High-Temperature Performance of SiC NPN X-Ray Detector

In this paper, the temperature-dependent X-ray response performance of a two-terminal 4H-SiC npn detector was investigated over the temperature range from 300 K to 500 K. The results indicated a notable reduction in the response current as the temperature increased. Specifically, the sensitivity(S)dropped by 35.6% to 71.24%, the noise-equivalent dose rate(NED)increased by an order of magnitude, and the internal gain(Gain)decreased by 35.63% to 71.23% at various dose rates from 0.1915 Gy·s-1to 1.532 Gy·s-1. Tests and analysis using a SiC PIN detector with a depletion region of the same thickness as that of the SiC npn detector revealed that the degradation observed in the SiC npn detector can be attributed to reduced charge collection efficiency related to mobility and lifetime of carriers within the thick depletion region. Additionally, TCAD simulations of the carrier mobility-lifetime product were conducted to illustrate the high-temperature effect on the charge collection efficiency in the 30 μm depletion region of the SiC npn detector, which is essential for the effective collection of high-energy X-ray photons. This work provided new insight into the feasibility of SiC npn detectors for high-temperature applications.