Radiation Hardness of Si Compared to 4H-SiC for Betavoltaics Assessed by Accelerated Aging Using an Electron Beam System

Abstract

With the advancement of three-dimensional electronic technologies, 3D betavoltaics consisting of a mixture of a semiconductor converter and a beta emitter have been investigated to increase output power by maximizing the beta absorption in the semiconductor. Semiconductor radiation robustness has typically been evaluated by monitoring electrical properties during the beta irradiation process over a long dwell time. To quickly and safely assess semiconductor candidates for betavoltaics without incorporating high-activity beta emitters, a custom-designed electron beam system as a beta source surrogate has been used. In this work, we report the change of electrical performance of planar 4H-SiC, planar Si, and 3D Si ridge p-i-n diodes irradiated by high-flux and high-fluence electrons. The 4H-SiC diodes were found to suffer 45% degradation to output power with 100 keV electron irradiation at a fluence of 1.3 × 1018 cm−2; however, the Si diodes showed no decrease in performance at the highest fluence of 100 keV electron irradiation of 7 × 1018 cm−2. This demonstrates that Si is more radiation hard than 4H-SiC for 147Pm-based betavoltaics, with an average beta energy of 62 keV.