Analysis of Dynamic Faults in Embedded-SRAMs: Implications for Memory Test

This paper presents the results of resistive-open defect insertion in different locations of Infineon 0.13 m embedded-SRAM with the main purpose of verifying the presence of dynamic faults. This study is based on the injection of resistive defects as their presence in VDSM technologies is more and more frequent. Electrical simulations have been performed to evaluate the effects of those defects in terms of detected functional faults. Read destructive, deceptive read destructive and dynamic read destructive faults have been reproduced and accurately characterized. The dependence of the fault detection has been put in relation with memory operating conditions, resistance value and clock cycle, and the importance of at speed testing for dynamic fault models has been pointed out. Finally resistive Address Decoder Open Faults (ADOF) have been simulated and the conditions that maximize the fault detection have been discussed as well as the resulting implications for memory test.This work has been partially funded by the French government under the framework of the MEDEA + A503 ASSOCIATE European program.A paper based on this work was presented at the Eighth IEEE European Test Workshop, Maastricht, The Netherlands, May 2003.Simone Borri received the M.Sc. Degree (summa cum laude) in Electronics Engineering from the University of Pisa (Italy) in 1995. In 1997 he joined STMicroelectronics as a digital designer in the DSP development group of S.S.D. (formerly Parthus, now Ceva), Dublin, Ireland. From 1998 to 2000 he was with ST Microelectronics, Milan, Italy as ASIC DSP designer in the Car Communication business unit. Since 2000 he is with Infineon Technologies, Sophia-Antipolis, France as Staff design engineer in the embedded-SRAM design group. He has recently joined the Secure Mobile System Business Unit. His current interests include BIST, DFT techniques and SoC verification. Simone is an IEEE member since 1995.Magali Hage-Hassan was born near Lyon (France) in 1979. She received a Master of Science degree of Microelectronics and Automatics from the Institute of Engineering Sciences of Montpellier in 2003. She is currently working for Infineon in the memory library department in Sophia-Antipolis. She participated to the European research project MEDEA associate. Hage-Hassans interest include memory test.Luigi Dilillo was born in Barletta (Italy) in 1974. At this moment he is doing his last year of Ph.D. in the Microelectronics Department of the Laboratory of Informatics, Robotics and Microelectronics of Montpellier (LIRMM) in France. He received his degree in Electrical Engineering in 2001, at Politecnico di Torino (Italy). His researches include MEMS and digital circuits. At this moment he is working on delay-fault testing, and memory testing.Patrick Girard is presently Researcher at CNRS (French National Center for Scientific Research), and works in the Microelectronics Department of the LIRMM (Laboratory of Informatics, Robotics and Microelectronics of Montpellier—France). His research interests include the various aspects of digital testing, with special emphasis on DfT, logic BIST, delay fault testing and diagnosis, low power testing and memory testing. He has authored and co-authored 1 book and more than 100 papers on these fields. He has managed several European research projects and industrial research contracts. He is Editor-in-Chief of JOLPE—Journal of Low Power Electronics, and Associate Editor of JEC—Journal of Embedded Computing. He will serve as Program vice-Chair for the International Conference on Embedded And Ubiquitous Computing in 2005 and as Program Chair for the IEEE International Workshop on Electronic Design, Test & Applications in 2006. He is also topic chair of two European conferences (DATE and ETS) and is member of the program committee of several other international conferences. Patrick GIRARD obtained the Ph.D. degree in microelectronics from the University of Montpellier in 1992 and the Habilitation à Diriger des Recherches degree from the University of Montpellier in 2003.Serge Pravossoudovitch was born in 1957. He is currently professor in the electrical and computer engineering department of the University of Montpellier and his research activities are performed at LIRMM (Laboratoire dInformatique, de Robotique et de Microélectronique de Montpellier). He got the Ph.D. degree in electrical engineering in 1983 for his work on symbolic layout for IC design. Since 1984, he is working in the testing domain. He obtained the doctorat détat degree in 1987 for his work on switch level automatic test pattern generation. He is presently interested in memory testing, delay fault testing, design for testability and power consumption optimization. He has authored and co-authored numerous papers on these fields, and has supervised several Ph.D. dissertations. He has also participated to several European projects (Microelectronic regulation, Esprit, Medea).Arnaud Virazel was born in Montpellier (France) in 1974. He is presently assistant professor at the university of Montpellier, and works with the LIRMM (Laboratoire dInformatique, de Robotique et de Microélectronique de Montpellier). He received the B.Sc. (1995) and the M.Sc. (1997) degrees in Electrical Engineering and the Ph.D. (2001) degree in Microelectronics, all from the University of Montpellier/LIRMM. A. Virazels interests include delay testing, memory testing and power optimization during test.     

Encoder-free odometric system for autonomous microrobots

This paper describes an odometric system for autonomous microrobots based on the optical properties of a motor–wheel transmission for motion feedback. We demonstrate that infra-red light, reflected from this mechanical system, shows distinctive periodic changes of amplitude, correlated with the motion of the robot. Real-time odometric signal processing, performed on a small embedded microcontroller, allows accurate movement detection for each wheel and is used for motion control, self-calibration, and calculation of differential and absolute velocity, displacement and rotation. We demonstrate some applications of this on-board odometric system in swarm robot experiments. This approach can also be applied to other industrial or academic mechatronic systems, where size or computational power are limiting factors.     

