In this work, high-stability 4H-SiC avalanche photodiodes (APDs) for ultraviolet (UV) detection at high temperatures are fabricated and investigated. With the temperature increasing from room temperature to 150°C, a very small temperature coefficient of 7.4 mV/°C is achieved for the avalanche breakdown voltage of devices. For the first time, the stability of 4H-SiC APDs is verified based on an accelerated aging test with harsh stress conditions. Three different stress conditions are selected with the temperatures and reverse currents of 175°C/100 μA, 200°C/100 μA, and 200°C/500 μA, respectively. The results show that our 4H-SiC APD exhibits robust high-temperature performance and can even endure more than 120 hours at the harsh aging condition of 200°C/500 μA, which indicates that 4H-SiC APDs are very stable and reliable for applications at high temperatures.

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