A Comparative Study on the Electrical Properties of Vertical ((2)over-bar01) and (010) beta-Ga2O3 Schottky Barrier Diodes on EFG Single-Crystal Substrates

作者：Fu Houqiang; Chen Hong; Huang Xuanqi; Baranowski Izak; Montes Jossue; Yang Tsung Han; Zhao Yuji^*

来源：IEEE Transactions on Electron Devices, 2018, 65(8): 3507-3513.

DOI：10.1109/TED.2018.2841904

• Crystal anisotropy
• gallium oxide
• power electronics
• Schottkybarrier diodes (SBDs)
• semiconductor

This paper reports a comprehensive study on the anisotropic electrical properties of vertical (201) and (010) beta-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 m Omega . cm(2), 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 cm(2)/(V . s), respectively, with an on-current of similar to 1.3 kA/cm(2) and on/off ratio of similar to 10(9). 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 tunnelingmodel 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 beta-Ga2O3 can affect the electrical properties of vertical SBDs and should be taken into consideration when designing beta-Ga2O3 electronics.

• 出版日期2018-8