Radiation hardness of a large area CMOS active pixel sensor for bio-medical applications (original) (raw)
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An ionizing radiation-tolerant CMOS active pixel sensor (APS) image sensor test chip was designed employing the physical design techniques of enclosed geometry and -channel guard rings. The test chip was fabricated in a standard 0.35-m CMOS process that has a gate-oxide thickness of 7.0 nm. It was irradiated by a -ray source up to a total ionizing radiation dose level of approximately 30 Mrd (Si) and was still functional. The most pronounced effect was the increase of dark current, which was linear with total dose level. The rate of dark current increase was about 1 to 2 pA/cm 2 /Krd (Si), depending on the design of the pixel. The results demonstrate that CMOS APS image sensors can be designed to be ionizing radiation tolerant to total dose levels up to 30 Mrd (Si). The fabrication process is standard CMOS, yielding a significant cost advantage over specialized radiation hard processes.
Radiation hardness studies on CMOS monolithic pixel sensors
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2010
This paper presents irradiation studies performed on a CMOS monolithic pixel sensor prototype implementing different optimizations of the pixel cell aimed at a superior radiation tolerance. Irradiations with 200 keV electrons up to a total dose of 1.1 Mrad have been performed in view of the utilization of such a design in Transmission Electron Microscopy (TEM) applications. Comparative irradiations were performed with 29 MeV protons up to a 2 Mrad total dose and with 1-14 MeV neutrons up to fluences in excess of 10 13 n eq cm À 2 . Experimental results show an improved performance of pixels designed with Enclosed Layout Transistor (ELT) rules and an optimized layout of the charge collecting diodes.
Total dose effects on CMOS active pixel sensors
2000
Co 60 irradiations have been carried out on test structures for the development of CMOS Active Pixel Sensors (APS) that can be used in a radiation environment. The basic mechanisms that may cause failure are presented. Ionization induced damage effects such as field leakage currents and dark current increase are discussed in detail. Two different approaches to overcome these problems are considered and their advantages and disadvantages are compared. Total dose results are presented on a pixel that can tolerate more than 200 kGy(Si) (20 Mrad(Si)) from a Co 60 source.
Radiation tolerance of CMOS monolithic active pixel sensors with self-biased pixels
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2010
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.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2000
A new pixel readout prototype has been developed at CERN for high-energy physics applications. This full mixed mode circuit has been implemented in a commercial 0.5 lm CMOS technology. Its radiation tolerance has been enhanced by designing all NMOS transistors in enclosed geometry and introducing guardrings wherever necessary. The technique is explained and its e!ectiveness demonstrated on various irradiation measurements on individual transistors and on the prototype. Circuit performance started to degrade only after a total dose of 600 krad}1.7 Mrad depending on the type of radiation. 10 keV X-rays, 60Co gamma-rays, 6.5 MeV protons, and minimum ionizing particles were used. Implications of this layout approach on the circuit design and perspectives for even deeper submicron technologies are discussed. (
Latest Developments and Results of Radiation Tolerance CMOS Sensors with Small Collection Electrodes
Proceedings of the 29th International Workshop on Vertex Detectors (VERTEX2020), 2021
The development of radiation hard Depleted Monolithic Active Pixel Sensors (DMAPS) targets the replacement of hybrid pixel detectors to meet radiation hardness requirements of at least 1.5E16 1 MeV neq/cm2 for the HL-LHC and beyond. DMAPS were designed and tested in the TJ180nm TowerJazz CMOS imaging technology with small electrodes pixel designs. This technology reduces costs and provides granularity of 36.4x36.4µm2 with low power operation (1 µW / pixel), low noise of ENC <20e-, a small collection electrode (3 µm) and fast signal response within 25 ns bunch crossing. This contribution will present the latest developments after the MALTA and Mini-MALTA sensors. It will illustrate the improvements and results of the Czochralski substrate with a bigger depletion zone to improve efficiency. It will also present the plans for MALTA2, which will be produced in late 2020, with enlarged transistors to reduce noise and cascoded front-end corrected slow control to improve chip operation.
Total dose and displacement damage effects in a radiation-hardened CMOS APS
IEEE Transactions on Electron Devices, 2003
A 512 512 CMOS active pixel sensor (APS) was designed and fabricated in a standard 0.5-m technology. The radiation tolerance of the sensor has been evaluated with Co-60 and proton irradiation with proton energies ranging from 11.7 to 59 MeV. The most pronounced radiation effect is the increase of the dark current. However, the total ionizing dose-induced dark current increase is orders of magnitude smaller than in standard devices. It behaves logarithmically with dose and anneals at room temperature. The dark current increase due to proton displacement damage is explained in terms of the nonionizing energy loss of the protons. The fixed pattern noise does not increase with total ionizing dose. Responsivity changes are observed after Co-60 and proton irradiation, but a definitive cause has not yet been established.
Radiation Induced Effects in a Monolithic Active Pixel Sensor: The
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We have studied the effects of ionizing irradiation from a 60Co source and the effects of neutron irradiation on a Monolithic Active Pixel Sensor Chip (MIMOSA8). A previous report was devoted solely to the neutron-induced effects. We show that extended defects due to the neutron damage changes the distribution of the pixels pedestals. This is mainly due to the increase of the dark generation current due to the presence of deep traps in the depleted zones of the sensors. Alternatively, the exposure to ionizing irradiation increases the pedestals in a more homogeneous way, this coming from the generation of interface states at the Si/SiO2 interface supplemented by the presence of positively charged traps in the oxides. the sensors ’ leakage current is then increased. We discuss the results in view of increasing the radiation-hardness of the MAPS, bearing in mind that these chips were not designed with any rad-tol layout technique. 1- Permanent neutron effects at moderate clocking freq...