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2.5 kV Vertical Ga2O3 Schottky Rectifier with Graded Junction Termination Extension
Year: 2023 | Author: Boyan Wang | Paper: H1.6
Fig. 1. (a) Schematic of the Ga2O3 SBD with NiO JTE. (b) Simulated E-field contour at 2500 V. (d) E-field profile in Ga2O3 at voltages from 0.5 to 2.5 kV.
The fabrication of this JTE obviates the etch or implantation and shows good throughput. Two Schottky metals without different work functions (Ni and Pt) are used in device fabrication. The use of Pt is found to be critical to lowering the leakage current and exploiting the JTE functionality. As shown in Fig. 2, the fabricated Ga2O3 SBDs exhibit a forward voltage below 1.9 V at the current density of 100 A/cm3, a differential specific on-resistance of 5.9 mΩ.cm2, and a breakdown voltage over 2.5 kV.
Fig. 2. Forward I-V characteristics in (a) linear and (b) semi-log scale. (c) Reverse I-V characteristics of non-JTE SBDs, Pt-SBDs, Ni-SBDs, and PN-diodes (PNDs). Four devices at different sample locations are shown for each device type.
The Baliga's figure of merit (FOM) exceeds 1 GW/cm2 and is among the highest in multi-kilovolt Ga2O3 SBDs. Besides, the capacitance of the JTE region is extracted, allowing for evaluation of the capacitance, charge, and switching FOM of 1.7 kV-class Ga2O3 SBDs with varied current ratings. The results show good promise of Ga2O3 SBDs for kilovolt power electronics.
