Techniques for the investigation of segmented sensors using the Two Photon Absorption -- Transient Current Technique

TL;DR

This paper presents advanced measurement techniques using TPA-TCT to analyze segmented silicon detectors, addressing challenges like laser beam effects and introducing methods for more accurate electric field characterization.

Contribution

It introduces new analysis methods for TPA-TCT measurements on segmented devices, including compensation for laser effects and a mirror technique for direct electric field measurement.

Findings

Effective compensation for laser beam clipping and reflection effects.

Successful implementation of the mirror technique for beneath metallisation measurements.

Enhanced accuracy in electric field analysis of segmented sensors.

Abstract

The Two Photon Absorption - Transient Current Technique (TPA-TCT) was used to investigate a silicon strip detector with illumination from the top. Measurement and analysis techniques for the TPA-TCT of segmented devices are presented and discussed using a passive strip CMOS detector as an example. The influence of laser beam clipping and reflection is shown and a method that allows to compensate these intensity related effects for the investigation of the electric field is introduced and successfully employed. Besides, the mirror technique is introduced, which exploits reflection at a metallised back side to enable the measurement directly below a top metallisation, while illuminating from the top.