Cristobalite formation on high-temperature oxidation of 4H-SiC surface based on silicon atom sublimation

Two innovative high-temperature oxidation methods for 4H-SiC were developed, with observations made via Optical Microscope, Scanning Electron Microscope and Raman spectrum. We successfully fabricated fully crystallized cristobalite films through oxidation and annealing processes, unveiling the lateral growth mechanisms of crystal planes during annealing. The study also delved into the unusual effects of Si sublimation on the oxidation rate of cristobalite during its formation and investigated the stress-induced cracking phenomena observed when the film thickness exceeds 1 μm. Additionally, a novel step oxidation technique was introduced to suppress vapor phase oxidation of Si at high temperatures by employing a barrier layer, facilitating the swift production of amorphous SiO2 thick films. The exceptional surface and interface flatness exhibited by these films underscore their significant potential for applications in the realm of functional films. [Display omitted] •Controlled growth of cristobalite and amorphous SiO2 films was made based on Si sublimation oxidation.•The phenomenon of anomalous oxidation rates between Si and C faces during Si sublimation was elucidated.•Stress-induced cracking phenomena in cristobalite were analyzed through Raman spectra.•High quality of interface between amorphous SiO2 and SiC was prepared using a rapid thick film process.