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Öğe A 1-?W radiation-hard front-end in a 0.18-?m CMOS process for the MALTA2 monolithic sensor(IEEE-Institute Electrical Electronics Engineers Inc, 2022) Piro, F.; Allport, P.; Asensi, I.; Berdalovic, I.; Bortoletto, D.; Oyulmaz, Kaan YükselIn this article, a low-power, radiation-hard front-end circuit for monolithic pixel sensors, designed to meet the requirements of low noise and low pixel-to-pixel variability, the key features to achieve high detection efficiencies, is presented. The sensor features a small collection electrode to achieve a small capacitance (<5 fF) and allows full CMOS in-pixel circuitry. The circuit is implemented in the 180-nm CMOS imaging technology from the TowerJazz foundry and integrated into the MALTA2 chip, which is part of a development that targets the specifications of the outer pixel layer of the ATLAS Inner Tracker upgrade at the LHC. One of the main challenges for monolithic sensors is a radiation hardness up to 10(15) 1-MeV n(eq)/cm(2) non-ionizing energy loss (NIEL) and 80 Mrad total ionizing dose (TID) required for this application. Tests up to 3 . 10(15) 1-MeV n(eq)/cm(2) and 100 Mrad were performed on the MALTA2 sensor and front-end circuit, which still show good performance even after these levels of irradiation, promising for even more demanding applications such as the future experiments at the high-luminosity large hadron collider (HL-LHC).Öğe Future developments of radiation tolerant sensors based on the MALTA architecture(IOP Publishing Ltd, 2023) Dobrijevic, D.; Allport, P.; Asensi, I.; Berlea, D.; Bortoletto, D.; Oyulmaz, Kaan YükselThe planned MALTA3 DMAPS designed in the standard TowerJazz 180 nm imaging process will implement the numerous process modifications, as well as front-end changes in order to boost the charge collection efficiency after the targeted fluence of 1 x 1015 1 MeV neq/cm2. The effectiveness of these changes have been demonstrated with recent measurements of the full size MALTA2 chip. With the original MALTA concept being fully asynchronous, a small-scale MiniMALTA demonstrator chip has been developed with the intention of bridging the gap between the asynchronous pixel matrix, and the synchronous DAQ. This readout architecture will serve as a baseline for MALTA3, with focus on improved timing performance. The synchronization memory has been upgraded to allow clock speeds of up to 1.28 GHz, with the goal of achieving a sub-nanosecond on-chip timing resolution. The subsequent digital readout chain has been modified and will be discussed in the context of the overall sensor architecture.Öğe Latest developments and characterisation results of DMAPS in TowerJazz 180nm for High Luminosity LHC(Institute of Physics, 2022) De Acedo, L. Flores Sanz; Allport, P.; Tortajada, I. Asensi; Bortoletto, D.; Buttar, C.; Cardella, R.; Oyulmaz, Kaan YükselThe last couple of years have seen the development of Depleted Monolithic Active Pixel Sensors (DMAPS) fabricated in TowerJazz 180nm with a process modification to increase the radiation tolerance. While many of MAPS developments focus on low radiation environment, we have taken the development to high radiation environment like pp-experiments at High Luminosity LHC. DMAPS are a cost effective and lightweight alternative to state-of-the-art hybrid detectors if they can fulfil the given requirements for radiation hardness, signal response time and hit rate capability. The MALTA and Mini-MALTA sensors have shown excellent detection efficiency after irradiation to the life time dose expected at the outer layers of the ATLAS pixel tracker Upgrade. Our development focuses on providing large pixel matrixes with excellent time resolution (<2ns) and tracking. This publication will discuss characterisation results of the DMAPS devices with special focus on the new MALTA2 sensor and will show the path of future developments © Published under licence by IOP Publishing Ltd.Öğe MALTA monolithic pixel sensors in TowerJazz 180 nm technology(Elsevier, 2023) Sanchez, C. Solans; Allport, P.; Denizli, Haluk; Berlea, D. V.; Oyulmaz, Kaan Yüksel; Bortoletto, D.Depleted Monolithic Active Pixel Sensors are of highest interest at the HL-LHC and beyond for the replacement of the Pixel trackers in the outermost layers of experiments where the requirement on total area and cost effectiveness is much bigger. They aim to provide high granularity and low material budget over large surfaces with ease of integration. Our research focuses on MALTA, a radiation hard DMAPS with small collection electrode designed in TowerJazz 180 nm CMOS imaging technology and asynchronous read-out. Latest prototypes are radiation hard up to 2 x 1015 1 MeV neq/cm2 with a time resolution better than 2 ns.