Acceptor incorporation in SiC epilayers grown at high growth rate with chloride-based CVD

Abstract

A systematic p-type doping study has been performed on 4H- and 6H-silicon carbide (SiC) epilayers grown at high growth rate using chloride-based chemical vapor deposition. The effect of temperature, pressure, growth rate, C/Si-, Cl/Si-ratios and dopant flow on the incorporation of the acceptor atoms aluminum and boron has been studied. The C/Si-ratio on the aluminum incorporation has similar behavior to what has been reported for the standard non-chlorinated low growth rate process, while no clear effect of C/Si-ratio was observed for the boron incorporation. A higher Cl/Si-ratio seems to lead to lower the aluminum and boron incorporation either due to more effective silicon supply at high Cl/Si-ratio or due to removal of dopant atoms from the surface by chlorine. The doping concentration is stable to the variations in silicon molar fraction, growth pressure and growth temperature for the aluminum-doped layers. Also p-type doping with gallium was tested.