In this paper, we report on the radiation resistance of 50-micron thick LGAD detectors manufactured at the Fondazione Bruno Kessler employing several different doping combinations of the gain layer. LGAD detectors with gain layer doping of Boron, Boron low-diffusion, Gallium, Carbonated Boron and Carbonated Gallium have been designed and successfully produced. These sensors have been exposed to neutron fluences up to ϕn∼3⋅1016n/cm2 and to proton fluences up to ϕp∼9⋅1015p/cm2 to test their radiation resistance. The experimental results show that Gallium-doped LGADs are more heavily affected by initial acceptor removal than Boron-doped LGAD, while the presence of Carbon reduces initial acceptor removal both for Gallium and Boron doping. Boron low-diffusion shows a higher radiation resistance than that of standard Boron implant, indicating a dependence of the initial acceptor removal mechanism upon the implant width. This study also demonstrates that proton irradiation is at least twice more effective in producing initial acceptor removal, making proton irradiation far more damaging than neutron irradiation.
@article{arxiv.1802.01745,
title = {Radiation resistant LGAD design},
author = {M. Ferrero and R. Arcidiacono and M. Barozzi and M. Boscardin and N. Cartiglia and G. F. Dalla Betta and Z. Galloway and M. Mandurrino and S. Mazza and G. Paternoster and F. Ficorella and L. Pancheri and H-F W. Sadrozinski and V. Sola and A. Staiano and A. Seiden and F. Siviero and M. Tornago and Y. Zhao},
journal= {arXiv preprint arXiv:1802.01745},
year = {2019}
}