SiCxHy-based hydrophobic thin films with good chemical and mechanical properties synthesized by PECVD at various substrate temperatures

• Hydrophobic films were synthesized by simple PECVD.
• The contact angles of the samples were 105 ± 5°.
• The hardness of the samples was increased to 6H.
• The chemical resist test showed that the samples have strong resistance.
• This explains that high pencil hardness and strong chemical resistance.

This work investigates on chemical and mechanical resistance of hydrophobic films; prepared using radio frequency (RF) plasma enhanced chemical vapor deposition (PECVD) method, by varying substrate temperature. For this work, Hexamethyldisilane (HMDS) is used as the precursor, with hydrogen gas as the reactive agent. The surface energy and surface morphology are studied by measuring water contact angle (WCA) and atomic force microscopy (AFM), respectively. Measurement reveals that WCA does not change much and acquires the value in between 105 and 110°. FT–IR analysis shows that the films are well-covered with “–CHx” groups, which can provide the hydrophobicity. The pencil hardness test of the deposited films at higher substrate temperature (>160 °C), have shown a high stability up to 6H. Also, the films show good chemical resistance against boiling salt water and cosmetics in the chemical reliability test due to their much denser structure with reduced defects. Additionally, XPS analysis shows that there is the shift in the peak position of the C–C bond to lower binding energy that is attributed to a highly cross-linked carbon structure formation in the film. The films are chemically inert and have shown good adhesion and durability.