Study of annealing conditions on the formation of ohmic contacts on p+ 4H–SiC layers grown by CVD and LPE

The quality of Al/Ti-based ohmic contacts formed on 4H–SiC films under various annealing conditions has been examined. Atmospheric, vacuum and high vacuum environments as well as resistive, inductive and rapid thermal heating have been used. Vacuum annealing resulted in non-oxidized contacts independent of the heating method. The ohmic contacts were fabricated on both highly doped (1×1018 cm−3) CVD-grown and extremely high doped (>1×1020 cm−3) LPE-grown films. Reproducible and of low specific contact resistance (∼1×10−4 Ω cm2) contacts were obtained only for the case of LPE-grown films.