| Summary: | 博士 === 大同大學 === 材料工程研究所 === 89 === In this thesis research, synthesis and characterization of a number of technologically and scientifically interesting Aluminum oxide films and ultrathin carbon nitride coatings was investigated. Magnetron sputtering was utilized for film deposition and the films were characterization by a wide variety of techniques to obtain information on hardness, microstructure, composition, surface morphology, corrosion performance, and wear rate.
Aluminum oxide films were grown by reactive magnetron sputtering. In order to maintain a stable deposition process and high deposition rate, a pulsed dc bias was applied to the aluminum target and the substrate. An external solenoid was used to form a magnetic trap between the target and the substrate. The influence of substrate temperature, substrate bias and the magnetic trap on film growth and properties was studied by different surface and thin-film analysis techniques and electrical measurements. Normally, amorphous alumina films were produced. However, under optimum process conditions, crystalline alumina films can be obtained at temperatures as low as 250 oC, with a hardness ~ 20 GPa and excellent electrical insulating properties.
Effects of substrate bias and magnetic trap on film properties were investigated. Under optimum conditions, crystalline alumina films were obtained at substrate temperatures ~340 oC and refractive index 1.65-1.85 in the visible region. Friction and wear properties of crystalline and amorphous alumina thin films were compared.
Ultrathin carbon nitride coatings were grown for use as protective overcoats in computer hard drives. In order to obtain an area storage density of 100 Gbits/in2, the overcoat thickness is required to be within 2 nm, and the coating needs to be wear-resistant, smooth and defect-free. These requirements were satisfied for films grown under an optimum substrate bias where the energy distribution of the incoming ions was minimized and the substrate and target power supplies were pulsed at high frequency.
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