Overview of CMOS process and design options for image sensor dedicated to space applications

With the growth of huge volume markets (mobile phones, digital cameras…) CMOS technologies for image sensor improve significantly. New process flows appear in order to optimize some parameters such as quantum efficiency, dark current, and conversion gain. Space applications can of course benefit from these improvements. To illustrate this evolution, this paper reports results from three technologies that have been evaluated with test vehicles composed of several sub arrays designed with some space applications as target. These three technologies are CMOS standard, improved and sensor optimized process in 0.35µm generation. Measurements are focussed on quantum efficiency, dark current, conversion gain and noise. Other measurements such as Modulation Transfer Function (MTF) and crosstalk are depicted in [1]. A comparison between results has been done and three categories of CMOS process for image sensors have been listed. Radiation tolerance has been also studied for the CMOS improved process in the way of hardening the imager by design. Results at 4, 15, 25 and 50 krad prove a good ionizing dose radiation tolerance applying specific techniques

Open Data Platform for Knowledge Access in Plant Health Domain : VESPA Mining

Important data are locked in ancient literature. It would be uneconomic to produce these data again and today or to extract them without the help of text mining technologies. Vespa is a text mining project whose aim is to extract data on pest and crops interactions, to model and predict attacks on crops, and to reduce the use of pesticides. A few attempts proposed an agricultural information access. Another originality of our work is to parse documents with a dependency of the document architecture

The importance of sucrose synthase for AM symbiosis in maize, in pea and in Medicago

The arbuscular mycorrhiza (AM) is probably the most widespread symbiotic associations on earth, occurring in the roots of about 90 % of the land plant species. The fungal partners are soil-borne fungi of the order Glomales in the phylum of Glomero. The first AM fossils were dated to the Ordovician (505-434 million years ago), soon after the separation of the major groups of terrestrial fungi (around 600 million years ago) and at the time when the first land plants appeared. The existence of mycorrhizal fossils from very early epochs and its prevalence over all the different symbioses between plants and fungi indicate an important role of the AM symbiosis in the evolution of life on earth. They penetrate into the host cortical cells, invaginating the plasma membrane, and form highly branched structures, so-called arbuscules. This symbiosis is mutually beneficial since the fungus profits of the plant’s photoassimilates and the plant of an increased supply of mineral nutrients provided by the fungus. Glucose is probably the main carbon compound taken up by the fungus at the plant-fungal interface but little is known about carbon metabolism in the AM symbiosis. In particular, the complex mechanisms of the carbon allocation from the host-plant to the fungus have not been elucidated so far. In the last fifteen years, the AM symbiosis was more and more studied because of its widespread occurrence in the plant kingdom, including many agronomical interesting plants. The diversity of vesicular-arbuscular mycorrhizae in soils has been shown to be a determining factor for maintain of biodiversity and ecosystem functioning. The AM symbiosis shares similarities and common pathways with the Rhizobium-legume interaction, another symbiosis of great interest for grain and forage legumes used in agriculture. In this thesis, after a thorough review on the current knowledge of the molecular aspects of AM symbiosis, an untargeted approach to find genes induced in this symbiosis is described. A reverse transcription-PCR differential display (RT-PCR-DD) was carried out in order to identify plant genes involved in an AM symbiosis, using as a model Medicago truncatula colonized by the AM fungus, Glomus intraradices. A clone encoding a putative sucrose synthase (MtSucS2) was identified, and its regulation was studied with regard to mycorrhiza and nodulation. The expression of the newly discovered gene encoding MtSucS2 was compared to the expression of a nodule–enhanced sucrose synthase (MtSucS1) that had been isolated earlier from Medicago. Interestingly, the two sucrose synthases displayed an inverse expression pattern in mycorrhizal roots. Compared to control roots, MtSucs1 expression was lower in mycorrhizal roots, but MtSucS2 was 4 fold induced in 6 weeks old roots infected by Glomus intraradices. The expression of MtSucS2 was a higher in fruits, flowers and nodules than in leaves, roots and stems. The induction of MtSucS2 seems to be particularly important in “special sink tissues” while MtSucS1 is predominant in stems, flowers and nodulated roots. Based on an in-situ analysis of mRNA expression, it is likely that the induction of MtSucS2 is in fact much higher in the arbuscule-containing cells. The role of sucrose synthase in AM symbiosis was investigated with the use of pea and maize mutants deficient in the sucrose synthase. Maize and pea lines affected in genes coding for sucrose synthase showed wild-type growth and development with regards to the plant phenotype but did not display a normal development of the symbiosis. In a time-course experiment, a reduction of AM colonization was observed in maize mutant plants compared to the wild-type plants. In particular, vesicle formation was strongly reduced. The results highlight the importance of sucrose synthase(s) for a normal development of the AM symbiosis. A model is presented to illustrate the role of sucrose synthase in AM symbiosis

Generic radiation hardened photodiode layouts for deep submicron CMOS image sensor processes

