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 degrees C-1600 degrees C. The samples were characterized using optical microscopy, atomic force microscopy, and Raman spectroscopy. The surface topog-raphy 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.