The low gain avalanche detectors (LGADs) are thin sensors with fast charge collection which in combination with internal gain deliver an outstanding time resolution of about 30 ps. High collision rates and consequent large particle rates crossing the detectors at the upgraded Large Hadron Collider (LHC) in 2028 will lead to radiation damage and deteriorated performance of the LGADs. The main consequence of radiation damage is loss of gain layer doping (acceptor removal) which requires an increase of bias voltage to compensate for the loss of charge collection efficiency and consequently time resolution. The Institute of High Energy Physics (IHEP), Chinese Academy of Sciences (CAS) has developed a process based on the Institute of Microelectronics (IME), CAS capability to enrich the gain layer with carbon to reduce the acceptor removal effect by radiation. After 1 MeV neutron equivalent fluence of 2.5×1015 neq/cm2, which is the maximum fluence to which sensors will be exposed at ATLAS High Granularity Timing Detector (HGTD), the IHEP-IME second version (IHEP-IMEv2) 50 μm LGAD sensors already deliver adequate charge collection > 4 fC and time resolution < 50 ps at voltages < 400 V. The operation voltages of these 50 μm devices are well below those at which single event burnout may occur.
@article{arxiv.2205.05025,
title = {Design and testing of LGAD sensor with shallow carbon implantation},
author = {Kewei Wu and Xuewei Jia and Tao Yang and Mengzhao Li and Wei Wang and Mei Zhao and Zhijun Liang and Joao Guimaraes da Costa and Yunyun Fan and Han Cui and Alissa Howard and Gregor Kramberger and Xin Shi and Yuekun Heng and Yuhang Tan and Bo Liu and Yuan Feng and Shuqi Li and Mengran Li and Chengjun Yu and Xuan Yang and Mingjie Zhai and Gaobo Xu and Gangping Yan and Qionghua Zhai and Mingzheng Ding and Jun Luo and Huaxiang Yin and Junfeng Li},
journal= {arXiv preprint arXiv:2205.05025},
year = {2022}
}