Selected radiation hardened photodiode layouts, manufactured in a deep submicron CMOS Image Sensor technology, are irradiated by 60Co gamma-rays up to 2.2 Mrad(SiO2) and studied in order to identify the most efficient structures and the guidelines (recess distance, bias voltage) to follow to make them work efficiently in such technology. To do so, both photodiode arrays and active pixel sensors are used. After 2.2 Mrad(SiO2), the studied sensors are fully functional and most of the radiation hardened photodiodes exhibit radiation induced dark current values more than one order of magnitude lower than the standard photodiode

Displacement Damage Effects in Pinned Photodiode CMOS Image Sensors

This paper investigates the effects of displacement damage in Pinned Photodiode (PPD) CMOS Image Sensors (CIS) using proton and neutron irradiations. The DDD ranges from 12 TeV/g to ${1.2 times 10^{6}}$ TeV/g. Particle fluence up to $5 times 10^{14}$ n.cm $^{-2}$ is investigated to observe electro-optic degradation in harsh environments. The dark current is also investigated and it would appear that it is possible to use the dark current spectroscopy in PPD CIS. The dark current random telegraph signal is also observed and characterized using the maximum transition amplitude

Dynamic range optimisation of CMOS image sensors dedicated to space applications

Nowadays, CMOS image sensors are widely considered for space applications. Their performances have been significantly enhanced with the use of CIS (CMOS Image Sensor) processes in term of dark current, quantum efficiency and conversion gain. Dynamic Range (DR) remains an important parameter for a lot of applications. Most of the dynamic range limitation of CMOS image sensors comes from the pixel. During work performed in collaboration with EADS Astrium, SUPAERO/CIMI laboratory has studied different ways to improve dynamic range and test structures have been developed to perform analysis and characterisation. A first way to improve dynamic range will be described, consisting in improving the voltage swing at the pixel output. Test vehicles and process modifications made to improve voltage swing will be depicted. We have demonstrated a voltage swing improvement more than 30%. A second way to improve dynamic range is to reduce readout noise A new readout architecture has been developed to perform a correlated double sampling readout. Strong readout noise reduction will be demonstrated by measurements performed on our test vehicle. A third way to improve dynamic range is to control conversion gain value. Indeed, in 3 TMOS pixel structure, dynamic range is related to conversion gain through reset noise which is dependant of photodiode capacitance. Decrease and increase of conversion gain have been performed with different design techniques. A good control of the conversion gain will be demonstrated with variation in the range of 0.05 to 3 of initial conversion gain

Radiation damages in CMOS image sensors: testing and hardening challenges brought by deep sub-micrometer CIS processes

This paper presents a summary of the main results we observed after several years of study on irradiated custom imagers manufactured using 0,18 µm CMOS processes dedicated to imaging. These results are compared to irradiated commercial sensor test results provided by the Jet Propulsion Laboratory to enlighten the differences between standard and pinned photodiode behaviors. Several types of energetic particles have been used (gamma rays, X-rays, protons and neutrons) to irradiate the studied devices. Both total ionizing dose (TID) and displacement damage effects are reported. The most sensitive parameter is still the dark current but some quantum eficiency and MOSFET characteristics changes were also observed at higher dose than those of interest for space applications. In all these degradations, the trench isolations play an important role. The consequences on radiation testing for space applications and radiation-hardening-by-design techniques are also discussed

From Ideal Data Synchronization to Hybrid Forms of Interconnections: Architectures, Processes, and Data

With the emergence of new technologies, companies can organize their electronic data exchanges by implementing hybrid interorganizational information systems (IOS). This paper presents a new analytical framework by considering IOS as the product of interconnections between the parts of IS developed by connected firms to support a given interorganizational process. We focus on updating internal databases through data synchronization between a set of suppliers and a set of clients. From the literature, we built types of sending and receiving systems based on three variables; namely, shared data, structural linkages, and message interdependency. Analytically, we derived possibilities of interconnections between these sending and receiving systems with asymmetric characteristics. In a field study, we empirically investigated IOS built to support product information flows from suppliers’ to retailers’ internal, databases by considering how suppliers built their sending systems, how retailers built their receiving systems, and how their interconnections led to different forms of IOS. Interconnections occurring between systems with asymmetric characteristics show the existence of several hybrid forms of IOS, both in design and use. We finally explain that, even if companies can benefit from their use, hybrid forms are less efficient than are extreme forms, those that are the result of interconnections between systems with symmetric characteristics

Adoption Factors of Electronic Data Exchanges and Technologies to Improve Data Synchronization in BtoB Relationships: Are they similar?

Because of the emergence of technologies that allow more flexible interconnections, we propose to divide Interorganizational Information Systems (IOSs) adoption into two decision processes: electronic data exchanges adoption and technological choices. Indeed they are sequentially and in extreme case simultaneously related but independent since electronic data exchanges decision rarely imposes a technological choice. In this context, the research aims at distinguishing factors influencing the decision for a company to adopt electronic data exchanges with its partners and factors influencing the decision to adopt technologies supporting these electronic data exchanges. We investigate product information exchanges in the French consumer goods and retail industry through external catalogue, internal catalogue and Extranets. Analysis of 25 case studies allows us to conclude that it is relevant to distinguish these two decisions and the factors influencing each one