Computational studies of 4hydrogen and 6hydrogen silicon carbide

Silicon carbide (SiC), long touted as a material that can satisfy the specific property requirements for high temperature and high power applications, was studied quantitatively using various techniques. The electronic band structure of 4H SiC is examined in the first half of this dissertation. A brief introduction to band structure calculations, with particular emphasis on the empirical pseudopotential method, is given as a foundation for the subsequent work. Next, the crystal pseudopotential for 4H SiC is derived in detail, and a novel approach using a genetic algorithm search routine is employed to find the fitting parameters needed to generate the band structure. Using this technique, the band structure is fitted to experimentally measured energy band gaps giving an indirect band gap energy of 3.28 eV, and direct Γ, M, K and L energy transitions of 6.30, 4.42, 7.90 and 6.03 eV, respectively. The generated result is also shown to give effective mass values of m*MG = 0.66m0, m*MK = 0.31m0, m*ML = 0.34m0, in close agreement with experimental results.The second half of this dissertation discusses computational work in finding the electron Hall mobility and Hall scattering factor for 6H SiC. This disscussion begins with an introductory chapter that gives background on how scattering rates are derived and the specific expressions for important mechanisms. The next chapter discusses mobility calculations for 6H SiC in particular, beginning with Rode's method to solve the Boltzmann transport equation. Using this method and the transition rates of the previous chapter, an acoustic deformation potential DA value of 5.5 eV, an inter-valley phonon deformation potential D if value of 1.25×1011 eV/m and inter-valley phonon energy ħωif of 65 meV that simultaneously fit experimental data on electron Hall mobility and Hall scattering factor was found.