The Study Of SiC Single Crystal Growth

Silicon carbide (SiC), as one of the third-generation wide band-gapsemiconductor materials, has great potential applications in high temperature, highfrequency, high power electronic devices owning to its wide band-gap, high thermalconductivity, high electron saturation drift velocity and excellent anti-radiation ability.Nowadays, the fabrications of SiC single crystal wafers, in particular for large-sizeSiC single growth and processing, are still challenging in China because of thedelayed start study. This thesis performed some studies on some key technologies ofSiC single crystal growth, including the improvement of the SiC crystal growthtechnology, the optimization of the growth devices and the recycling of abrasive. Theresults are as follows:First, the formation mechanism of the high-temperature line on the used sourceand the split of crystal were investigated. The key to solve the split of crystal is todecrease the radial temperature gradient. A temperature gradient model in chamberwas proposed and the feasible way to solve the problem was to elevate the seedlocation.Second, a pulling locator for the seed rod was designed and more accuratelocation of crucible filled with raw materials can be achieved. The pulling locator issimply made and can be used conveniently.Third, the purification technique of the diamond abrasive was exploited, whichinvolved the chemical cleaning and anneal in ambient atmosphere. Most the metal andgraphite in the diamond abrasive can be removed. The technique is helpful to decreasethe costs of crystal processing.Finally, standard manners for raw material heating and loading were suggested.The crystallization state of the raw material surface was added in the criterion toexamine the heating treatment of source. The influence of sizes of SiC particles on thefill of crucible was analyzed and a vibration process is suggested to to make the raw materials’ mass nearly same.The technological amendments made in the thesis are expected to be useful toimprove the efficiency and decrease cost of SiC production.