Study of the Acceptor Removal Effect of LGAD

Abstract

This article presents a detailed investigation of the influence of carbon co-implantation on the radiation hardness of the low gain avalanche detectors (LGADs). The implantation and thermal annealing of carbon during LGAD fabrication could improve the device’s radiation hardness. As an attempt to explain the mechanism of the implanted carbon to suppress acceptor removal induced by neutron irradiation, the acceptor removal coefficients ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$c$ </tex-math></inline-formula> factors) of LGADs are modeled based on secondary ion mass spectrometry (SIMS), which is used to study carbon and boron distributions in critical regions of LGADs. The model is in good agreement with the radiation hardness measurement of both sensors fabricated by the Institute of High Energy Physics (IHEP) and by others, revealing the reliability of the model in predicting the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$c$ </tex-math></inline-formula> factor without irradiating the sensors but with only density profiles of carbon and boron. This model is pivotal to the design of the next version of IHEP LGAD aiming at reaching better anti-radiation performance.