Characterization of a depleted monolithic pixel sensors in 150 nm CMOS technology for the ATLAS Inner Tracker upgrade

TL;DR

This paper introduces a new monolithic pixel sensor prototype in 150 nm CMOS technology designed for the ATLAS Inner Tracker upgrade, demonstrating its potential for high-energy physics applications with lower cost and material use.

Contribution

It presents the design and characterization of LF-Monopix, a fully monolithic sensor prototype for HL-LHC, showcasing its feasibility and performance in a high-radiation environment.

Findings

Successful characterization of pre-amplifier and discriminator variants

Demonstrated sensor operation with external injection and x-ray sources

Lower cost and material budget compared to hybrid sensors

Abstract

This work presents a depleted monolithic active pixel sensor (DMAPS) prototype manufactured in the LFoundry 150\,nm CMOS process. DMAPS exploit high voltage and/or high resistivity inclusion of modern CMOS technologies to achieve substantial depletion in the sensing volume. The described device, named LF-Monopix, was designed as a proof of concept of a fully monolithic sensor capable of operating in the environment of outer layers of the ATLAS Inner Tracker upgrade in 2025 for the High Luminosity Large Hadron Collider (HL-LHC). This type of devices has a lower production cost and lower material budget compared to presently used hybrid designs. In this work, the chip architecture will be described followed by the characterization of the different pre-amplifier and discriminator flavors with an external injection signal and an iron source (5.9\,keV x-rays).