Investigation of surface morphology and ion activation of aluminium implanted 4H-SiC

Multiple-energy aluminium (Al+) implantation into 4H-SiC (0001) epilayer and activation anneal with a graphite encapsulation layer were investigated in this paper. Measurements showed that the implanted Al box doping profile was formed and a high ion activation ratio of 78% was achieved by 40 min annealing at 1600 degrees C using a horizontal chemical vapor deposition (CVD) reactor. The step bunching effect associated with the high temperature post implantation activation annealing (PIA) process was dramatically suppressed by using the graphite encapsulation layer. And a flat and smooth surface with a small average surface roughness (RMS) value of around 1.16 nm was achieved for the implanted 4H-SiC after the PIA process. It was demonstrated that this surface protection technique is a quite effective process for 4H-SiC power devices fabrication.