56 research outputs found
Advances in Solid State Circuit Technologies
This book brings together contributions from experts in the fields to describe the current status of important topics in solid-state circuit technologies. It consists of 20 chapters which are grouped under the following categories: general information, circuits and devices, materials, and characterization techniques. These chapters have been written by renowned experts in the respective fields making this book valuable to the integrated circuits and materials science communities. It is intended for a diverse readership including electrical engineers and material scientists in the industry and academic institutions. Readers will be able to familiarize themselves with the latest technologies in the various fields
GRAPHENE-REINFORCED POLYMERIC NANOCOMPOSITES IN COMPUTER AND ELECTRONICS INDUSTRIES
Graphene is the newest member of the multidimensional graphite carbon family. Graphene is a two-dimensional atomic crystal formed by the arrangement of carbon atoms in the hexagonal network. It is the most rigid and thinnest material ever discovered and has a wide range of uses regarding its unique characteristics. It is expected that this material will create a revolution in the electronics industry. Graphene is a very powerful superconductor as the movability of charged particles is high on it, and additionally, because of the high surface energy and π electrons being free, graphene can be used in manufacturing many electronics devices. In this paper, the applications of graphene nanoparticles reinforced polymer nanocomposites in the computer and electronics industry are investigated. These nanoparticles have received much attention from researchers and craftsmen, because graphene has unique thermal, electrical and mechanical properties. Its use as a filler in very small quantities substantially enhances the properties of nanocomposites. There are various methods for producing graphene-reinforced polymer nanocomposites. These methods affect the amount of graphene dispersion within the polymer substrate and the final properties of the composite. The application and the properties of graphene-reinforced polymer nanocomposites are discussed along with examples of results published in the papers. To better understand such materials, the applications of these nanocomposites have been investigated in a variety of fields, including batteries, capacitors, sensors, solar cells, etc., and the barriers to the growth and development of these materials application as suggested by the researchers are discussed. As the use of these nanocomposites is developing and many researchers are interested in working on it, the need to study and deal with these substances is increasingly felt
Dispositifs de protection contre les décharges électrostatiques pour les applications radio fréquences et millimétriques
Ces travaux s'inscrivent dans un contexte où les contraintes vis-à-vis des décharges électrostatiques sont de plus en plus fortes, les circuits de protection sont un problème récurrent pour les circuits fonctionnant à hautes fréquences. La capacité parasite des composants de protection limite fortement la transmission du signal et peut perturber fortement le fonctionnement normal d'un circuit. Les travaux présentés dans ce mémoire font suite à une volonté de fournir aux concepteurs de circuits fonctionnant aux fréquences millimétriques un circuit de protection robuste présentant de faibles pertes en transmission, avec des dimensions très petites et fonctionnant sur une très large bande de fréquences, allant du courant continu à 100 GHz. Pour cela, une étude approfondie des lignes de transmission et des composants de protection a été réalisée à l'aide de simulations électromagnétiques et de circuits. Placés et fragmentées le long de ces lignes de transmission, les composants de protection ont été optimisés afin de perturber le moins possible la transmission du signal, tout en gardant une forte robustesse face aux décharges électrostatiques. Cette stratégie de protection a été réalisée et validée en technologies CMOS avancées par des mesures fréquentielles, électriques et de courant de fuite.Advanced CMOS technologies provide an easier way to realize radio-frequency integrated circuits (RFICs). However, the lithography dimension shrink make electrostatic discharges (ESD) issues become more significant. Specific ESD protection devices are embedded in RFICs to avoid any damage. Unfortunately, ESD protections parasitic capacitance limits the operating bandwidth of RFICs. ESD protection size dimensions are also an issue for the protection of RFICs, in order to avoid a significant increase in production costs. This work focuses on a broadband ESD solution (DC-100 GHz) able to be implemented in an I/O pad to protect RFICs in advanced CMOS technologies. Thanks to the signal transmission properties of coplanar / microstrip lines, a broadband ESD solution is achieved by implementing ESD components under a transmission line. The silicon proved structure is broadband; it can be used in any RF circuits and fulfill ESD target. The physical dimensions also enable easy on-chip integration.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF
Development of the readout electronics for the high luminosity upgrade of the CMS outer strip tracker
The High-luminosity upgrade of the LHC will deliver the dramatic increase in luminosity required for precision measurements and to probe Beyond the Standard Model theories.
At the same time, it will present unprecedented challenges in terms of pileup and radiation degradation.
The CMS experiment is set for an extensive upgrade campaign, which includes the replacement of the current Tracker with another all-silicon detector with improved performance and reduced mass.
One of the most ambitious aspects of the future Tracker will be the ability to identify high transverse momentum track candidates at every bunch crossing and with very low latency, in order to include tracking information at the L1 hardware trigger stage, a critical and effective step to achieve triggers with high purity and low threshold.
This thesis presents the development and the testing of the CMS Binary Chip 2 (CBC2), a prototype Application Specific Integrated Circuit (ASIC) for the binary front-end readout of silicon strip detectors modules in the Outer Tracker, which also integrates the logic necessary to identify high transverse momentum candidates by correlating hits from two silicon strip detectors, separated by a few millimetres.
The design exploits the relation between the transverse momentum and the curvature in the trajectory of charged particles subject to the large magnetic field of CMS.
The logic which follows the analogue amplification and binary conversion rejects clusters wider than a programmable maximum number of adjacent strips, compensates for the geometrical offset in the alignment of the module, and correlates the hits between the two sensor layers.
Data are stored in a memory buffer before being transferred to an additional buffer stage and being serially read-out upon receipt of a Level 1 trigger.
The CBC2 has been subject to extensive testing since its production in January 2013: this work reports the results of electrical characterization, of the total ionizing dose irradiation tests, and the performance of a prototype module instrumented with CBC2 in realistic conditions in a beam test.
