Using vapour-liquid-solid mechanism for SiC homoepitaxial growth on on-axis α-SiC (0001) at low temperature

The vapour-Liquid-Solid mechanism was used for growing epitaxial SiC layers on on-axis 6H-SiC and 4H-SiC substrates. By feeding Al70Si30 melts with propane, homoepitaxial growth was demonstrated down to 1100 degrees C on both polytypes. At this temperature, the surface morphology is rough and non uniform with spiral growth forming large hillocks at the places where screw dislocations emerge from the substrate. Raman spectroscopy confirms the absence of the 3C-SiC polytype and shows the high Al doping of the layers. This growth temperature of 1100 degrees C is the lowest one ever reported for growing homoepitaxial layers on low tilt angle SiC substrates. Increasing the temperature to 1200 degrees C eliminates these hillocks but creates other morphological features due to fast substrate etching at this high temperature before growth starts.