The study of 4H-SiC LGAD after proton radiation

TL;DR

This study evaluates the radiation hardness of a SiC-based LGAD detector under proton irradiation, revealing significant electrical property changes and developing a model linking defect characteristics to performance degradation.

Contribution

It introduces a comprehensive analysis of SiC LGAD radiation effects and a defect-based degradation model validated by experimental data.

Findings

Leakage current reduced by 2-4 orders of magnitude after irradiation

Charge collection efficiency decreases by approximately 50%

The developed model accurately predicts electrical degradation based on defect characteristics

Abstract

Silicon carbide (SiC) is a promising material for radiation monitoring in harsh environments, due to its low dark current, high breakdown voltage, high thermal conductivity, and radiation hardness.~This work investigates a SiC-based Low-Gain Avalanche Detector (LGAD), named SICAR, with a gain factor of~2 to 3, under 80 MeV proton irradiation up to $1\times 10^{14}$~$n_{eq}/cm^{2}$. Electrical characterization via I-V, C-V, and $\alpha$ particle injection reveals an increase in threshold voltage and a 2 to 4 order of magnitude reduction in leakage current, while charge collection efficiency decreases by about 50\%. X-ray diffraction (XRD) and capacitance deep-level transient spectroscopy (C-DLTS) were employed to characterize the lattice structure and deep-level defects before and after irradiation. Deep-level defect characteristics were integrated into TCAD simulations to develop an electrical degradation model for SiC LGADs. A linear defect-flux relationship is established in the model, showing agreement with experimental results.