Low temperature annealing of 4H-SiC Schottky diode edge terminations formed by 30 keV Ar+ implantation

Edge termination of Schottky barrier diodes has been achieved using 30 keV Ar+ ions implanted at a dose of 1x10(15) cm(-2). The reverse-bias leakage c urrent is reduced by 2 orders of magnitude following postimplant annealing at a temperature of 600 degrees C. The thermal evolution of the implantatio n induced defects was monitored using positron annihilation spectroscopy an d deep-level transient spectroscopy. Two distinct defect regions are observ ed using the positron technique. The depth of the first is consistent with the range of the implanted Ar+ ions and consists of clustered vacancies. Th e second extends to similar to 250 nm, well beyond the range of the inciden t ions, and is dominated by point defects, similar in structure to Si-C div acancies. An implant damage related deep level, well defined at E-c-E-t=0.9 eV, is observed for both the as-implanted and the 600 degrees C annealed s ample. The effect of annealing is a reduction in the concentration of activ e carrier trapping centers. (C) 2000 American Institute of Physics. [S0021- 8979(00)04107-4].