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Electrical and Thermal Performance of Ga₂O₃–Al₂O₃–Diamond Super-Junction Schottky Barrier Diodes

MetadataDetails
Publication Date2021-09-10
JournalIEEE Transactions on Electron Devices
AuthorsAbhishek Mishra, Zeina Abdallah, James W. Pomeroy, Michael J. Uren, Martin Kuball
InstitutionsUniversity of Bristol
Citations22

The design space of Ga<sub>2</sub>O<sub>3</sub>-based devices is severely constrained due to its low thermal conductivity and absence of viable p-type dopants. In this work, we discuss the limits of operation of a novel Ga<sub>2</sub>O<sub>3</sub>-Al<sub>2</sub>O<sub>3</sub>-diamond-based super-junction device concept, which can alleviate the constraints associated with Ga<sub>2</sub>O<sub>3</sub>-based devices. The improvements achieved using the proposed device concept are demonstrated through electrical and thermal simulations of Ga<sub>2</sub>O<sub>3</sub>-Al<sub>2</sub>O<sub>3</sub>-diamond-based super-junction Schottky barrier diodes (SJ-SBDs) and non-punch-through or conventional Schottky barrier diodes (NP-SBDs). The SJ-SBD enables operation below the R<sub>ON</sub>-breakdown voltage limit of Ga<sub>2</sub>O<sub>3</sub> NP-SBD, enabling >4 kV blocking voltage at R<sub>ON</sub> of 1-3 mΩ cm<sup>2</sup>. Here, the maximum switching frequency of SJ-SBD may be only a few kHz, as it is limited by the activation energy of acceptors (0.39 eV) in the diamond. Crucially, compared with NP-SBD, the use of diamond also results in ~60% reduction in temperature rise during static power dissipation. Polycrystalline diamond (PCD) properties depend on detailed microstructure and benefits compared to ideal Ga<sub>2</sub>O<sub>3</sub NP-SBD arise for diamond critical fields ≥6 MV/cm and thermal conductivities as low as 50-150 W/(m • K).