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

Abstract

Edge termination of Schottky barrier diodes has been achieved using 30keV Ar+ ions implanted at a dose of 1 × 1015cm2. The reverse-bias leakage current is reduced by 2 orders of magnitude following postimplant annealing at a temperature of 600 °C. The thermal evolution of the implantation induced defects was monitored using positron annihilation spectroscopy and deep-level transient spectroscopy. Two distinct defect regions are observed using the positron technique. The depth of the first is consistent with the range of the implanted Ar+ ions and consists of clustered vacancies. The second extends to ∼250 nm, well beyond the range of the incident ions, and is dominated by point defects, similar in structure to Si-C divacancies. An implant damage related deep level, well defined at Ec-Et-0.9 eV, is observed for both the as-implanted and the 600 °C annealed sample. The effect of annealing is a reduction in the concentration of active carrier trapping centers. © 2000 American Institute of Physics.