Speaker
Description
In recent years, there has been a shift towards investigating wide bandgap (WBG) semiconductors due to their advantageous material properties that could lead to better performing detectors. 4H-SiC has been the primary material of interest in developing low gain avalanche detectors (LGADs) for high energy physics applications due to their potentially higher radiation hardness and their reduced leakage current which can reduce the cooling requirements needed in collider facilities. This study focuses on recent progress in investigating the radiation hardness of 4H-SiC LGADs by irradiating devices with neutrons at the Rhode Island Nuclear Science Center (RINSC) to fluences up to 1x1015 neq/cm2. Electrical characterization (I-V, I-V-T, C-V) showed a loss of rectification, increased device resistance, increased ideality factor, and a loss in voltage-dependent capacitance with increasing fluence indicating signs of defect generation which causes carrier removal. UV-TCT results showed gain suppression but also signs of certain layers in the epitaxial stack “failing” (its doping level changing significantly), indicating the need to monitor the degradation of each layer. The device physics of a neutron irradiated LGAD is presented in hopes of understanding the gradual degradation of its performance while also motivating the need to push for methods to improve the radiation hardness of 4H-SiC.