Synthesis of high purity polycrystalline silicon carbide for radiation dosimeter application
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Date
2016-06
Authors
Foong Suet Kay
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Abstract
In this research, the synthesis of high purity polycrystalline silicon carbide (SiC) at 400°C to 600°C and its efficacy in radiation dosimetry system are the two main concerns and were investigated. The synthesis of SiC was initiated from raw material of aluminium carbide (Al4C3) and silicon tetrachloride (SiCl4). Al4C3 was synthesized from aluminium (Al) powder and graphite (C) powder by wet mixing method. Both Al and C possessed average size of 9.37μm and 7.87μm respectively. Al4C3 was deposited on p-type Si wafer using e-beam evaporation technique, with an average emission current of 75mA and average coating rate of 0.9 Å/s. The deposited Si wafer was reacted with flowing SiCl4 in quartz tube with combinations of 400°C to 600°C for 1 hour to 3 hours. The effects of these parameters on the formation of SiC were characterized by X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray (FESEM-EDX), Inductive Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), and Fourier Transform Infrared Spectroscopy (FTIR). SiC peak at 33° in XRD can be observed in design of experiment (DOE) run 4, whereas Si-C bond stretching was observed at around 800cm-1 in all DOE runs, with regards to FTIR data. FESEM-EDX showed elemental composition of Si, C, Al and O, suggested that oxidation happened altogether with carbothermal reduction process. Al presented ICP-OES has proved the carbothermal reduction process took place. By using statistical DOE, reaction time found to play the most significant role in the synthesis of SiC, while higher reaction temperature can further enhance the formation of SiC.