Activation of Implanted Al and Co-Implanted Al/C or Al/Si in 4H-SiC

Rsh, CL, EPR, RBS, and TEM measurements were made on samples implanted with Al, Al and C, or Al and Si to a depth of 0.3 μm with a concentration of 10 20 cm -3 and annealed with an AlN cap. Rsh measurements suggest that at the lower annealing temperatures the implanted C facilitates the chemical reactions for the incorporation of Al into a Si site and Si impedes it, but for annealing temperatures >1600°C the co-implants have little effect because the activation energy for these reactions is no longer the rate determining step. The CL measurements show that the peak near 3.0 eV associated with a free electron recombining with a hole bound to an Al acceptor decreases as the annealing temperature increases suggesting defects are trapping out the holes. This can explain the lower mobilities, lower electrical activation, and our inability to detect the EPR peak associated with AlSi in these heavily implanted samples. Our RBS and TEM measurements suggest that these defects are extended residual defects that nucleate and grow, as opposed to being annealed out, and that they could be stacking faults.