Engineering of Complex Macroporous Materials Through Controlled Electrodeposition in Colloidal Superstructures

Macroporous materials with a sophisticated architecture are obtained by electrochemical deposition of gold or polypyrrole in colloidal‐crystal templates. The Langmuir–Blodgett technique enables assembly of sub‐micrometric silica‐particle monolayers on conductive gold substrates, thus leading to colloidal superstructures with an unprecedented control of their features at the single‐bead‐layer level. This allows the integration of deliberate planar defects or the elaboration of well‐defined gradients in terms of sphere size. Controlled infiltration using electrochemical deposition preserves the architecture of the original templates and leads to inverse opals with well‐defined pore structures after the removal of the inorganic particles.     

Low Power Digital Frequency Conversion Architectures

State-of-the-art data communication systems make extensive use of digital hardware. Besides baseband modulation functions, also the frequency tuning functions are now being shifted from analog to digital implementation. Integration, cost and ease of programming are the primary motivations for doing this. This paper presents an alternative to the traditional digital frequency conversion architectures. The proposed architecture achieves low power as well as high speed operation, and achieves this dual goal by reducing programmability. A multi-rate filtering approach is used, which is applicable for both upconversion and downconversion of quadrature modulated data.     

L’arithmétique sur une surface percée

This article gives the principles for diophantine approximation of real numbers by rationals. The measure of the approximation is given, with the general context for Markoff theory. The hyperbolic structure modelling the geometry of quadratic forms associated is presented. The Markoff theory is then interpreted as giving the geodesics bordering the hole of a punctured torus. The geometric interpretation of the class number of quadratic forms on a punctured sphere is also given. More generally, the link is made with Riemann surfaces and the theories of Teichmuller and Thurston for closed surfaces of negative Euler Poincaré characteristic.     

Vlsi solutions for voice and channel coders

In the last few years we have seen a relevant transformation of the telephone network, with an extensive digitalization of the voice transmission and switching able now to reach the subscriber. In the meanwhile various techniques have been implemented to exploit data transmission in an environment designed for voice only. This paper will review this important transformation and its future perspective from the point of view of theic industry by considering several analog/digital basic realization inpcm, analog modem,isdn and radio-communication fields.     

Fluorescence diagnostics of oil pollution in coastal marine waters by use of artificial neural networks

We discuss the problems with and the real possibilities of determining oil pollution in situ in coastal marine waters with fluorescence spectroscopy and of using artificial neural networks for data interpretation. In general, the fluorescence bands of oil and aquatic humic substance overlap. At oil concentrations in water from a few to tens of micrograms per liter, the intensity of oil fluorescence is considerably lower than that of humic substances at concentrations that typically are present in coastal waters. Therefore it is necessary to solve the problem of separating the small amount of oil fluorescence from the humic substance background in the spectrum. The problem is complicated because of possible interactions between the components and variations in the parameters of the fluorescence bands of humic substances and oil in water. Fluorescence spectra of seawater samples taken from coastal areas of the Black Sea, samples prepared in the laboratory, and numerically simulated spectra were processed with an artificial neural network. The results demonstrate the possibility of estimating oil concentrations with an accuracy of a few micrograms per liter in coastal waters also in cases in which the contribution from other organic compounds, primarily humic substances, to the fluorescence spectrum exceeds that of oil by 2 orders of magnitude and more.     

X‐Ray Absorption Spectroscopy Characterizations on PGM‐Free Electrocatalysts: Justification,Advantages, and Limitations

Transition metals embedded in nitrogen‐doped carbon matrices (denoted as M‐N‐C) are the leading platinum group metal (PGM)‐free electrocatalysts for the oxygen reduction reaction (ORR) in acid, and are the most promising candidates for replacing platinum in practical devices such as fuel cells. Two of the long‐standing puzzles in the field are the nature of active sites for the ORR and the reaction mechanism. Poor understanding of the structural and mechanistic basis for the exceptional ORR activity of M‐N‐C electrocatalysts impedes rational design for further improvements. Recently, synchrotron‐based X‐ray absorption spectroscopy (XAS) has been successfully implemented to shed some light on these two issues. In this context, a critical review is given to detail the contribution of XAS to the advancement of the M‐N‐C electrocatalysis to highlight its advantages and limitations.     

Practical methods for a posteriori error estimation in engineering applications

This work presents an extension of the goal‐oriented error estimation technique to the engineering analysis of three‐dimensional linear elastic bodies. In the series of examples shown, the errors are estimated with respect to local displacement and stress components. The paper also introduces novel means to compute lower bounds on the error in the energy norm based on a cost‐effective postprocessing of the upper bound error estimates. The numerical results indicate that the method can be used effectively for complex engineering applications. Copyright © 2003 John Wiley & Sons, Ltd.