Characterisation of analogue MAPS fabricated in 65 nm technology for the ALICE ITS3

TL;DR

This paper characterizes 65 nm MAPS technology for the ALICE ITS3 vertex detector, demonstrating high efficiency and spatial resolution suitable for high-energy physics experiments and future collider applications.

Contribution

It provides a detailed analysis of analogue MAPS fabricated in 65 nm technology, including charge collection, spatial resolution, and efficiency under irradiation, supporting their use in high-energy physics detectors.

Findings

Achieved spatial resolution better than 3 μm with 10 μm pitch.

Over 99% efficiency in moderate irradiation conditions.

Charge sharing and collection are optimized for the technology.

Abstract

The ALICE ITS3 project foresees the use of ultra-light MAPS, developed in the 65 nm imaging process, for the vertex detector in the ALICE experiment at the LHC to drastically improve the vertexing performance. This new development, initiated by an international consortium of the ALICE ITS3 collaboration and the CERN EP R&D project, enhances the overall MAPS performance. Small-scale prototypes are designed to study the analogue properties of the TPSCo 65 nm technology and compare the charge collection performance in different processes, pitches, pixel geometries, and irradiation levels. Recent results from lab and test-beam characterisation detailing the efficiency and the spatial resolution of the APTS with different pixel geometries and pitches satisfy the ALICE ITS3 requirements. A quantitative evolution of the charge collection and sharing among pixels is evident in the CE-65 with different in-pixel readouts. Attaining a spatial resolution better than 3 $\mu$m with a 10 $\mu$m pitch and over 99% efficiency in the moderate irradiation environment of ALICE also supports the viability of using 65 nm MAPS for FCC-ee vertex detectors.