Structural impact of LPE buffer layer on sublimation grown 4H-SiC epilayers

摘要

The objective of this work was to study the effect of a liquid phase epitaxy buffer layer on the development of defects in sublimation grown epitaxial layers of 4H-SiC. The results were analyzed with the aid of optical microscope, scanning electron microscope, high-resolution X-ray diffraction and synchrotron white beam X-ray topography. A pronounced effect of the liquid phase epitaxy buffer layer on formation of dislocations and micropipes is observed in the sublimation epitaxy layers. It has been shown that during sublimation growth of epilayer with a thin liquid phase epitaxy buffer layer (0.1 μm) defects may undergo transformation and stacking faults can be formed. Sublimation grown epilayers grown on a thick liquid phase epitaxy buffer layer (1 μm) also showed a symmetrical distribution of misfit dislocations along the <1120> and [1100] directions.