Hybrid Deposition Method Research Articles

Effect of Substrate Bias on Structure and Properties of W incorporated Diamond-like Carbon Films

AbstractW incorporated diamond-like carbon (W-DLC) films were deposited on silicon (100) wafers by a hybrid deposition method combining ion beam deposition of carbon with DC magnetron sputtering of tungsten. During the films deposition, a wide range of negative bias voltage from 0 to -600 V was applied. W concentration in the film could be controlled by varying the Ar/C6H6 ratio in the supplying gas. In the present experimental condition, WC1−x nano-sized particles were not observed in the amorphous carbon matrix. Regardless of the W concentration in the film, it was found that the G-peak position of the Raman spectra had a lowest value at a bias voltage of - 200 V, which represents the highest sp3 bond fraction in the film. The highest residual stress, hardness and Young's modulus were also observed when the bias voltage was -200 V. This result shows that the mechanical properties of W-DLC films were mainly dependent on the atomic bond structure of carbon. On the other hand, the electrical resistivity significantly decreased by the W incorporation.

Hybrid deposition of sputtered and evaporated multilayer thin films

Si:H/CaF 2 and Si:H/HfF4 high reflectors with as many as 27 layers were deposited by a hybrid process that combined reactive magnetron sputtering and electron beam evaporation. The ultimate goal of this work was to deposit interference filters with low near-infrared (NIR) and LWIR absorption for use in thermophotovoltaic systems. The high index Si:H layers were deposited by reactive magnetron sputtering in mixtures of Ar+H2. Electron beam evaporation was the preferred deposition method for the CaF2 layers. The multilayer hybrid coatings were deposited in the same chamber by sequentially rotating the substrate over the Si sputtering target and the CaF2 evaporation source. The deposition rate of the evaporated CaF2 was 18.3 Å/s, compared to 0.42 Å/s for sputtered CaF2. The deposition rate of the Si:H layers was 1 Å/s. The refractive index of the SiH at NIR wavelengths was 3.45, with extinction coefficient <0.001. The refractive index of the CaF2 in the same wavelength range was 1.34, with an extinction coefficient <0.0001. The refractive index of HfF4 was 1.56 in the same wavelength range, with a comparable extinction coefficient. The resulting multilayer coatings had lower physisorbed water than those with sputtered CaF2 layers. The optical performance of the 9- and 27-layer all-sputtered and hybrid coatings was similar. The major advantage of the hybrid process was in deposition times. The deposition rate of the magnetron sputtered fluoride films was at least an order of magnitude lower than that of the e-beam evaporated films. The times required to deposit a quarter-wave (QW) optical thickness (3.2 μm) for hybrid (Si:H/HfF4) and (Si:H/CaF2) pairs were 34 min. The times to deposit comparable QW pairs by magnetron sputtering were 194 and 534 min, respectively. Advantages of this hybrid deposition method were reduced deposition times, optimum deposition process for each layer material, and improved optical and mechanical properties.