Effect of surface irregularities on diamond Schottky barrier diode with threading dislocations

• Published in: Diamond and related materials 2022-08, Vol.127, p.109188, Article 109188
• Main Authors: Mikata, N., Takeuchi, M., Ohtani, N., Ichikawa, K., Teraji, T., Shikata, S.
• Format: Article
• Language: English
• Subjects: Crystal dislocations; Crystal structure; Crystallinity; Defects; Diamond; Diamonds; Dislocation; Forward characteristics; Hillock; Irregularities; Leakage current; Pit; Power device; Schottky barrier diode (SBD); Schottky diodes; Silicon carbide; Threading dislocations; Wide bandgap semiconductors
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2022.109188

Pyramidal and flat-type hillocks, both known for having a threading dislocation in the center, are utilized to examine the effect of surface irregularities on the characteristics of Schottky barrier diodes (SBDs). By performing RAMAN mapping on both hillocks, crystalline imperfections in three dimensions with clear strain are observed. Surface scanning images obtained via atomic force microscopy show an extremely large surface protrusion with a maximum height of approximately 15 nm in the pyramidal hillock. Owing to crystalline imperfections in the threading dislocation region, the SBDs fabricated on the dislocations exhibit inferior forward characteristics. However, high reverse leakage currents are only observed in dislocations on pyramidal hillocks with surface protrusions, whereas low reverse currents are observed in the flat hillock region without surface irregularities. The phenomenon above is consistent with the characteristics of wide bandgap semiconductors such as silicon carbide. [Display omitted] •Effects of surface irregularities on the characteristics of Schottky barrier diodes are studied.•SBDs fabricated on the dislocations exhibit inferior forward characteristics.•High reverse leakage currents are only observed in dislocations on pyramidal hillocks with surface protrusions.