Speaker
Description
The increasing radiation levels expected in future high-luminosity collider experiments demand robust predictive models for the design and optimisation of semiconductor particle detectors operating under extreme fluences (above $1 \cdot 10^{16}\,\mathrm{1\,MeV}\,n_{eq}/\mathrm{cm}^{2}$). Although TCAD-based modelling of radiation damage has evolved over the past two decades, a general-purpose model capable of reliably simulating the macroscopic effects of deep-level defects – particularly those induced at extreme fluences – is still lacking.
This work presents a TCAD simulation framework designed to reproduce Deep Level Transient Spectroscopy (DLTS) spectra and Arrhenius plots, enabling the refinement of trap characteristics – namely concentration, thermal activation energy, and electron and hole capture cross-section – to be implemented into numerical radiation damage models. In particular, the activities carried out so far include the reproduction of DLTS spectra of $C_{i}O_{i}$ (carbon-interstitial-oxygen-interstitial), $B_{i}O_{i}$ (boron-interstitial-oxygen-interstitial), $I_{2}O$ (di-self-interstitial-oxygen-interstitial), and $V_{2}(0/+)$ (single-positive charge state of the di-vacancy) defects, based on current (I-DLTS) and capacitance (C-DLTS) transient measurements in p-type silicon p-i-n diodes with different bulk resistivities ($250$ and $50\,\mathrm{Ωcm}$) at irradiation doses of $0.1$, $1$, $2$, and $5\,\mathrm{MGy}$, using the developed TCAD framework. In addition, numerical strategies (e.g. tuning of mathematical parameters) and specific workarounds – such as artificially increasing the charge-carrier generation rate – have been implemented to ensure convergence of the TCAD simulations of DLTS measurements down to cryogenic temperatures. To evaluate the reliability of the proposed framework, a benchmark procedure is defined, using both I- and C-DLTS measurements as reference data to validate the simulated defect response. This approach allows for a systematic assessment of the “effectiveness” of each trap in reproducing key device-level observables, such as leakage current, depletion voltage, and charge collection efficiency.
By bridging the gap between microscopic defect spectroscopy and macroscopic device simulation, the framework establishes the foundation for general-purpose TCAD models across semiconductor materials and fluence regimes, enhancing predictive power and guiding the design of radiation-hard detectors for future collider environments.