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High-voltage vertical Ga2O3 power rectifiers operational at high temperatures up to 600 K

Forward I-V characteristics
Fig. 1. (a) Forward I-V characteristics of the fabricated vertical Ga2O3 SBDs.
   This work presents the high-temperature forward conduction and reverse blocking characteristics of high-voltage vertical Ga2O3 Schottky barrier diodes (SBDs) with bevel-field-plate edge termination. The qφb increases with T at 300-600° K, indicating the existence of barrier height inhomogeneity. Two competing reverse-bias leakage mechanisms have been identified. At 300-500° K, the TFE at the Schottky contact dominates the leakage current at low voltages, and the VRH in the depletion region dominates the leakage current at high voltages. At 500-600° K, the TFE model fits the leakage current over the entire voltage range up to 500 V. The high-voltage leakage current in our Ga2O3 SBDs shows a smaller increase with T when compared to state-of-the-art GaN and SiC SBDs, showing the great potential of Ga2O3 power rectifiers for high-temperature power applications.
   Our work presents the best combination of high-voltage and high-temperature performance in Ga2O3 power diodes. The highest operation temperature for our vertical Ga2O3 SBDs exceeds the ones reported for GaN and SiC SBDs with a similar operation voltage. When T increases from 300° K to 500° K, the leakage current of our Ga2O3 SBDs only increases by about 10-fold at 500 V, while an at least 100-fold leakage increase at 500 V is shown in vertical GaN and SiC SBDs with a similar BV. It is also worth mentioning that the high-temperature GaN and SiC SBDs typically have more complicated device designs, such as trench metal-oxide-semiconductor barrier Schottky (TMBS) or junction barrier Schottky (JBS) structures, while our Ga2O3 SBDs use a much simpler edge termination. These comparisons show the great potential of Ga2O3 SBDs for high- temperature and high-voltage power applications.
Reverse I-V characteristics
Fig. 2. (a) Reverse I-V characteristics of the fabricated vertical Ga2O3 SBDs.