Impact of Proton Irradiation on 4H-SiC Low Gain Avalanche Detectors (LGADs)

TL;DR

This study investigates how proton irradiation affects 4H-SiC LGADs, revealing performance degradation but also demonstrating their potential for high-energy physics in extreme environments.

Contribution

It provides the first detailed analysis of proton irradiation effects on 4H-SiC LGADs, highlighting their resilience and potential for future applications.

Findings

Gain and rectification decrease with proton fluence

Capacitance and OFF-state current reduction indicate gain layer compensation

Measurable signal persists after irradiation

Abstract

Silicon carbide (SiC) particle detectors have the potential to provide time resolutions and robust performance in extreme environments which exceed that of silicon detectors. In this work 4H-SiC low gain avalanche detectors (LGADs) and complementary PiN diodes were irradiated with 2.5 GeV protons at fluences up to 3.33$\times$10$^{14}$ p/cm$^2$. The electrostatic performance of both irradiated and non-irradiated devices was evaluated using current-voltage (I-V) and capacitance-voltage (C-V) measurements. Moreover, charge collection measurements using $\alpha$ particles were also conducted. SiC LGADs displayed a loss in rectification and gain with increasing proton fluence. Additionally, the reduction in capacitance and OFF-state current pointed to compensation of the gain layer as a gain reducing mechanism. The introduction of radiation induced defects also hinders carrier acceleration reducing impact ionization, leading to further gain reduction. However, despite the reduction in device performance, the demonstration of a measurable signal and gain after irradiation points to the potential of SiC LGAD detectors for future high energy physics applications.