Effect of temperature on growth of epitaxial layer on semi-insulating 4H-SiC substrate

4H-SiC has excellent physical and chemical properties such as wide band gap and high electron mobility and can be used in microwave and radio frequency devices. Epitaxial layer on semi-insulating (SI) substrate of 4H-SiC is a key structure for the fabrication of radio frequency devices. However, two-dimensional growth easily occurs during the epitaxy process to form 3C-SiC. Therefore, it is necessary to study the crystal polytype change in the epitaxial layer. This paper studied the effect of temperature on the epitaxial layer during epitaxy on 4H-SiC SI substrates using trichlorosilane and ethylene as source gases. The Si-face and the C-face were respectively selected as the growth planes, and the temperature varied in the range of 1400℃–1600℃. The samples were characterized using optical microscopy, atomic force microscopy, and Raman spectroscopy. The surface topography obtained by epitaxial growth was uniform, and the surface roughness of the smooth region was less than 1.0 nm. 3C-SiC was obtained at low temperature, and 4H-SiC was obtained at higher temperature.