Diamond-like carbon (DLC) films, which are amorphous carbon films, have been used as hard-coating films for protecting the surface of mechanical parts. Nitrogen-containing DLC (N-DLC) films are expected as conductive hard-coating materials. N-DLC films are expected in applications such as protective films for contact pins, which are used in the electrical check process of integrated circuit chips. In this study, N-DLC films are prepared using the T-shaped filtered arc deposition (T-FAD) method, and film properties are investigated. Film hardness and film density decreased when the N content increased in the films because the number of graphite structures in the DLC film increased as the N content increased. These trends are similar to the results of a previous study. The electrical resistivity of N-DLC films changed from 0.26 to 8.8 Ω cm with a change in the nanoindentation hardness from 17 to 27 GPa. The N-DLC films fabricated by the T-FAD method showed high mechanical hardness and low electrical resistivity.

We have investigated the microfabrication of diamond films on silicon substrates using the localized electron beam (EB) chemical vapour deposition (CVD) method with a hydrogen (H 2) and methane (CH 4) mixed gas source. Micro-Raman spectra at 1, 3 and 5% CH 4 concentrations for the accelerating voltage of 10 kV have indicated the presence of a diamond (sp 3 bonding) peak at 1333 cm −1 , a graphite (sp 2 bonding) peak at 1580 cm −1 and a diamond peak, and an amorphous carbon peak at 1360 cm −1 and graphite peak, respectively; those at 7 and 10% concentrations have indicated broad amorphous carbon peaks around 1500 and 1300 cm −1. We have found that the films consist of a mixture of sp 3 and sp 2 bonded structures. The film quality (sp 3) content decreases with increasing CH 4 concentration. Consequently, the localized EB CVD diamond films have been fabricated under the following deposition conditions: an accelerating voltage of 10 kV and a CH 4 concentration of 1%. The EB was scanned in areas of 2 × 10 µm 2 rectangle and 1 × 1 µm 2 square on a silicon substrate. The two-dimensional cross-sectional profiles (X-Z axis) of the resulting micro-rectangular diamond patterns were very similar to those of the resulting micro-square diamond patterns. The deposited thickness of the resulting micro-rectangular and square diamond patterns increased linearly with increasing EB irradiation time up to a limit of 10 h. The deposition rate was approximately 0.1 µm h −1 in both cases. The full width at half maximum (FWHM) of the cross-sectional profiles, having the triangular form of the resulting micro-rectangular and square diamond patterns, first increased with increasing EB irradiation time and reached a maximum width at an EB irradiation time of 4 and 6 h, respectively and then decreased gradually with a further increase of the EB irradiation time. The deposited thickness and FWHM of the resulting micro-rectangular and square diamond patterns for a 10 h EB irradiation time were 1.1, 0.98 µm and 3.6, 3.3 µm, respectively.

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The etching characteristics of CVD (chemical vapour deposition) diamond films processed with an ECR (electron cyclotron resonance) oxygen plasma are investigated. The etching rate increases linearly with increasing microwave power in the range from 100 to 300 W. For any value of microwave power, the etching rate first increases with increasing gas flow rate, reaches a maximum rate at a gas flow rate of 3 sccm (standard cc min-1), and then decreases gradually with further increase in the gas flow rate. The etching rate increases linearly with increasing negative bias voltage in the range from 0 to -600 V. The etching rate for 100 and 300 W of microwave power and a negative bias of -600 V is 17 and three times greater, respectively, than that for 0 V bias. The surface roughness increases with increasing microwave power in the range from 0 to 300 W. The surface roughness before etching is eight times greater than that obtained after plasma etching with 300 W of microwave power. The Raman spectrum of a CVD diamond film after oxygen plasma etching for 1 h shows not only a diamond (sp3 bonding) peak at 1333 cm-1, but also a broad non-diamond (sp2 bonding) peak around 1500 cm-1. However, as the etching time increases, the broad non-diamond peak around 1500 cm-1 disappears.