Mortality of ultra-thin LGADs and PiN diodes from high energy deposition

Abstract

Low Gain Avalanche Diodes are prime candidates for high-resolution timing applications in High Energy Physics, Nuclear science, and several other fields. Operating these devices in high-radiation environments presents various hazards, including the risk of their permanent degradation or destruction caused by effects such as Single Event Burnout. Studies using minimum ionizing particles found a greatly reduced Single Event Burnout risk by operating below a bias voltage corresponding to an average electric field of 12 V/$\mu$m - however, as high energy particle colliders produce a wide energy spectrum of radiation, it is crucial to understand this phenomenon and other possible damage mechanisms at energy deposition levels greater than those of minimum ionizing particles. This was achieved by pre-irradiating LGADs and PiN diodes with active thicknesses of 20, 30, and 50 $\mu$m up to 1.5 $\times$ 10$^{15}$ $\mathrm{n_{eq}/cm^2}$, and exposing them to beams of protons and heavy ions (C, O, Fe, Au) at the BNL Tandem van de Graaff accelerator. Several mortality categories were observed, defined by different electrical and mechanical damage signatures. This furthers our understanding of permanent radiation damage of silicon devices, crucial towards mitigating Single Event Burnout and other damage mechanisms to safely operate future detectors.