Investigation of the growth processes and defect formation in epitaxial layers and bulk crystals of silicon carbide

The main objectives of this research work are: (1) SiC PVT (Physical Vapor Transport) epitaxial film growth and investigation of defect formation in silicon carbide bulk growth at the initial stage of crystallization; (2) SiC material characterization and defect observation in SiC bulk crystals; (3) SiC material processing for device fabrication.; The initial stage of crystallization on the seed, during PVT bulk SiC growth, was identified as a most important part of the sublimation growth process.; SiC PVT homoepitaxial film growth was successfully realized. The phenomena of micropipe termination was discovered and investigated. A model of the mechanism of micropipe formation and possible annihilation was developed and experimentally confirmed in this research; For the first time it is shown that by using a deposited graphite mask, it is possible to locally grow epitaxial layers on silicon carbide by PVT epitaxy. The locally grown islands show excellent crystalline structures with an absence of defect etch pits.; In this dissertation work an attempt is made to develop a model that enables determination of the influence of the instability of the growth conditions within growth cell on the SiC crystal growth parameters. The model of crystal growth, which takes into account, the surface processes such as vapor condensation, desorption, surface diffusion, atomic collisions, and probability of chemical reactions was successfully developed and the SiC crystal growth rate was estimated based on this model; Various techniques were developed to characterize defects in SiC bulk crystals. A new phenomena based on electrostatic charge generation in the vicinity of crystal imperfections, under electron beam bombardment, was discovered. A new design for a cathodoluminescence detector was proposed by us and successfully tested for SiC defect investigation.; A novel anodic oxidation technique to produce high quality SiO₂ films is presented. This technique shows great potential to form thick >1000 Å SiO₂ films on silicon carbide surfaces in a very short period of time (less than 5 minutes).; During the experimentation with anodic oxidation of SiC crystals under different conditions, the phenomena of selective electrochemical etching was discovered.