Defect localization using voltage contrast IDDQ testing

I_DDQ testing detects a majority of faults occurring in logic,ICs. Nethertheless, it has not eliminated the complex task of fault isolation at the silicon level of ICs.Liquid Crystak or Emission Microscopy can deal with this challenge. Unfortunately these two techniques lack sensitivity for some defects when the abnormal current consumption (I_DDQ) remains weak.On the other hand we can use very powerful tools like the electron beam tester to deeply analyze faulty devices by internal contactless testing. In some laboratories, people have underlined the interest of merging the two techniques (I_DDQ testing and Voltage Contrast) to get fast and accurate defect localization. In this paper, we will move on to the next step of identifying practical key issues necessary for obtaining results on current VLSI.     

Enhanced optical trapping and arrangement of nano-objects in a plasmonic nanocavity

Gentle manipulation of micrometer-sized dielectric objects with optical forces has found many applications in both life and physical sciences. To further extend optical trapping toward the true nanometer scale, we present an original approach combining self-induced back action (SIBA) trapping with the latest advances in nanoscale plasmon engineering. The designed resonant trap, formed by a rectangular plasmonic nanopore, is successfully tested on 22 nm polystyrene beads, showing both single- and double-bead trapping events. The mechanism responsible for the higher stability of the double-bead trapping is discussed, in light of the statistical analysis of the experimental data and numerical calculations. Furthermore, we propose a figure of merit that we use to quantify the achieved trapping efficiency and compare it to prior optical nanotweezers. Our approach may open new routes toward ultra-accurate immobilization and arrangement of nanoscale objects, such as biomolecules.     

Transmission Electron Microscopy and UV–vis–IR Spectroscopy Analysis of the Diameter Sorting of Carbon Nanotubes by Gradient Density Ultracentrifugation

Diameter separation of single‐walled carbon nanotubes is achieved via the density gradient ultracentrifugation process. Statistical analysis of the separated samples is performed using high‐resolution transmission electron microscopy (HRTEM). The evolution of the diameter distribution with respect to the gradient density is extracted by analyzing hundreds of HRTEM images, and the results are found to be consistent with those estimated by UV–vis–IR spectroscopy. The efficiency of the separation process can be quantitatively characterized by the standard deviation of the diameter distribution, which is determined from the TEM analyses. This particular study indicated that for electric arc nanotubes dispersed in sodium cholate, diameter sorting is more efficient in the upper part of the gradient.     

New experimental approach for failure prediction in electronics: Topography and deformation measurement complemented with acoustic microscopy

Topography and Deformation Measurements (T.D.M.) under thermo-mechanical solicitation is a new approach for localising and quantifying deformation of electronic assemblies. Cooling and heating capabilities, with different temperature rate and maximum, following JEDEC thermal profiles for example, have been applied on different components before and after assembly using real time Topography and Deformation Measurements.The interest in being able to perform z and (x, y) deformation measurements for traction /compression and shear stress evaluation will be shown. Using acoustic microscopy before and after thermal stress gives the possibility to detect both the conditions in which elastic limits may have exceeded at interfaces, which interface is concerned and the speed at which delamination occurs.Complementarities of this new technique with acoustic microscopy and simulation will be shown for failure prediction applications.     

Verification of Full-Scale Ozone Contactor Inactivation Performance Using Biodosimetry

A biodosimetric technique was used to verify the concentration-contact time (CT) values [CT10, CT integrated disinfection design framework (CT-IDDF), CT segregated flow analysis (CT-SFA)] of the ozone contactors of the DesBaillets water treatment plant (Montreal), using indigenous aerobic spore formers (ASFs) as indicators of disinfection efficiency. ASF measurement in ozonated water was performed using a large water sample concentration method. Four assays, completed over a 6-week period, involved the implementation of biodosimetric calibration curves using an ozone pilot apparatus and followed by full-scale verifications. ASF inactivation kinetics were well described by a simple Chick–Watson model. The most accurate data also indicated that the CT10 underestimates the effective CT (by 1.2–1.9-fold), whereas the CT-IDDF and CT-SFA overestimate it (by 1.0–1.7-fold and 0.9–1.5-fold, respectively). Underestimation from CT10 was more pronounced with increased ozone dose while overestimation from CT-IDDF and CT-SFA is most likely due to the difficulty in obtaining a representative ozone residual profile within the contactor. The use of segregated flow analysis provided the best estimate of disinfection performance. Biodosimetry is useful in measuring the effective CT transferred, in verifying model predictions, and in determining the influence of water quality on microbial inactivation.     

Single-graded CIGS with narrow bandgap for tandem solar cells

Multi-junction solar cells show the highest photovoltaic energy conversion efficiencies, but the current technologies based on wafers and epitaxial growth of multiple layers are very costly. Therefore, there is a high interest in realizing multi-junction tandem devices based on cost-effective thin film technologies. While the efficiency of such devices has been limited so far because of the rather low efficiency of semitransparent wide bandgap top cells, the recent rise of wide bandgap perovskite solar cells has inspired the development of new thin film tandem solar devices. In order to realize monolithic, and therefore current-matched thin film tandem solar cells, a bottom cell with narrow bandgap (~1 eV) and high efficiency is necessary. In this work, we present Cu(In,Ga)Se₂ with a bandgap of 1.00 eV and a maximum power conversion efficiency of 16.1%. This is achieved by implementing a gallium grading towards the back contact into a CuInSe₂ base material. We show that this modification significantly improves the open circuit voltage but does not reduce the spectral response range of these devices. Therefore, efficient cells with narrow bandgap absorbers are obtained, yielding the high current density necessary for thin film multi-junction solar cells.     

A security approach for off-chip memory in embedded microprocessor systems

This paper describes a complete off-chip memory security solution for embedded systems. Our security core is based on a one-time pad (OTP) encryption circuit and a CRC-based integrity checking module. These modules safeguard external memory used by embedded processors against a series of well-known attacks, including replay attacks, spoofing attacks and relocation attacks. Our implementation limits on-chip memory space overhead to less than 33% versus memory used by a standard microprocessor and reduces memory latency achieved by previous approaches by at least half. The performance loss for software execution with our solution is only 10% compared with a non-protected implementation. An FPGA prototype of our security core has been completed to validate our findings.     

Reasoning over time into models with DataTime

Software and Systems Modeling - Models at runtime have been initially investigated for adaptive systems. Models are used as a reflective layer of the current state of the system to support the...     

On the Lyapunov-based adaptive control redesign for a class of nonlinear sampled-data systems

Stabilization of the exact discrete-time models of a class of nonlinear sampled-data systems, with an unknown parameter, is addressed. Given a Lyapunov-based continuous-time adaptive controller that ensures some stability properties for the closed-loop system, a sufficient condition for the design of high order discrete-time controllers is given. The stability analysis is carried out considering the truncated Fliess series of the Lyapunov difference equation. Due to the appearance of power terms of the unknown parameter, the problem is reparameterized in a convex-like form and an estimation law for the new unknown parameter is derived with no need of overparametrization or projection techniques. Then, assuming appropriate conditions hold, high order controllers can be designed. The boundedness of the extended state vector is ensured under some conditions, for a sufficiently small sampling period. It is shown how increasing the controller order can improve system performance.