Design and simulation of a novel 4H-SiC LGAD timing device

Silicon-based fast timing detectors have been widely used in high-energy physics, nuclear physics, space exploration and other fields in recent years. However, silicon detectors often require complex low-temperature systems when operating in irradiation environment, and their detection performance decreases with the increase in the irradiation dose. Compared with silicon, silicon carbide (SiC) has a wider band gap, higher atomic displacement energy, saturated electron drift velocity and thermal conductivity. Simultaneously, the low-gain avalanche detector avoids cross talk and high noise from high multiplication due to its moderate gain, and thus can maintain a high detector signal without increasing noise. Thus, the 4H-SiC particle detector, especially the low-gain avalanche detector, has the potential to detect the minimal ionizing particles under extreme irradiation and high-temperature environments. In this work, the emphasis was placed on the design of a 4H-SiC low-gain avalanche detector (LGAD), especially the epitaxial structure and technical process which play main roles. In addition, a simulation tool—RASER (RAdiation SEmiconductoR)—was developed to simulate the performances including the electrical properties and time resolution of the 4H-SiC LGAD we proposed. The working voltage and gain effectiveness of the LGAD were verified by the simulation of electrical performances. The time resolution of the LGAD is (35.0 ± 0.2) ps under the electrical field of −800 V, which is better than that of the 4H-SiC PIN detector.