Some Fundamental Topics On β-SiC Crystal Growth

As the only one among nearly 200 polytypes of different crystalline SiC, which has a cubic crystalline structure, p-SiC is an excellent candidate for fabrication of high power devices because of its high values of saturated electron drift velocity and electron mobility in comparison with the other SiC polytypes. In this thesis, some fundamental topics on p-SiC crystal growth such as the design of the crucible assembling system, the thermal field distribution and the liquid phase epitaxial growth of p-SiC films deposited on Si have been discussed. In brief, following major creative results have been obtained:1. A theoretical model for analyzing thermal system has been established via the analysis and discussion of the radial combining heat transferring in the graphic crucible system. Based on the model, a theoretical equation for designing the thermo-insulator and a design solution of the crucible assembling system has been suggested. Whereby, the designing problem in the heating system of crucible components is solved, and the graphic crucible component system in practical application is designed and manufactured.2. The finite element method (FE'.I) is adopted to analyze the effects of the numbers of coil turns, current intensity and current frequency upon the rate of joule heat generation in details. The thermo-radiation analytical countermeasures of various types are adopted to carry out the numerical analysis of the effects of the crucible with different shapes and sizes and the blind holes with different depths opened in the tops of crucibles as well as coil positions upon the thermal field distribution whereby solving the main problem of field the thermo-field design of the induction-heating SiC crystal growth system. A New combination idea of the thermo-field design obtained by means of the united design of the thermo-insulator and blind holes has been presented. The theoretical basis of the dynamic adjusting of coil positions for controlling over the thermo-fields based on the fluctuation effect of axial temperature gradient is suggested.3. The novel method of liquid phase epitaxial growth process of p-SiC from p-SiC film on Si substrate in C-saturated Si solvent is further investigated. Some processes of acquiring the fundamental technical parameters and some solution to some critical technical problems are introduced. Especially, the optimized technical schemes of effectively restraining such a-SiC polytypes as GH-SiC coring and growing in p-SiC epitaxial growth process is presented.4. The structural characteristics of the samples are analyzed. Much discussion on Roman spectroscopy of the samples is made in details, and the second-order scattering lines of SiC are found. The p-SiC crystal has been successfully grown from its thin film deposited on Si substrate.