Fabrication and characterization of 4H-SiC APDs for high-temperature ultraviolet detection applications

In this work, 4H-SiC avalanche photodiodes (APDs) were fabricated and investigated both in linear and Geiger modes for high-temperature ultraviolet (UV) detection applications. With the temperature varying from 300 K to 425 K, the avalanche breakdown voltage of our 4H-SiC APDs keeps very stable with a small temperature coefficient of <8 mV/K. In the Geiger mode, the impact of temperature on the output signal pulse height, dark count rate (DCR) and single-photon-detection efficiency (SPDE) is analyzed from the aspect of device physics. At a fixed bias voltage of 166.5 V, the DCR and SPDE at 300 K, 375 K and 425 K are 5.3 Hz∙μm^-2 /15.6%, 11.8 Hz∙μm^-2 /17% and 16.5 Hz∙μm^-2 /15.7%, respectively. The results in this work demonstrate that our fabricated 4H-SiC APDs can operate stably and reliably under the conditions with a high temperature.