Ultra-wide-bandgap gallium oxide (Ga2O3) devices have recently emerged as promising candidates for power electronics; however, the low thermal conductivity (kT) of Ga2O3 causes serious concerns about their electrothermal ruggedness. This work presents the first experimental demonstrations of largearea Ga2O3 Schottky barrier diodes (SBDs) packaged in the bottom-side-cooling and double-side-cooling configurations, and for the first time, characterizes the surge current capabilities of these packaged Ga2O3 SBDs. Contrary to popular belief, Ga2O3 SBDs with proper packaging show high surge current capabilities. The double-side-cooled Ga2O3 SBDs with a 3×3 mm 2 Schottky contact area can sustain a peak surge current over 60 A, with a ratio between the peak surge current and the rated current superior to that of similarly-rated commercial SiC SBDs. The key enabling mechanisms for this high surge current are the small temperature dependence of on-resistance, which strongly reduces the thermal runaway, and the double-side-cooled packaging, in which the heat is extracted directly from the Schottky junction and does need to go through the low-kT bulk Ga2O3 chip. These results remove some crucial concerns regarding the electrothermal ruggedness of Ga2O3 power devices and manifest the significance of their die-level thermal management. 1

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This work describes the high-temperature performance and avalanche capability of normally-OFF 1.2-kV-class vertical gallium nitride (GaN) fin-channel junction field-effect transistors (Fin-JFETs). The GaN Fin-JFETs were fabricated by NexGen Power Systems, Inc. on 100-mm GaN-on-GaN wafers. The threshold voltage (V TH) is over 2 V with less than 0.15 V shift from 25 • C to 200 • C. The specific ON-resistance (R ON) increases from 0.82 at 25 • C to 1.8 m•cm 2 at 200 • C. The thermal stability of V TH and R ON are superior to the values reported in SiC MOSFETs and JFETs. At 200 • C, the gate leakage and drain leakage currents remain below 100 μA at −7-V gate bias and 1200-V drain bias, respectively. The gate leakage current mechanism is consistent with carrier hopping across the lateral p-n junction. The high-bias drain leakage current can be well described by the Poole-Frenkel (PF) emission model. An avalanche breakdown voltage (BV AVA) with positive temperature coefficient is shown in both the quasistatic I-V sweep and the unclamped inductive switching (UIS) tests. The UIS tests also reveal a BV AVA over 1700 V and a critical avalanche energy (E AVA) of 7.44 J/cm 2 , with the E AVA comparable to that of state-of-the-art SiC MOSFETs. These results show the great potentials of vertical GaN Fin-JFETs for medium-voltage power electronics applications.

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