Effect of temperature on conversion of basal plane dislocations to treading edge dislocations during 4H-SiC homoepitaxiy

4H-SiC homoepitaxial layer grown on 4 degrees off-axis substrates is performed at various growth temperature by using the traditional chemical vapor deposition. The effect of growth temperature on propagation of basal plane dislocations from substrate to epitaxy was studied using the deep KOH etching and Synchrotron reflection X-ray topography, and the conversion mechanism was also investigated. It is found that the majority basal plane dislocations are converted to threading edge dislocations during epitaxial growth. Meanwhile, the two types of threading edge dislocations in epitaxial layer are observed after KOH etch. By the optimization of growth temperature, high quality epitaxial wafer with extremely low basal plane dislocations density (< 0.01 cm(-2)) can be obtained. The conversion rate is decreased during epitaxial growth with the increasing of growth temperature. It is suggested that the effective C/Si ratio on the growth interface is decreased at high temperature, leading to the suppression of lateral growth during epitaxial process.