# A new model for the TCAD simulation of the silicon damage by high fluence proton irradiation

## TL;DR

This paper introduces the Hamburg Penta Trap Model, a new TCAD simulation model that accurately describes silicon damage from high-fluence proton irradiation, aiding the development of radiation-hardened sensors for HL-LHC.

## Contribution

The paper develops and validates a novel bulk damage model for TCAD simulations that fits experimental data across a wide range of proton fluences, improving upon previous models.

## Key findings

- The Hamburg Penta Trap Model accurately reproduces I-V, C-V, and CCE measurements.
- The model is validated for fluences from 3×10^{14} to 1.3×10^{16} n_{eq}/cm^2.
- It provides a consistent description of silicon damage for high-fluence proton irradiation.

## Abstract

For the high-luminosity phase of the Large Hadron Collider (HL-LHC), at the expected position of the innermost pixel detector layer of the CMS and ATLAS experiments, the estimated equivalent neutron fluence after 3000 fb$^{-1}$ is 2$\cdot$10$^{16}$ n$_{eq}$/cm$^2$, and the IEL (Ionizing Energy Loss) dose in the SiO$_2$ 12 MGy. The optimisation of the pixel sensors and the understanding of their performance as a function of fluence and dose makes a radiation damage model for TCAD simulations, which describes the available experimental data, highly desirable. The currently available bulk-damage models are not able to describe simultaneously the measurements of dark current (I-V), capacitance-voltage (C-V) and charge collection efficiency (CCE) of pad diodes for fluences $\ge 1\cdot 10^{15}$ n$_{eq}$/cm$^2$. Therefore, for the development and validation of a new accurate bulk damage model we use I-V, C-V and CCE measurements on pad diodes available within the CMS-HPK campaign and data from samples irradiated recently with 24 GeV/c protons. For the determination of the radiation-induced damage parameters we utilise the "optimiser" of Synopsys TCAD, which allows the minimisation of the difference between the measured and simulated I-V, C-V and CCE. The outcome of this optimisation, the Hamburg Penta Trap Model (HPTM), provides a consistent and accurate description of the measurements of diodes irradiated with protons in the fluence range from 3$\cdot$10$^{14}$ n$_{eq}$/cm$^2$ to 1.3$\cdot$10$^{16}$ n$_{eq}$/cm$^2$.