CMOS Monolithic Pixel Sensors based on the Column-Drain Architecture for the HL-LHC Upgrade

Abstract

Depleted Monolithic Active Pixel Sensors (DMAPS) constitute a promising low cost alternative for the outer layers of the ATLAS experiment Inner Tracker (ITk). Realizations in modern, high resistivity CMOS technologies enhance their radiation tolerance by achieving substantial depletion of the sensing volume. Two DMAPS prototypes that use the same "column-drain" readout architecture and are based on different sensor implementation concepts named LF-Monopix and TJ-Monopix have been developed for the High Luminosity upgrade of the Large Hardon Collider (HL-LHC). LF-Monopix was fabricated in the LFoundry 150 nm technology and features pixel size of $50x250\mu m^2$ and large collection electrode opted for high radiation tolerance. Detection efficiency up to 99\% has been measured after irradiation to $1\cdot 10^{15}{n}_{eq}/c{m}^2$. TJ-Monopix is a large scale $(1x2c{m}^2)$ prototype featuring pixels of $36x40\mu m^2$ size. It was fabricated in a novel TowerJazz 180 nm modified process that enables full depletion of the sensitive layer, while employing a small collection electrode that is less sensitive to crosstalk. The resulting small sensor capacitance ($<=3fF$) is exploited by a compact, low power front end optimized to meet the 25ns timing requirement. Measurement results demonstrate the sensor performance in terms of Equivalent Noise Charge (ENC) $\approx 11e^{-}$, threshold $\approx 300e^{-}$, threshold dispersion $\approx 30e^{-}$ and total power consumption lower than $120mW/c{m}^2$.

References in corpus (3)

• Depleted Fully Monolithic Active CMOS Pixel Sensors (DMAPS) in High Resistivity 150~nm Technology for LHC
• Depleted fully monolithic CMOS pixel detectors using a column based readout architecture for the ATLAS Inner Tracker upgrade
• Development of a Depleted Monolithic CMOS Sensor in a 150 nm CMOS Technology for the ATLAS Inner Tracker Upgrade

Cited by in corpus (4)

• Radiation hard DMAPS pixel sensors in 150nm CMOS technology for operation at LHC
• DMAPS Monopix developments in large and small electrode designs
• The Monopix chips: Depleted monolithic active pixel sensors with a column-drain read-out architecture for the ATLAS Inner Tracker upgrade
• Charge collection and efficiency measurements of the TJ-Monopix2 DMAPS in 180nm CMOS technology