【Member Papers】1380 V β-Ga₂O₃ trench MIS-type Schottky barrier diode with ultra-low leakage current

      Researchers from the University of Electronic Science and Technology of China have published a dissertation titled "1380 V β-Ga₂O₃ trench MIS-type Schottky barrier diode with ultra-low leakage current " in Japanese Journal of Applied Physics.

Background 

      β-gallium oxide (β-Ga₂O₃) is very attractive for high-voltage power devices, due to its wide bandgap ranging from 4.5 to 4.9 eV, high critical breakdown electric field of 8MV cm⁻¹, adjustable n-type doping concentrations spanning from 10¹⁴ to 10¹⁹ cm⁻³, moderate electron mobility of ∼200 cm² V⁻¹·s⁻¹ and relatively low production costs. Recently, β-Ga₂O₃ has been widely used to fabricate high-performance power devices, such as Schottky barrier diodes (SBDs), heterojunction PN diodes using p-type NiO (HJDs), metal–oxide semiconductor field-effect transistors, and modulation-doped field-effect transistors. Research on these devices shows that β-Ga₂O₃ is a promising material, and promotes the developments and applications of β-Ga₂O₃ power devices.

Abstract

      A β-Ga₂O₃ trench Schottky barrier diode (T-SBD) with double-field-plates terminal and cost-effective Al₂O₃/SiN dielectric layer is fabricated. Owing to the shielding effect of the trench metal–Insulator–semiconductor structure, compared with conventional SBD (C-SBD), the breakdown voltage of the T-SBD is improved from 700 V (C-SBD) to 1380 V (T-SBD) with specific on-resistance (R_on,sp) being 6.06 mΩ·cm². Compared to C-SBD, Baliga's figure of merit for the T-SBD is improved from 131 MW cm⁻² (C-SBD) to 314 MW cm⁻² (T-SBD). Moreover, the leakage current of T-SBD is significantly reduced from ∼0.33 mA cm⁻² (C-SBD) to ∼38 μA cm⁻² (T-SBD).

Summary

      In conclusion, we fabricated a β-Ga₂O₃ trench Schottky barrier diode with a double-field-plates terminal and costeffective Al₂O₃/SiN dielectric layer. Compared with conventional SBD, the breakdown voltage of T-SBD is improved from 700V (C-SBD) to 1380V (T-SBD), with little increase in R_on,sp. The Baliga’s figure of merit is improved by 139.7%. Moreover, the leakage current of T-SBD is significantly reduced by 88.5% compared to that of conventional SBD. This work shows that trench β-Ga₂O₃ SBD has great potential in the field of high-voltage and low-leakage current applications.

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