| AVS 55th International Symposium & Exhibition | |
| Surface Science | Thursday Sessions |
| Session SS-ThP |
| Session: | Poster Session |
| Presenter: | H. Sakurai, Nagoya University, Japan |
| Authors: | H. Sakurai, Nagoya University, Japan N. Saito, Nagoya University, Japan O. Takai, Nagoya University, Japan |
| Correspondent: | Click to Email |
Ultra-water repellent film (UWR) has a water contact angle of more than 150°. The UWR property is governed by the hydrophobic groups and the geometrical structure of the surface. We have successfully fabricated UWR film by microwave plasma enhanced CVD (MPECVD) with trimethylmethoxysilane (TMMOS) as a raw material. However, the UWR film showed a poor mechanical property, because the film was composed of not a continuous film but aggregation of clusters. In order to improve the mechanical property of the UWR film, it is crucial to control the ratio of continuous film and aggregation of clusters in the film. The ratio is strongly related to the surface geometry accentuating the wettability. The large roughness makes the water repellency increase while the hardness of the structure decreases. In this study, we aimed to obtain UWR film with high hardness by tuning the surface structures and film matrix. The UWR film was deposited by MPECVD. A microwave generator (2.45GHz) was used at 250 W. Si wafer was used as substrate. TMMOS was used as a raw material, and Ar was introduced as excitation gas. The partial pressures of TMMOS and Ar were kept constant at 70Pa and 30Pa. And also, the distance between plasma and substrate was constant. The deposition time was changed 3 minutes to 30 minutes to change the surface roughness. Water contact angles on the resulting films were evaluated with a contact angle meter. Hardness of the films was measured by a nanoindentater as Vickers hardness. Surface structures of UWR films were observed by atomic force microscope (AFM). The surface roughness was evaluated by root mean square (RMS). The UWR films with smaller roughness were obtained. Even in the case, the relationship between water repellency and hardness depended on roughness. Smaller roughness would indicate the increase of continuous films. However, the Vickers hardness was not improved drastically. The film matrix was changed by the increase of oxygen and the addition of nitride and so on. The changes of film matrix have a great effect on the improvement of hardness.