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Chemical gas is a serious threat to the safety of human life gas general. Therefore, you need someone working and living environment, real-time content of the toxic ingredients in the efficient detection of the surrounding gas. Especially for highly toxic event may be high-risk areas. SAW gas sensor with its high sensitivity, fast response, small size, low cost, easy to carry, etc., stand out in many gas sensors. Especially high Q value, cladding SAW gas sensor has a higher detection sensitivity. However, the disadvantage of non-cladding layer of the SAW sensor is susceptible to the influence of the water vapor molecules to produce distortion of the noise signal in a certain extent, affect the accuracy of the SAW sensor. The diamond-like carbon (DLC) film having a high hardness, high resistivity, high thermal conductivity, low coefficient of friction and excellent chemical stability and corrosion resistance. It is highly incompatibility and the characteristics of the water molecules, also makes it can effectively eliminate the noise of water vapor to improve the detection accuracy of the uncoated SAW sensor. At the same time, the preparation of the DLC film having a low deposition temperature, the deposition rate is high, the film surface is smooth, a large area deposition, the substrate is a wide selection of simple equipment, making it the best choice of the protective film of the surface acoustic wave device . Paper, magnetic excitation radio frequency plasma enhanced chemical vapor deposition method (M-RF-PECVD), around the preparation of the diamond-like carbon, do the following work: 1, at room temperature, respectively, in the glass, and silicon (Si) substrate depositing a layer of diamond-like carbon film. And by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy (Raman) on some of the characteristics of the diamond-like carbon film characterization. From a large number of experimental data, summed up the reflected pressure to 30 Pa, the incident power of 50W, CH4/Ar = 5/90 of the experimental conditions, the surface of the hydrogen-containing DLC ??films prepared flat, compact structure, membrane-binding good, film sp3 key. 2, ZnO / Si and ZnO / diamond multilayer film structure as the target the first magnetron sputtering ZnO films grown on Si and diamond substrate, and then on ZnO / Si and ZnO / diamond structure RFPECVD Deposition of diamond-like carbon film, and the layers of the multilayer film structure by SEM characterization. The experiments show that the multilayer film structure, the degree of bonding between the layers of membrane structures. 3, proposed the idea of ??unpolished diamond deposition of diamond-like carbon film on a substrate, and a preliminary exploration. The results show that the deposition of DLC film after four hours, the diamond growth surface is too rough, no obvious changes. Contact surface morphology of the diamond with the substrate to be improved to some extent. In summary, the preparation of the DLC film major research, and through a series of tests to determine the optimal preparation of the DLC film. The DLC / ZnO / Si the DLC / ZnO / diamond and DLC / diamond multilayer film made a preliminary exploration. Laid the foundation for the low temperature deposition process of the DLC film and the uncoated SAW gas sensor.
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