| As a kind of new semiconductor material, silicon carbide exhibits several outstanding physical and chemical properties, such as wide band gap, high breakdown electric field, high electron mobility, high thermal stability, and it is compatible with technology of silicon integrated circuit. So SiC is regarded as the most potential material in many fields such as high temperature, high frequency, high power, high irradiation, and the preferential material of non-volatile memory and photoelectric integrated devices. It is also an effective luminous material. Therefore, SiC has been a hotspot in the fields of ne\v materials, microelectronics and photoelectron. The preparation of SiC films and the experiment results are given in details.In the first part of the thesis the current status of SiC films is summarized. In recent years epitaxial monocrystalline SiC films have been intensively investigated and many authors reported the studies of the SiC structures and photoelectric properties. However it seems that the properties of amorphous SiC films, especially those prepared using magnetron sputtering, are not yet clear. So it is necessary to investigate the SiC films prepared using magnetron sputtering. It is expected to find inventive results so as to promote the development of photoelectric devices. In addition, the annealing process of SiC films is mostly carried out in vacuum, argon gas or nitrogen gas ambience. It is the first time to report that the SiC films have been annealed in hydrogen gas ambience.Besides, the detailed process of our experiment is given out. The samples were prepared in JCK-500A magnetron sputtering system equipped with radio frequency generator. The samples were annealed in an open tube furnace withan ambience of high purity nitrogen or hydrogen ambience respectively. Fourier transform infrared transmission spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM). scanning electron microscopy (SEM), atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS) were employed to analyze the structure, composition as well as surface morphology of the as-deposited films and the annealed ones. The photoluminescence was also measured at room temperature.Experimental results are presented. First, the effects of annealing temperature on SiC film annealed in N? ambience are given systematically. The crystalline quality of SiC films is greatly improved. Compared with the IR absorption frequency of bulk SiC, a blue shift at 813cm"1 is observed. No change takes place when temperature is below 1000癈. Both XRD measurements and TEM observance show that SiC films have changed into pol\ cr\ stalline after annealing. SEM results show the formation of nanowires after annealing at the temperature of 1150CC. AFM images demonstrate the variation of SiC particles. The size of SiC particles increases with the annealing temperature. The SiC particles take on spoon-like tails after annealing at the temperature of 1000癈 or higher. The annealing effects on SiC films in Kb ambience is followed. The difference between the annealing effects in N2 and H2 ambience on SiC films are presented. The results show that annealing in H2 ambience is more effective to improve the crystalline quality of SiC film than in NT ambience. The carbon nanowires can be formed at the temperature of 1000癈 or higher during H: annealing. The diameters of carbon nanowires vary between 20 to 60 nm. The length of carbon nanowires is about 8-9 n m and some are even over 10 u m. Regarding the formation mechanism of the nanowires, we speculate that it is due to the excess carbon formed during sputter deposition. It is the first time to report the annealing oSiC films in H2 ambience. To the best of our knowledge, the synthesis of carbon nanowires using magnetron sputtering method has not been reported previously. It should be noted that carbon nano-spiral wires can be formed by similar method. The diameters of carbon nanowires vary between 70 to 100 nm while the diameters of spiral tubes var... |
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