Deep Levels Generated by Thermal Oxidation in n-Type 4H-SiC

The Z(1/2) center (E-C - 0.67 eV), which is a lifetime killer in n-type 4H-SiC epilayers, is reduced by thermal oxidation. The oxidation, however, simultaneously generates other deep levels: ON1 (E-C - 0.84 eV) and ON2 (E-C - 1.1 eV) centers. From the behaviors (generation condition, thermal stability, and change in the depth profiles) of the ON1 and ON2 centers in samples (i) oxidized in O-2, (ii) implanted with C+ or Si+ atoms, and (iii) oxidized in N2O (or NO), we suggest that these defects may originate from the same defect in different charge states, related to both carbon interstitials and N atoms. (C) 2013 The Japan Society of Applied Physics