Abstract
Recent advancements in Monolithic Active Pixel Sensors (MAPS) demonstrated the ability to operate in high radiation environments of up to multiple kGy’s, which increased their appeal as ...sensors for high-energy physics detectors. The most recent example in such application is the new ALICE inner tracking system, entirely instrumented with CMOS MAPS, that covers an area of about 10 m
2
. However, the full potential of such devices has not yet been fully exploited, especially in respect of the size of the active area, power consumption, and timing capabilities.
The ARCADIA project is developing Fully Depleted (FD) MAPS with an innovative sensor design, that uses a proprietary processing of the backside to improve the charge collection efficiency and timing over a wide range of operational and environmental conditions. The innovative sensor design targets very low power consumption, of the order of 20 mW cm
−2
at 100 MHz cm
−2
hit flux, to enable air-cooled operations of the sensors. Another key design parameter is the ability to further reduce the power regime of the sensor, down to 5 mW cm
−2
or better, for low hit rates like e.g. expected in space experiments. In this contribution, we present a comparison between the detector characteristics predicted with Technology Computer Aided Design (TCAD) simulations and the ones measured experimentally. The comparison focuses on the current-voltage (IV) and capacitance-voltage (CV) characteristics, as well as noise estimated from in-pixel capacitances of passive/active pixel matrices. In view of the targeted applications of this technology, an emphasis is set on the modeling of X-ray induced radiation damage at the Si-SiO
2
interface and the impact on the in-pixel sensor capacitance. The so-called new Perugia model has been used in the simulations to predict the sensor performance after total ionizing doses of up to 10 Mrad.
Abstract
The ARCADIA collaboration is developing fully-depleted (FD) Monolithic Active Pixel Sensors (MAPS) in a 110 nm CMOS process in collaboration with LFoundry. The sensor design incorporates an ...n+ collection node within a n-type epi-layer on top of a high-resistivity n-type substrate and p+ backside. Thus, the pn-junction sits on the backside and through an applied backside bias, the full substrate gets depleted. The targeted applications of this technology range from future high energy physics experiments to space applications, and medical and industrial scanners. Together, these applications set the minimum requirements on the detector: data collection at hit rates of (10–100) MHz/cm
2
, full signal processing within (1–10) μs, maximum power consumption (5–20) mW/cm
2
and radiation tolerances of up to 3.4 Mrad or 6.2 × 10
12
1 MeV neutron equivalent fluence. In order to proof the performance of the technology, a demonstrator chip of 512 × 512 pixels with 25 μm pitch was designed and fabricated in a first engineering run in 2021, together with additional test structures of pixel and strip arrays with different pitches and sensor geometries. The production run has produced functional passive and active pixel matrices. Earlier studies have shown that positive oxide charges and traps at the Si-SiO
2
interface, introduced by ionising radiation, affect the depletion region around the collection electrode, increasing the pixel capacitance. By varying the gap size between collection node and pwells, the geometry can be optimised to keep the capacitance low also after irradiation. To study the performance after irradiation, of the optimised diode designs, the passive pixel matrices were irradiated with doses up to 10 Mrad (SiO
2
) using a X-ray tube with a Tungsten anode. The measurements are complemented by TCAD simulations. The maximum capacitance increase after irradiation was found to reach 6 and 12 fF/pixel for pixel pitches of 25 and 50 μm, respectively. The relative capacitance increase after irradiation has hereby been found to reach up to 250% after a dose of 10 Mrad.
Abstract
The development of novel Monolithic Active Pixel Sensor (MAPS) technologies has been pursued by several collaborations in the last two decades. The ARCADIA project aims to design fully ...depleted MAPS for medical, space, HEP and X-ray detection applications, that can be produced with a commercial 110 nm CMOS production process. Among the test structures of the first two engineering runs of the project, passive pixel arrays with different pitches and layouts were included. The main characteristics of the produced devices in terms of dark current, depletion voltage, punch through current and pixel capacitance have been evaluated from IV and CV characteristics of the pixel arrays. Groups of four samples have been extracted from as many different positions within each wafer and electrically characterized to obtain information on the variability in the pixel operating voltage range and in the pixel dark current, reflecting variations related to the employed production process. The experimental data demonstrated a good uniformity in the considered parameters for different sample positions within the produced wafers, as well as for samples extracted from different wafers with the same substrate type.