Öğe MALTA-Cz: a radiation hard full-size monolithic CMOS sensor with small electrodes on high-resistivity Czochralski substrate(IOP Publishing Ltd, 2023) Pernegger, H.; Allport, P.; Berlea, D. V.; Birman, A.; Bortoletto, D.; Denizli, HalukDepleted Monolithic Active Pixel Sensor (DMAPS) sensors developed in the Tower Semiconductor 180 nm CMOS imaging process have been designed in the context of the ATLAS ITk upgrade Phase-II at the HL-LHC and for future collider experiments. The "MALTA-Czochralski (MALTA-Cz)" full size DMAPS sensor has been developed with the goal to demonstrate a radiation hard, thin CMOS sensor with high granularity, high hit-rate capability, fast response time and superior radiation tolerance. The design targets radiation hardness of > 10(15) (1 MeV) n(eq)/cm(2) and 100 Mrad TID. The sensor shall operate as tracking sensor with a spatial resolution of approximate to 10 mu m and be able to cope with hit rates in excess of 100 MHz/cm(2) at the LHC bunch crossing frequency of 40 MHz. The 512 x 512 pixel sensor uses small collection electrodes (3.5 mu m) to minimize capacitance. The small pixel size (36.4 x 36.4 mu m(2)) provides high spatial resolution. Its asynchronous readout architecture is designed for high hit-rates and fast time response in triggered and trigger-less detector applications. The readout architecture is designed to stream all hit data to the multi-channel output which allows an off-sensor trigger formation and the use of hit-time information for event tagging.The sensor manufacturing has been optimised through process adaptation and special implant designs to allow the manufacturing of small electrode DMAPS on thick high-resistivity p-type Czochralski substrate. The special processing ensures excellent charge collection and charge particle detection efficiency even after a high level of radiation. Furthermore the special implant design and use of a Czochralski substrate improves the sensor's time resolution. This paper presents a summary of sensor design optimisation through process and implant choices and TCAD simulation to model the signal response. Beam and laboratory test results on unirradiated and irradiated sensors have shown excellent detection efficiency after a dose of 2 x 10(15) 1 MeV n(eq)/cm(2). The time resolution of the sensor is measured to be sigma = 2 ns.Öğe Mini-MALTA: radiation hard pixel designs for small-electrode monolithic CMOS sensors for the High Luminosity LHC(Iop Publishing Ltd, 2020) Dyndal, M.; Dao, V; Allport, P.; Tortajada, I. Asensi; Barbero, M.; Bhat, S.; Bortoletto, D.; Denizli, Haluk; Yorulmaz, Kaan YükselDepleted 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 (36.4 x 36.4 mu m(2)), and are produced on high resistivity epitaxial p-type silicon. The design targets a radiation hardness of 1 x 10(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 1 x 10(15) 1 MeV n(eq)/cm(2).Öğe Radiation hardness and timing performance in MALTA monolithic pixel sensors in TowerJazz 180 nm(IOP Publishing Ltd, 2022) Rijnbach, M. van; Allport, P.; Asensi, I.; Berdalovic, I.; Bortoletto, D.; Buttar, C.; Denizli, Haluk; Oyulmaz, Kaan YükselThe MALTA family of depleted monolithic pixel sensors produced in TowerJazz 180 nm CMOS technology target radiation hard applications for the HL-LHC and beyond. Several process modifications and front-end improvements have resulted in radiation hardness >10(15) 1 MeV n(eq)/cm(2) and time resolution below 2 ns, with uniform charge collection and efficiency across the pixel of size 36.4 x 36.4 mu m(2) with small collection electrode. This contribution will present the comparison of samples produced on high-resistivity epitaxial silicon with Czochralski substrates, before and after neutron irradiation, and results from MALTA2 with a new cascoded front-end flavour that further reduces the RTS noise.Öğe Timing performance of radiation hard MALTA monolithic pixel sensors(IOP Publishing Ltd, 2023) Gustavino, G.; Allport, P.; Asensi, I.; Berlea, D. V.; Bortoletto, D.; Denizli, Haluk; Oyulmaz, Kaan YükselThe MALTA family of Depleted Monolithic Active Pixel Sensor (DMAPS) produced in Tower 180 nm CMOS technology targets radiation hard applications for the HL-LHC and beyond. Several process modifications and front-end improvements have resulted in radiation hardness up to 2 x 10(15) 1 MeV n(eq)/cm(2) and time resolution below 2 ns, with uniform charge collection efficiency across the pixel of size 36.4 x 36.4 mu m(2) with a 3 mu m(2) electrode size. The MALTA2 demonstrator produced in 2021 on high-resistivity epitaxial silicon and on Czochralski substrates implements a new cascoded front-end that reduces the RTS noise and has a higher gain. This contribution shows results from MALTA2 on timing resolution at the nanosecond level from the CERN SPS test-beam campaign of 2021.
