High-speed Homoepitaxial Growth of 4H-SiC

Homoepitaxial growth of 4H-SiC at 1400℃ was explored.The growth rate,surface morphology and defects of the epi-layers were studied.Raman characterization combined with KOH etching indicated that the epi-layers were 4H-SiC single crystal without 3C-SiC polycrystalline.In addition,low growth rate and high C/Si ratio were beneficial to convert the basal plane dislocations(BPDs) in substrate surface to threading edge dislocations(TEDs) at the sub-epi interface.Furthermore,the low growth rate was also favorable to reduce the defects generated during the growth process.With the growth rate increasing,the surface triangle defects and dislocations of the epilayers significantly increased.Most of these defects and dislocations were considered to be generated at the sub-epi interface at the beginning of the growth.By optimizing the interface layer at initial stage,a smooth transition from surface etching to epi-layer deposition can be achieved while the surface morphological defects and crystal defects are greatly reduced at high growth rate.