Jean-Michel Portal

Bio: Jean-Michel Portal is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Resistive random-access memory & Artificial neural network. The author has an hindex of 25, co-authored 136 publications receiving 2047 citations. Previous affiliations of Jean-Michel Portal include Alternatives & Aix-Marseille University.

Bipolar ReRAM Based non-volatile flip-flops for low-power architectures

Abstract: Resistive Random Access Memories (ReRAMs) fabricated in the back-end-of-line are a promising breakthrough for including permanent retention mechanisms in embedded systems. This low-cost solution opens the way to advanced power management schemes. In this paper, we propose novel design architecture of a non-volatile flip-flop based on Bipolar ReRAMs (Bi-RNVFF). Compared to state-of-the-art Data-Retention flip-flop (with Balloon latch), the proposed design is 25% smaller due to 6T structure compared to the 8T structure of Data-Retention flip-flop. Moreover, being non-volatile, the proposed architecture exhibits a zero leakage compared to a Data-Retention Flip-Flop, which consumes ∼3.2µW in sleep mode (leakage) for a 10K Flip-Flop design implemented in 22nm FDSOI technology. Our simulation results show that Bi-RNVFF is a true alternative for future “Power-on, Power-off” application adding Non-Volatility without significant burdening of the existing architectures.

SRAM-Based FPGAs: Testing the Embedded RAM Modules

Abstract: This paper addresses the problem of testing the RAM mode of the LUT/RAM modules of configurable SRAM-based Field Programmable Gate Arrays (FPGAs) using a minimum number of test configurations. A model of architecture for the LUT/RAM module with N inputs and 2N memory cells is proposed taking into account the LUT and RAM modes. Targeting the RAM mode, we demonstrate that a unique test configuration is required for a single module. The problem is shown equivalent to the test of a classical SRAM circuit allowing to use existing algorithms such as the March tests. We also propose a unique test configuration called ‘pseudo shift register’ for an m × m array of modules. In the proposed configuration, the circuit operates as a shift register and an adapted version of the MATS++ algorithm called ‘shifted MATS++’ is described.

In-Memory and Error-Immune Differential RRAM Implementation of Binarized Deep Neural Networks.

Abstract: RRAM-based in-Memory Computing is an exciting road for implementing highly energy efficient neural networks. This vision is however challenged by RRAM variability, as the efficient implementation of in-memory computing does not allow error correction. In this work, we fabricated and tested a differential HfO2-based memory structure and its associated sense circuitry, which are ideal for in-memory computing. For the first time, we show that our approach achieves the same reliability benefits as error correction, but without any CMOS overhead. We show, also for the first time, that it can naturally implement Binarized Deep Neural Networks, a very recent development of Artificial Intelligence, with extreme energy efficiency, and that the system is fully satisfactory for image recognition applications. Finally, we evidence how the extra reliability provided by the differential memory allows programming the devices in low voltage conditions, where they feature high endurance of billions of cycles.

La pollution de l'eau par les produits phytosanitaires: état et origine

Abstract: Les campagnes d'analyse des eaux de surface ou souterraines utilisees comme ressource en eau potable montrent frequemment une pollution par les produits phytosanitaires au-dela de la norme UE. Cette situation est en partie due a une agriculture intensive, au non respect des bonnes pratiques agricoles, aux usages non agricoles des pesticides mais egalement a l'existence de sites particulierement vulnerables (reseau hydrologique dense et diffus, relief accidente, sols filtrants ou fissures, nappes peu profondes). Son evaluation peut etre realisee a differentes echelles. Cependant, seule l'etude regionale apparait comme satisfaisante. En effet, elle permet de mieux cibler les produits a rechercher, les dates d'echantillonnage et le type d'eau a surveiller en fonction des ressources en eau potable. Les pesticides mis en cause dans la pollution de l'eau en France sont actuellement peu nombreux: atrazine, simazine, lindane, carbofuran, phenylurees. Mais cette liste peut se diversifier en prenant en compte la specificite de l'agriculture locale par reduction de l'echelle d'investigation ou par la prise en compte des produits de degradation des pesticides utilises (deethylatrazine). Pour les eaux de surface, la pollution peut etre tres elevee mais de courte duree. Elle est etroitement liee aux possibilites de transport des pesticides par ruissellement et a l'effet de dilution par les eaux provenant de secteurs non traites. En revanche, pour les eaux souterraines, la pollution est plus discrete mais elle peut etre permanente. Elle est regulee par le processus de lessivage, lui-meme lie a la disponibilite du produit et a la dynamique de l'eau. Dans le cas ou le pesticide est a la fois persistant et quelque peu mobile, il peut y avoir un stockage du produit dans le sol, qui entretient la pollution des eaux souterraines.

