TCAD Simulation of Two Photon Absorption -- Transient Current Technique measurements on Silicon Detectors and LGADs

TL;DR

This paper demonstrates that TCAD simulations can accurately reproduce TPA-TCT measurements on silicon detectors and LGADs, providing insights into internal processes and gain reduction mechanisms through detailed device modeling.

Contribution

The study validates TCAD simulations against experimental TPA-TCT data and successfully models gain reduction in LGADs due to excess charge carriers.

Findings

TCAD simulations match experimental TPA-TCT results

Simulated gain reduction in LGADs with increased charge density

Provides detailed understanding of carrier dynamics in silicon detectors

Abstract

Device simulation plays a crucial role in complementing experimental device characterisation by enabling deeper understanding of internal physical processes. However, for simulations to be trusted, experimental validation is essential to confirm the accuracy of the conclusions drawn.In the framework of semiconductor detector characterisation, one powerful tool for such validation is the Two Photon Absorption - Transient Current Technique (TPA-TCT), which allows for highly precise, three-dimensional spatially-resolved characterisation of semiconductor detectors. In this work, the TCAD framework Synopsys Sentaurus is used to simulate depth-resolved TPA-TCT data for both p-type pad detectors (PINs) and Low Gain Avalanche Detectors (LGADs). The simulated data are compared against experimentally measured TPA-TCT results. Through this comparison, it is demonstrated that TCAD simulations can reproduce the TPA-TCT measurements, providing valuable insights into the TPA-TCT itself. Another significant outcome of this study is the successful simulation of the gain reduction mechanism, which can be observed in LGADs with increasing densities of excess charge carriers. This effect is demonstrated in an p-type LGAD with a thickness of approximately 286 um. The results confirm the ability of TCAD to model the complex interaction between carrier dynamics and device gain.