A Comparative Study on the Electrical Properties of Vertical (201) and (010) β-Ga₂O₃ Schottky Barrier Diodes on EFG Single-Crystal Substrates

Houqiang Fu, Hong Chen, Xuanqi Huang, Izak Baranowski, Jossue Montes, Tsung Han Yang, Yuji Zhao

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

This paper reports a comprehensive study on the anisotropic electrical properties of vertical (201) and (010) β -Ga₂O₃ Schottky barrier diodes (SBDs). The devices were fabricated on single-crystal substrates grown by an edge-defined film-fed growth method. The temperature-dependent current-voltage (I-V) and capacitance-voltage (C-V) characteristics were systematically measured, analyzed, and compared. The (201) and (010) SBDs exhibited on-resistances (RON) of 0.56 and 0.77 mΩ · cm², turn-ON voltages (VON) of 1.0 and 1.3 V, Schottky barrier heights (SBHs) of 1.05 and 1.20 eV, electron mobilities of 125 and 65 cm²/(V· s), respectively, with an on-current of ~ 1.3 kA/cm² and on/off ratio of ~ 10⁹. The (010) SBD had a larger VON and SBH due to anisotropic surface properties (i.e., surface Fermi level pinning and band bending), as supported by X-ray photoelectron spectroscopy measurements. Temperature-dependent I-V also revealed the inhomogeneous nature of the SBH in both devices, where the (201) SBD showed a more uniform SBH distribution. The homogeneous SBH was also extracted: 1.33 eV for the (201) SBD and 1.53 eV for the (010) SBD. The reverse leakage current of the devices was well described by the two-step trap-assisted tunneling model and the 1-D variable range hopping conduction model. The (201) SBD showed a larger leakage current due to its lower SBH and/or smaller activation energy, and thus a smaller breakdown voltage. These results indicate that the crystalline anisotropy of β -Ga₂O₃ can affect the electrical properties of vertical SBDs and should be taken into consideration when designing β -Ga₂O₃ electronics.

Original languageEnglish (US)
JournalIEEE Transactions on Electron Devices
DOIs
StateAccepted/In press - Jun 8 2018

Keywords

  • Anisotropic magnetoresistance
  • Crystal anisotropy
  • Crystals
  • Gallium
  • gallium oxide
  • Optical surface waves
  • power electronics
  • Rough surfaces
  • Schottky barrier diodes (SBDs)
  • semiconductor.
  • Substrates
  • Surface morphology

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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