Observation of Regions with Low Schottky Barrier Height in 4H-SiC by the Electrochemical Deposition(Session9B: GaN and SiC Device Process Technology)

概要

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4H-SiC Schottky diodes are promising devices for the application of high-power and high-frequency rectifiers. However it has been reported that the forward bias property of 4H-SiC Schottky diodes is not uniform among the fabricated diodes because of inhomogeneity of the Schottky barrier height. In this study, we observed regions with a low Schottky barrier height on 4H-SiC surface by the electrochemical deposition of ZnO. Then we fabricated Ni Schottky diodes after ZnO removal to clarify regions with the low Schottky barrier height, and we compared the Schottky barrier height between the contacts on regions with and without ZnO deposition. Schottky barrier heights of the contacts covering a ZnO deposited area were lower than the contacts without a ZnO deposited area. The molten salt etching revealed that most of the ZnO films were deposited on the position with etch pits, but a part of films were deposited on positions without an etch pit. The regions with low Schottky barrier height originate from not only etch pit defect but also other kinds of defects.
社団法人電子情報通信学会の論文
2008-07-02