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.

Analyzing bridging faults impact on EEPROM cell array

Abstract: The objective of this paper is to present a specific EEPROM functional fault model related to the impact of bridging faults in the array of cells. Moreover, the evolution of these functional faults throughout the useful life of the memory is established. In this aim, a hierarchical overview from the array structure down to the floating gate transistor simulation model is given. A set of bridging faults is defined with their corresponding stimuli. Finally, a representative simulation example is detailed.

Resistive and Spintronic RAMs: Device, Simulation, and Applications

Abstract: The emergence of non-volatile random access memory technologies, such as resistive and spintronic RAMs are triggering intense interdisciplinary activity. These technologies have the potential of providing many benefits, such as energy efficiency, high integration density, CMOS-compatibility, re-configurability, non-volatility and open the path towards novel computational structures and approaches, for the traditional Von-Neumann architectures and beyond. These promising characteristics, coupled with the ever-increasing limitations faced by traditional CMOS-based storage and computational structures, have driven the research community towards completely revisiting the existing computing and storage paradigms, now focusing on providing hardware solutions for in-memory and neuromorphic computing. This has resulted in an intensified research activity in the device physics, striving to achieve circuit-worth devices, reliable compact models and novel architectures. The purpose of this paper is to provide a comprehensive overview of the device physics, issues related to its use in electronic circuits, methodologies for their compact modelling and simulations, and their integration in storage and computational structures.

CAPC: A Configurable Analog Pop-Count Circuit for Near-Memory Binary Neural Networks

Abstract: Currently, a major trend in artificial intelligence is to implement neural networks at the edge, within circuits with limited memory capacity. To reach this goal, the in-memory or near-memory implementation of low precision neural networks such as Binarized Neural Networks (BNNs) constitutes an appealing solution. However, the configurability of these approaches is a major challenge: in neural networks, the number of neurons per layer vary tremendously depending on the application, limiting the column-wise or row-wise mapping of neurons in memory arrays. To tackle this issue, we propose, for the first time, a Configurable Analog auto-compensate Pop-Count (CAPC) circuit compatible with column-wise neuron mapping. Our circuit has the advantage of featuring a very natural configurability through analog switch connections. We demonstrate that our solution saves 18% of area compared to non configurable conventional digital solution. Moreover, through extensive Monte-Carlo simulations, we show that the overall error probability remains low, and we highlight, at network level, the resilience of our configurable solution, with very limited accuracy degradation of 0.15% on the MNIST task, and 2.84% on the CIFAR-10 task.

Self-Rectifying Behavior and Analog Switching under Identical Pulses Using Tri-Layer RRAM Crossbar Array for Neuromorphic Systems

Abstract: This work analyzes the self-rectifying behavior and the response under identical pulses of tri-layer RRAMs in crossbar arrays to implement the synapse function. Our finding shows that tri-layer RRAMs allow to achieve a stable Low Resistance State (LRS) without complete oxide breakdown. The first RRAM layer works as tunneling barrier allowing to achieve on-state half-bias nonlinearity. Thanks to LRS nonlinearity the power consumption during synaptic programming is reduces of one order of magnitude. Analog switching under identical pulses allows to emulate synaptic plasticity. The multilevel states of conductance have been explained by the enlargement of the conductive filament (CF) in the broken oxide by means of physical based simulations.

Reliable ReRAM-based Logic Operations for Computing in Memory

Abstract: The development of non-conventional Von-Neumann architectures becomes essential for breakthrough computing in Internet of Things (IoT) devices. The main objective for IoT application is to lower as much as possible the power consumption to promote autonomy. The key to solve this challenge is to reduce the data transfer between memory and computing unit. As emerging non-volatile memories and especially resistive switching technologies (ReRAM) can today be co-integrated with CMOS on hybrid process, we propose in this paper to develop bitwise logic operations inside and close to the memory array. Using two transistors – one ReRAM (2T1R) memory cell architecture with differential approach to enhanced read reliability, we can perform logic operations without impacting the global memory architecture. Thanks to parallel data sensing, the structure enables fast computation of any bitwise logic operations (ID, AND, OR, XOR in their natural or complementary form) with high reliability, promoting the computing in memory (CiM) concept.

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.