Emerging memories: resistive switching mechanisms and current status.

Abstract: The resistance switching behaviour of several materials has recently attracted considerable attention for its application in non-volatile memory (NVM) devices, popularly described as resistive random access memories (RRAMs). RRAM is a type of NVM that uses a material(s) that changes the resistance when a voltage is applied. Resistive switching phenomena have been observed in many oxides: (i) binary transition metal oxides (TMOs), e.g. TiO(2), Cr(2)O(3), FeO(x) and NiO; (ii) perovskite-type complex TMOs that are variously functional, paraelectric, ferroelectric, multiferroic and magnetic, e.g. (Ba,Sr)TiO(3), Pb(Zr(x) Ti(1-x))O(3), BiFeO(3) and Pr(x)Ca(1-x)MnO(3); (iii) large band gap high-k dielectrics, e.g. Al(2)O(3) and Gd(2)O(3); (iv) graphene oxides. In the non-oxide category, higher chalcogenides are front runners, e.g. In(2)Se(3) and In(2)Te(3). Hence, the number of materials showing this technologically interesting behaviour for information storage is enormous. Resistive switching in these materials can form the basis for the next generation of NVM, i.e. RRAM, when current semiconductor memory technology reaches its limit in terms of density. RRAMs may be the high-density and low-cost NVMs of the future. A review on this topic is of importance to focus concentration on the most promising materials to accelerate application into the semiconductor industry. This review is a small effort to realize the ambitious goal of RRAMs. Its basic focus is on resistive switching in various materials with particular emphasis on binary TMOs. It also addresses the current understanding of resistive switching behaviour. Moreover, a brief comparison between RRAMs and memristors is included. The review ends with the current status of RRAMs in terms of stability, scalability and switching speed, which are three important aspects of integration onto semiconductors.

Neuromorphic computing using non-volatile memory

Abstract: Dense crossbar arrays of non-volatile memory (NVM) devices represent one possible path for implementing massively-parallel and highly energy-efficient neuromorphic computing systems. We first revie...

Monitoring of environmental exposure to polycyclic aromatic hydrocarbons: a review

Abstract: Polycyclic aromatic hydrocarbons (PAHs) are a large group of organic compounds with two or more fused aromatic rings. They have a relatively low solubility in water, but are highly lipophilic. Most of the PAHs with low vapour pressure in the air are adsorbed on particles. When dissolved in water or adsorbed on particulate matter, PAHs can undergo photodecomposition when exposed to ultraviolet light from solar radiation. In the atmosphere, PAHs can react with pollutants such as ozone, nitrogen oxides and sulfur dioxide, yielding diones, nitro- and dinitro-PAHs, and sulfonic acids, respectively. PAHs may also be degraded by some microorganisms in the soil. PAHs are widespread environmental contaminants resulting from incomplete combustion of organic materials. The occurrence is largely a result of anthropogenic emissions such as fossil fuel-burning, motor vehicle, waste incinerator, oil refining, coke and asphalt production, and aluminum production, etc. PAHs have received increased attention in recent years in air pollution studies because some of these compounds are highly carcinogenic or mutagenic. Eight PAHs (Car-PAHs) typically considered as possible carcinogens are: benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene (B(a)P), dibenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene and benzo(g,h,i)perylene. In particular, benzo(a)pyrene has been identified as being highly carcinogenic. The US Environmental Protection Agency (EPA) has promulgated 16 unsubstituted PAHs (EPA-PAH) as priority pollutants. Thus, exposure assessments of PAHs in the developing world are important. The scope of this review will be to give an overview of PAH concentrations in various environmental samples and to discuss the advantages and limitations of applying these parameters in the assessment of environmental risks in ecosystems and human health. As it well known, there is an increasing trend to use the behavior of pollutants (i.e. bioaccumulation) as well as pollution-induced biological and biochemical effects on human organisms to evaluate or predict the impact of chemicals on ecosystems. Emphasis in this review will, therefore, be placed on the use of bioaccumulation and biomarker responses in air, soil, water and food, as monitoring tools for the assessment of the risks and hazards of PAH concentrations for the ecosystem, as well as on its limitations.