13th International Conference on Fracture June 16–21, 2013, Beijing, China -2- were calculated. As the results shown in Table 1, the projected range of crystalline SiC is shorter than hydrogenated amorphous SiC. Due to the existence of hydrogen atoms, hydrogenated SiC with the same width as crystalline SiC may suffers less radiation damage. As the distribution of incident protons in multiple layers of SiC/Si target is showed in Fig. 1, the protons are clustered at the center of projected range. Figure 1. The distribution of incident protons in SiC/Si target. 3. Experiments 3.1 Preparing of amorphous silicon carbide films 500nm amorphous SiC films are deposited on 4 in. (100) silicon substrates by PECVD at 300 °C. Some of the PECVD parameters are listed in Table 2. In order to get low-stress SiC films which are appropriate for fabricating MEMS structures, a furnace annealing process at about 450 °C for about 50 minutes is performed. Thus, the SiC films could be adjusted with a low tensile stress. Table 2. Parameters of PECVD Parameters of PECVD Values Flow rate of CH4 (sccm) 400 Flow rate of Ar (sccm) 400 Flow rate of NH3 (sccm) 5 Flow rate of SiH4 (sccm) 20 Pressure (mTorr) 1000 Power (W) 300 Temperature (°C) 300 3.2 Radiation on amorphous silicon carbide films The prepared silicon carbide films were radiated by energetic protons in an electrostatic tandem accelerator at room temperature for 2 hours. Table 3 illustrates some parameters of radiation experiments. In the accelerator, protons was accelerated to 1MeV. The protons beam was focused on a spot about 2×2 cm2. The current of the protons beam is 0.9μA, thus the flux reaches 1.4×1012 cm-2·s-1.
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