Simulations on 4H-SiC-based Vertical PN⁻PN-structure Radiation Detectors with Internal Gain

4H-silicon carbide (4H-SiC)-based NPN bipolar radiation detectors have achieved an internal gain of 10. However, enhancing the gain property remains challenging due to the constraints imposed by the product of carrier mobility and lifetime of the SiC material. To address this issue and obtain a higher internal gain, an optimized PN-PN-based radiation detector was proposed in this paper, which could be interpreted as a cascaded NPN-PNP topological structure. Technology computer-aided design (TCAD) Sentaurus simulations demonstrate that the optimized PN-PN detector exhibits a gain twice that of the NPN detector, with a recovery time of 31.37 ms. Additionally, the gain-limiting factors and operational modes of the optimized PN-PN radiation detector were thoroughly discussed.