Microscopic investigation of SiO2/SiC interface using super- higher-order scanning nonlinear dielectric microscopy

SiO2/SiC interface was investigated with high spatial resolution by super-higher-order scanning nonlinear dielectric microscopy (SHO-SNDM). Comparison of non-oxidized and thermally oxidized 4H-SiC wafer revealed that only 5 minutes oxidation makes the interface quality spatially inhomogeneous. SiC wafers with and without post oxidation annealing (POA) in NO ambient were also compared, which showed that the spatial deviation of interface quality was reduced by the treatment. In addition, using SHO-SNDM, local capacitancevoltage (C-V) curves were two dimensionally mapped and compared between the two SiC wafers (with/without POA). The local C-V curve obtained in sample with POA was more close to ideal C-V curve (larger voltage dependence and less hysteresis) compared to the C-V curves obtained in sample without POA. This result indicates that the POA treatment reduced the interface state density. A voltage dependence of SNDM image was calculated using reconstructed C-V curves. This analysis showed that inhomogeneous in SNDM image was reduced as the voltage was increased, which might be related with interface states. SHO-SNDM is promising technique for investigation of SiO2/SiC interface quality. Corresponding author. [email protected] Tel: +81 (22) 217 5526 ; Fax: +81 (22) 217 5526 Microscopic investigation of SiO2/SiC interface using super-higherorder scanning nonlinear dielectric microscopy N. Chinone *1 , R. Kosugi 2 , Y. Tanaka 3 , S. Harada 2 , H. Okumura 2 , and Y. Cho 1 * Corresponding author. [email protected] Tel: +81 (22) 217 5526 ; Fax: +81 (22) 217 5526