Timing-Optimised 3D Silicon Sensor with Columnar Electrode Geometry.

Area of Science:

• High-energy physics instrumentation
• Semiconductor detector technology
• Radiation-hard sensor development

Background:

• 3D silicon sensors offer superior radiation hardness and timing resolution for particle physics applications.
• Columnar-type sensors are used in ATLAS (Inner B-Layer and Inner Tracking detectors).
• 3D trench sensors (INFN TimeSPOT project) achieve ~10 ps time resolution, even under high irradiation.

Purpose of the Study:

• To design a timing-optimized 3D silicon sensor combining columnar electrode fabrication robustness with trench sensor timing performance.
• To computationally compare the TimeSPOT 3D trench sensor with novel columnar electrode geometries.
• To explore parallel-oriented columnar designs that mimic trench electrode behavior.

Main Methods:

• Computational design and simulation of various 3D silicon sensor geometries.
• Comparison of columnar electrode-based designs against the established TimeSPOT trench sensor.
• Evaluation of different pixel sizes and configurations for timing optimization.

Main Results:

• Identified columnar electrode geometries that approximate the timing performance of trench-based sensors.
• Demonstrated the feasibility of achieving near-trench timing resolutions with robust columnar fabrication.
• Selected preliminary pixel geometries for upcoming 2025 production.

Conclusions:

• A new generation of 3D silicon sensors is being developed, balancing fabrication yield and advanced timing capabilities.
• The study provides a pathway to radiation-hard, fast-timing detectors for future high-luminosity experiments.
• Selected designs are ready for fabrication and further experimental validation.