Abstract Thanks to their advantages in terms of easiness of manufacturing and reduced production costs, Monolithic Active Pixel Sensors (MAPS) represent an appealing solution for radiation imaging ...applications, which require to cover large areas with pixelated detectors. In the next upgrade of the ALICE detector, that will have to deal with the higher event rate resulting from the planned increase in the LHC luminosity, it is foreseen to include two additional sensor layers to perform Time of Flight (ToF) measurements. Trying to reach the challenging timing resolution required by the ALICE ToF layers, an internal gain layer has been included in the test structures of the third engineering run of the ARCADIA project to improve the timing performance of this MAPS technology. In the paper we will present an overview of the main results obtained from the electrical and the dynamic characterization of the fabricated devices, which have been compared with the behavior expected from the preliminary TCAD simulations carried out in the design phase. The experimental results confirmed the feasibility of embedding a gain layer in the ARCADIA 110 nm CMOS technology to develop monolithic LGADs.
Abstract In this paper we report on a set of characterisations carried out on the first monolithic LGAD prototype integrated in a customised 110 nm CMOS process having a depleted active volume ...thickness of 48 μm. This prototype is formed by a pixel array where each pixel has a total size of 100 μm× 250 μm and includes a high-speed front-end amplifier. After describing the sensor and the electronics architecture, both laboratory and in-beam measurements are reported and described. Optical characterisations performed with an IR pulsed laser setup have shown a sensor internal gain of about 2.5. With the same experimental setup, the electronic jitter was found to be between 50 ps and 150 ps, depending on the signal amplitude. Moreover, the analysis of a test beam performed at the Proton Synchrotron (PS) T10 facility of CERN with 10 GeV/c protons and pions indicated that the overall detector time resolution is in the range of 234 ps to 244 ps. Further TCAD investigations, based on the doping profile extracted from C(V) measurements, confirmed the multiplication gain measured on the test devices. Finally, TCAD simulations were used to tune the future doping concentration of the gain layer implant, targeting sensors with a higher avalanche gain. This adjustment is expected to enhance the timing performance of the sensors of the future productions, in order to cope with the high event rate expected in most of the near future high-energy and high-luminosity physics experiments, where the time resolution will be essential to disentangle overlapping events and it will also be crucial for Particle IDentification (PID).
Fully depleted monolithic active pixel sensors (FD-MAPSs) represent a state-of-the-art detector technology and profit from a low material budget and cost for high-energy physics experiments and other ...fields of research like medical imaging and astro-particle physics. Compared to the MAPS currently in use, fully depleted pixel sensors have the advantage of charge collection by drift, which enables a fast and uniform response overall to the pixel matrix. The functionality of these devices has been shown in previous proof-of-concept productions. In this article, we describe the optimization of the test pixel designs that will be implemented in the first engineering run of the demonstrator chip of the ARCADIA project. These optimization procedures include radiation damage models that have been employed in Technology Computer Aided Design simulations to predict the sensors’ behavior in different working environments.
Monolithic Active Pixel Sensors (MAPS) are a promising technology that provides large sensitive areas at potentially low power consumption and low material budget. The ARCADIA project is developing ...Fully Depleted MAPS (FD-MAPS) with an innovative sensor design, that uses a backside bias to improve charge collection efficiency and timing over a wide range of operational and environmental conditions. The ARCADIA collaboration has produced a large set of prototypes in the first two engineering runs, with the main design consisting of a 512 × 512 pixel matrix with 25μm pixel pitch and other smaller active sensor arrays. Test structures of pixel matrices with pixel pitches ranging from 10 to 50μm and total thicknesses of 50 to 200μm have also been included, to ease the characterization of the sensors independently from integrated electronics. We give an overview of the status of the project and then focus on the characterization of the passive pixel matrices which include Capacitance–Voltage (CV) and Current–Voltage (IV), as well as Transient Current Technique (TCT) measurements with a red and an infrared laser. We could confirm a single pixel capacitance below 5fF for pixels with 25μm pitch, and a 90% charge collection of MIP-like charge depositions within 12ns in 100μm active thickness. These results are complemented and supported by Technology Computer Aided Design (TCAD) simulations.
