Current-voltage characteristics of isotype SiC-SiC junctions fabricated by direct wafer bonding

摘要

Results obtained in a study of current-voltage characteristics of isotype SiC-SiC structures fabricated by direct bonding of single-crystal n-type 6H-SiC wafers with a donor concentration of similar to 10(16)cm(-3) are presented. The initial wafer bonding was done in deionized water. To enhance the adhesion, the structure was thermally annealed at 1250 degrees C. All the features of the current-voltage characteristics measured are consistently explained in terms of the hypothesis that the SiC-SiC interface is a variable-thickness channel filled with a native SiOx oxide of thickness 10-100 nm. The minimum experimentally measured differential resistance of the structure (6 ohm cm(2)) is limited by the current transport in the oxide layer, which occurs by the mechanism of space-charge-limited currents.