Exploitable results Stoichiometry and dopant effects on the crystallographic and electronic properties of silicon carbide crystals grown by the sublimation method Silicon carbide (SiC) is recognized as having great potential for electronic device applications involving high temperatures, high radiation, high frequencies and also high power. A prerequisite for the further advance of a SiC-based semiconductor technology is the availability of low defect bulk crystals with defined electronic and crystallographic properties as a substrate for highly perfect epitaxial layers. The present status of crystal quality does not meet this requirement. It is generally acknowledged that stoichiometry of the gas phase and dopants during sublimation growth of SiC are key parameters which can influence the crystal modification and defect generation and hence the electronic material properties. But there is a great lack of knowledge on the correlation of constitutional process conditions and crystal quality. In this research, the effect of dopants and stoichiometry on the crystallographic and electronic properties of SiC crystals, will be studied. The influence of the following parameters will be investigated: mechanical, chemical and thermal treatment methods on single crystallinity; impurity doping and SiC composition of the gas phase on stabilization of polytypes during the crystal growth process; and transition metal doping on the electronic properties. Optical, electrical and microstructural properties of the prepared crystal specimens will be analyzed by different characterization methods, e.g. photoluminescence, DLTS, and scanning electron microscopy. Numerical modelling of heat and mass transfer will be applied to give information on the constitutional conditions during the crystal growth process. The results of experimental and numerical studies will be compared to existing theories on polytype formation in SiC. Based on this analysis, concepts for the development of more advanced models on polytypism will be carried out. È in corso la ricerca di dati su OpenAIRE... Si è verificato un errore durante la ricerca dei dati su OpenAIRE Nessun risultato disponibile
