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.

An Approach to Minimize the Test Configuration for the Logic Cells of the Xilinx XC4000 FPGAs Family

Abstract: This paper describes an approach to minimize the number of test configurations for testing the logic cells of a RAM-based FPGA taking into account the configurability of such flexible device. The proposed approach concerns the XILINX 4000 family. On this example of FPGA, a bottom-up test technique is first used to generate test configurations for the elementary modules, then test configurations for a single logic cell, and finally test configurations for the m × m array of logic cells. In this bottom-up technique, it is shown that the key point is the minimization of the number of test configurations for a logic cell. An approach for the logic cell of the XILINX4000 family is then described to define a minimum number of test configurations knowing the test configurations of its logic modules. This approach gives only 5 test configurations for the XILINX4000 family while the previous published works concerning Boolean testing of this FPGA family gives 8 or 21 test configurations.

Ultra Low Power Charge Pump with Multi-Step Charging and Charge Sharing

Abstract: a new approach for improving the power efficiency of the conventional four-phase charge pump is presented. Based on the multi-step capacitor charging and the charge sharing concept, the charge pump design is able to reduce the overall power consumption by 35% compared to the conventional four-phase charge pump and by 15% compared to a charge sharing charge pump, for an output current of 200μA with 12V output voltage.

Test Structure for Process and Product Evaluation

Abstract: The objective of this paper is to present a test structure introduced in the scribe lines designed to detect process drift and to characterize product performances, i.e. delay and VDDmin. A brief overview of the structure, designed in a ST-Microelectronics 130nm technology, is given. The main advantages of the structure are to be introduced in the scribe line and to have a complex architecture close to the product back-end configurations. A specific test flow is applied to the structure in order to extract relevant data (frequency, delay and bias). The monitoring efficiency of the structure is validated with measurement correlation performed on the structure data, parametric test data and full test chip data.

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.