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Microwave sheath-voltage combination plasma (MVP) is high-density plasma generated in the substrate vicinity. Plasma Chemical vaper deposition (CVD) with MVP enables deposit of a-C:H:Si film at much higher deposition rates than with conventional plasma CVD employing DC and RF plasmas. Nevertheless, the friction property of a-C:H:Si films deposited using MVP, where deposition rates are typically higher than 100 μm/h, have not been elucidated. Therefore, for this study, ball-on-disc friction tests of a-C:H:Si films deposited by MVP were conducted, where a steel ball (SUJ2, JIS) is slid against a coated steel disk (S25C or SCM415, JIS) at a normal load of 9.8 N and sliding speed of 0.157 m/s under dry conditions in ambient air. The MVP-synthesized a-C:H:Si films with Si contents of 5.5-19.6 at% showed a friction coefficient of 0.025-0.12, indicating a friction coefficient of around 0.05, which has been reported often for conventional a-C:H:Si films, is possible by a-C:H:Si films deposited by MVP. A conventional a-C:H:Si film with silicon content of 7.2 at%, which was deposited using a commercial DC plasma CVD for comparison, showed a friction coefficient of 0.12 from the same test. For these films, the friction coefficient decreased with the hydrogen content in the film detected using Rutherford backscattering spectroscopy (RBS)-Elastic recoil detection analysis (ERDA). This tendency was not reported for conventional a-C:H:Si films. Compared to the hydrogen content, carbon and silicon contents in the film were detected using RBS-ERDA. The oxygen detected at the film surface using X-ray photoelectron spectroscopy (XPS) did not clearly correlate with the friction coefficient. Additionally, results show that the specific wear rate of a-C:H:Si film increases monotonically with the film's Si content. This result is similar to a tendency reported already for conventional a-C:H:Si films.

Investigation of the low temperature synthesis of carbon nitride was carried out by microwave plasma CVD. Carbon nitride was synthesized using an improved microwave plasma CVD apparatus. Si was used as the substrate. A mixture of CH4 and N2 gas was used as a reaction gas. Synthesis pressure was varied from 1.1 to 4.0 kPa, microwave power was varied from 400 to 800 W. Faceted particles were obtained at a microwave power of 800 W and a substrate temperature of 880 K. Faceted particles were obtained at various synthesis pressures and a substrate temperature of as low as 740 K. Also, β-Si3N4 and α-C3N4 peaks were observed in the X-ray diffraction (XRD) pattern. As a result of studies of the low-temperature synthesis of carbon nitride by microwave plasma CVD, the morphology of deposits was found to depend on substrate temperature, and faceted particles were obtained at a substrate temperature as low as 740 K.

Ippei Tanaka a),b), * and Yukihiro Sakamoto c) Graphitic carbon nitride (g-C 3 N 4) is one of the metal-free photocatalyst materials. Investigation was carried out on the synthesis of g-C 3 N 4 films by thermal CVD using melamine. A thermal chemical vapor deposition apparatus of the hot-wall type was used for g-C 3 N 4 film deposition on a Si substrate. Melamine was used as the feedstock. The heating temperatures of the substrate were varied from 773 to 973 K. The g-C 3 N 4 films were analyzed by SEM, XRD, Raman spectroscopy, FT-IR, and XPS. The thickness of the deposited films at a heating temperature of 873 K was from 0.6 to 1.0 µm. A peak of g-C 3 N 4 was observed in the XRD patterns at heating temperatures of 873 and 973 K. From FT-IR and XPS, C and N bonds were observed at a heating temperature of 873 K. We concluded that g-C 3 N 4 films of thickness 0.6 to 1.0 µm were obtained at a heating temperature of 873 K.