −50 V, 500 Hz, 4 µbar, and 90:10 for achieving maximum value of hardness. It was found that bias voltage has greater influence on hardness. At the optimum conditions, the conformance run resulted in a hardness value of 1580 KHN. Atomic force microscopy images showed that the DLC films are smooth with an average roughness (Ra) of 1.24 nm on silicon substrate.

Keywords:

• Atomic force microscopy
• diamond-like carbon film
• inductively coupled plasma enhanced chemical vapor deposition
• Raman spectroscopy
• Taguchi's method