Papers by Author: Tomoaki Furusho

Abstract: The effects of basal-plane defects on the performance of 4H-SiC Schottky diodes using a Ni electrode are demonstrated. Systematic characterization was performed using 4H-SiC epitaxial layers grown by sublimation epitaxy on substrates with various off-axis angles. As the off-axis angle increases, the ideality factor of the current-voltage characteristics increases, and the Schottky barrier height decreases, corresponding to an increase in the number of basal-plane defects. The reverse-bias current degrades for high off-axis samples. These results indicate that basal-plane defects degrade the device performance. Schottky diodes that possesses good characteristics were obtained for samples with low off-axis angles (2o- and 4o-off samples).

Abstract: 4H-SiC was grown on 4H-SiC (1100) substrates by sublimation boule growth, and transmission electron microscopic investigation was carried out. Two basal-plane-dislocations in the same basal plane (the BPD pair), whose dislocation line extend toward the [1100] growth direction, were observed as aligned along [0001]. The density of the BPD pairs along [0001] was in the same order with that of the stacking faults in the sample. A threading screw-dislocation was observed in between aligned BPD pairs. It is proposed that the interaction between stacking faults and threading screw-dislocations on the grown surface generates the BPD pairs. Since a high density of stacking faults is inherent to the growth on the substrates perpendicular to (0001), keeping an atomically flat grown surface is important to prevent the generation of the threading screw-dislocations, and thus to suppress the generation of the BPD pairs in case of the growth on (1100) and/or (11 2 0) substrates.

Abstract: The dependence of donor-acceptor pair (DAP) emission properties on impurity concentrations of N and B in 6H-SiC epilayers was investigated. Doped samples were grown by closed sublimation technique, and impurity concentrations were confirmed by secondary ion mass spectrometry (SIMS). Photoluminescence (PL) measurement results indicate that p-type 6H-SiC with NA>ND had extremely low DAP emission efficiency, whereas n-type 6H-SiC with NA

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