No Arabic abstract
Depleted Monolithic Active Pixel Sensor (DMAPS) prototypes developed in the TowerJazz 180 nm CMOS imaging process have been designed in the context of the ATLAS upgrade Phase-II at the HL-LHC. The pixel sensors are characterized by a small collection electrode (3 $mu$m) to minimize capacitance, a small pixel size ($36.4times 36.4$ $mu$m), and are produced on high resistivity epitaxial p-type silicon. The design targets a radiation hardness of $1times10^{15}$ 1 MeV n$_{eq}$/cm$^{2}$, compatible with the outermost layer of the ATLAS ITK Pixel detector. This paper presents the results from characterization in particle beam tests of the Mini-MALTA prototype that implements a mask change or an additional implant to address the inefficiencies on the pixel edges. Results show full efficiency after a dose of $1times10^{15}$ 1 MeV n$_{eq}$/cm$^{2}$.
Monolithic Active Pixel Sensors (MAPS) have been developed since the late 1990s employing silicon substrate with a thin epitaxial layer in which deposited charge is collected by disordered diffusion rather than by drift in an electric field. As a consequence the signal is small and slow, and the radiation tolerance is below the requirements for LHC experiments by factors of 100 to 1000. We developed fully depleted (D)MAPS pixel sensors employing a 150 nm CMOS technology and using a high resistivity substrate as well as a high biasing voltage. The development has been carried out in three subsequent iterations, from prototypes to a large pixel matrix comprising a complete readout architecture suitable for LHC operation. Full CMOS electronics is embedded in large deep n-wells which at the same time serve as collection nodes (large electrode design). The devices have been intensively characterized before and after irradiation employing lab tests as well as particle beams. The devices can cope with particle rates seen by the innermost pixel detectors of the LHC pp-experiments or as seen by the outer pixel layers of the planned HL-LHC upgrade. They are radiation hard to particle fluences of at least $10^{15}~mathrm{n_{eq}/cm^2}$ and total ionization doses of at least 50 Mrad.
CMOS Monolithic Active Pixel Sensors (MAPS) are proposed as a technology for various vertex detectors in nuclear and particle physics. We discuss the mechanisms of ionizing radiation damage on MAPS hosting the the dead time free, so-called self bias pixel. Moreover, we discuss radiation hardened sensor designs which allow operating detectors after exposing them to irradiation doses above 1 Mrad
Pixel sensors using 8 CMOS processing technology have been designed and characterized offering the benefits of industrial sensor fabrication, including large wafers, high throughput and yield, as well as low cost. The pixel sensors are produced using a 150 nm CMOS technology offered by LFoundry in Avezzano. The technology provides multiple metal and polysilicon layers, as well as metal-insulator-metal capacitors that can be employed for AC-coupling and redistribution layers. Several prototypes were fabricated and are characterized with minimum ionizing particles before and after irradiation to fluences up to 1.1 $times$ 10$^{15}$ n$_{rm eq}$ cm$^{-2}$. The CMOS-fabricated sensors perform equally well as standard pixel sensors in terms of noise and hit detection efficiency. AC-coupled sensors even reach 100% hit efficiency in a 3.2 GeV electron beam before irradiation.
CMOS Pixel Sensors tend to become relevant for a growing spectrum of charged particle detection instruments. This comes mainly from their high granularity and low material budget. However, several potential applications require a higher read-out speed and radiation tolerance than those achieved with available devices based on a 0.35 micrometers feature size technology. This paper shows preliminary test results of new prototype sensors manufactured in a 0.18 micrometers process based on a high resistivity epitaxial layer of sizeable thickness. Grounded on these observed performances, we discuss a development strategy over the coming years to reach a full scale sensor matching the specifications of the upgraded version of the Inner Tracking System (ITS) of the ALICE experiment at CERN, for which a sensitive area of up to about 10 square meters may be equipped with pixel sensors.
A new generation of 3D silicon pixel detectors with a small pixel size of 50$times$50 and 25$times$100 $mu$m$^{2}$ is being developed for the HL-LHC tracker upgrades. The radiation hardness of such detectors was studied in beam tests after irradiation to HL-LHC fluences up to $1.4times10^{16}$ n$_{mathrm{eq}}$/cm$^2$. At this fluence, an operation voltage of only 100 V is needed to achieve 97% hit efficiency, with a power dissipation of 13 mW/cm$^2$ at -25$^{circ}$C, considerably lower than for previous 3D sensor generations and planar sensors.