In this paper we report on a set of characterisations carried out on the first monolithic LGAD prototype integrated in a customised 110 nm CMOS process having a depleted active volume thickness of 48 ...\(\mu\)m. This prototype is formed by a pixel array where each pixel has a total size of 100 \(\mu\)m \(\times\) 250 \(\mu\)m and includes a high-speed front-end amplifier. After describing the sensor and the electronics architecture, both laboratory and in-beam measurements are reported and described. Optical characterisations performed with an IR pulsed laser setup have shown a sensor internal gain of about 2.5. With the same experimental setup, the electronic jitter was found to be between 50 ps and 150 ps, depending on the signal amplitude. Moreover, the analysis of a test beam performed at the Proton Synchrotron (PS) T10 facility of CERN with 10 GeV/c protons and pions indicated that the overall detector time resolution is in the range of 234 ps to 244 ps. Further TCAD investigations, based on the doping profile extracted from \(C(V)\) measurements, confirmed the multiplication gain measured on the test devices. Finally, TCAD simulations were used to tune the future doping concentration of the gain layer implant, targeting sensors with a higher avalanche gain. This adjustment is expected to enhance the timing performance of the sensors of the future productions, in order to cope with the high event rate expected in most of the near future high-energy and high-luminosity physics experiments, where the time resolution will be essential to disentangle overlapping events and it will also be crucial for Particle IDentification (PID).
Heterotrophic nanoflagellates (HNANs) play a pivotal role as consumers of picoplankton, remineralizers and carbon vectors, yet knowledge on how prey quantity and quality affect HNAN physiology ...remains limited. In a series of grazing experiments using an uncharacterized member of the HNAN assemblage, we found that growth (μ) and ingestion rate (IR) varied when offering heterotrophic bacteria (HB),
Synechococcus
spp. (
Syn
),
Ostreococcus lucimarinus
(
Ost
) or a combination of all 3 prey types. Highest average μ rates (1.8 d
-1
) were detected on HB at densities of ~10
6
cells ml
-1
and maximum IR on
Syn
(485 pg C d
-1
) at ~10
6
cells ml
-1
. Independent of prey type, flagellate μ increased with IR up to ~50 pg C d
-1
. A relatively low P-content in
Ost
was linked to shifts in C:N:P ratios of the HNAN in the single-prey experiment and when
Ost
was offered as part of the mixed assemblage. Presented with a mixed diet, the highest contribution to daily C intake came from
Ost
with 50%, followed by HB with 46% and
Syn
with only 4%. C-based gross growth efficiencies (GGEs) were higher when feeding on HB and mixed prey, compared to both picophototrophs, while N- and P-based GGEs in mixed prey treatments markedly exceeded those when feeding on any single prey. The findings in this study corroborate the importance of investigating the biogeochemical role of HNANs in relation to prey availability and quality to refine estimates of energy transfer within the microbial loop.
The evolution of forearc and backarc domains is usually treated separately, as they are separated by a volcanic arc. We analyse their spatial and temporal relationships in the Tyrrhenian subduction ...system, using seismic profiles and numerical modelling. A volcanic arc, which included the Marsili volcano, was involved in arc-rifting during the Pliocene. This process led to the formation of an oceanic backarc basin (~ 1.8 Ma) to the west of the Marsili volcano. The eastern region corresponded to the forearc domain, floored by serpentinised mantle. Here, a new volcanic arc formed at ~ 1 Ma, marking the onset of the forearc-rifting. This work highlights that fluids and melts induce weakening of the volcanic arc region and drive the arc-rifting that led to the backarc basin formation. Later, the slab rollback causes the trench-ward migration of volcanism that led to the forearc- rifting under the control of fluids released from the downgoing plate.
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