Low Gain Avalanche Detectors with Good Time Resolution Developed by IHEP and IME for ATLAS HGTD project

TL;DR

This paper presents the development, simulation, and testing of 50um thick LGAD sensors with improved time resolution and gain characteristics, suitable for the ATLAS HGTD project, demonstrating promising performance before irradiation.

Contribution

The paper introduces new LGAD sensors with optimized gain layer doses and production processes, achieving better time resolution and charge collection for high-energy physics applications.

Findings

Time resolution better than 35ps at high voltage

Collected charge exceeds 15fC before irradiation

Higher gain layer dose correlates with lower breakdown voltage

Abstract

This paper shows the simulation and test results of 50um thick Low Gain Avalanche Detectors (LGAD) sensors designed by the Institute of High Energy Physics (IHEP) and fabricated by the Institute of Microelectronics of the Chinese Academy of Sciences (IME). Three wafers have been produced with four different gain layer implant doses each. Different production processes, including variation in the n++ layer implant energy and carbon co-implantation were used. Test results show that the IHEP-IME sensors with the higher dose of gain layer have lower breakdown voltages and higher gain layer voltages from capacitance-voltage properties, which are consistent with the TCAD simulation. Beta test results show that the time resolution of IHEP-IME sensors is better than 35ps when operated at high voltage and the collected charges of IHEP-IME sensors are larger than 15fC before irradiation, which fulfill the required specifications of sensors before irradiations for the ATLAS HGTD project.