The latter is the first experimental demonstration of the Pt-selection principle central to the future of CMS.
Several total-ionizing-dose tests highlighted no functional issue, but observed significant excess static current for doses <1 Mrad.
The source of the excess was traced to static leakage current in the memory pipeline, and is believed to be a consequence of the high instantaneous dose delivered by the x-ray setup.
Nevertheless, a new SRAM layout aimed at removing the leakage path was proposed for the CBC3. The results of single event upset testing of the chip are also reported, two of the
three distinct memory circuits used in the chip were proven to meet the expected
robustness, while the third will be replaced in the next iteration of the chip.
Finally, the next version of the ASIC is presented, highlighting the additional features of the final prototype, such as half-strip resolution, additional trigger logic functionality, longer trigger latency and higher rate, and fully synchronous stub readout.Open Acces
Energy autonomous systems : future trends in devices, technology, and systems
The rapid evolution of electronic devices since the beginning of the nanoelectronics era has brought about exceptional computational power in an ever shrinking system footprint. This has enabled among others the wealth of nomadic battery powered wireless systems (smart phones, mp3 players, GPS, …) that society currently enjoys. Emerging integration technologies enabling even smaller volumes and the associated increased functional density may bring about a new revolution in systems targeting wearable healthcare, wellness, lifestyle and industrial monitoring applications
Gate oxide failure in MOS devices
The thesis presents an experimental and theoretical investigation of gate oxide
breakdown in MOS networks, with a particular emphasis on constant voltage overstress
failure. It begins with a literature search on gate oxide failure mechanisms, particularly
time-dependent dielectric breakdown, in MOS devices.
The experimental procedure is then reported for the study of gate oxide
breakdown under constant voltage stress. The experiments were carried out on
MOSFETs and MOS capacitor structures, recording the characteristics of the devices
before and after the stress. The effects of gate oxide breakdown in one of the transistors
in an nMOS inverter were investigated and several parameters were found to have
changed.
A mathematical model for oxide breakdown, based on physical mechanisms, is
proposed. Both electron and hole trapping occurred during the constant voltage stress.
Breakdown appears to take place when the trapped hole density reach a critical value.
PSPICE simulations were performed for the MOSFETs, nMOS inverter and
CMOS logic circuits. Two models of MOSFET with gate oxide short were validated.
A good agreement between experiments and simulations was achieved
Potential and Challenges of Analog Reconfigurable Computation in Modern and Future CMOS
In this work, the feasibility of the floating-gate technology in analog computing platforms in a scaled down general-purpose CMOS technology is considered. When the technology is scaled down the performance of analog circuits tends to get worse because the process parameters are optimized for digital transistors and the scaling involves the reduction of supply voltages. Generally, the challenge in analog circuit design is that all salient design metrics such as power, area, bandwidth and accuracy are interrelated. Furthermore, poor flexibility, i.e. lack of reconfigurability, the reuse of IP etc., can be considered the most severe weakness of analog hardware. On this account, digital calibration schemes are often required for improved performance or yield enhancement, whereas high flexibility/reconfigurability can not be easily achieved. Here, it is discussed whether it is possible to work around these obstacles by using floating-gate transistors (FGTs), and analyze problems associated with the practical implementation. FGT technology is attractive because it is electrically programmable and also features a charge-based built-in non-volatile memory. Apart from being ideal for canceling the circuit non-idealities due to process variations, the FGTs can also be used as computational or adaptive elements in analog circuits.
The nominal gate oxide thickness in the deep sub-micron (DSM) processes is too thin to support robust charge retention and consequently the FGT becomes leaky. In principle, non-leaky FGTs can be implemented in a scaled down process without any special masks by using “double”-oxide transistors intended for providing devices that operate with higher supply voltages than general purpose devices. However, in practice the technology scaling poses several challenges which are addressed in this thesis.
To provide a sufficiently wide-ranging survey, six prototype chips with varying complexity were implemented in four different DSM process nodes and investigated from this perspective. The focus is on non-leaky FGTs, but the presented autozeroing floating-gate amplifier (AFGA) demonstrates that leaky FGTs may also find a use. The simplest test structures contain only a few transistors, whereas the most complex experimental chip is an implementation of a spiking neural network (SNN) which comprises thousands of active and passive devices. More precisely, it is a fully connected (256 FGT synapses) two-layer spiking neural network (SNN), where the adaptive properties of FGT are taken advantage of. A compact realization of Spike Timing Dependent Plasticity (STDP) within the SNN is one of the key contributions of this thesis.
Finally, the considerations in this thesis extend beyond CMOS to emerging nanodevices. To this end, one promising emerging nanoscale circuit element - memristor - is reviewed and its applicability for analog processing is considered. Furthermore, it is discussed how the FGT technology can be used to prototype computation paradigms compatible with these emerging two-terminal nanoscale devices in a mature and widely available CMOS technology.Siirretty Doriast
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Design of custom CMOS amplifiers for nanoscale bio-interfaces
The miniaturization of electronics is a technique that holds a lot of potential in improving system performance in a variety of applications. The simultaneous miniaturization of sensors into the nano-scale has provided new ways to probe biological systems. Careful co-design of these electronics and sensors can unlock measurements and experiments that would otherwise be impossible to achieve. This thesis describes the design of two such instrumentation amplifiers and shows that significant gains in temporal resolution and noise performance are possible through careful optimization.
A custom integrated amplifier is developed for improving the temporal resolution in nanopore recordings. The amplifier is designed in a commercial 0.18 μm complementary metal-oxide-semiconductor (CMOS) process. A platform is then built with the amplifier at its core that integrates glass-passivated solid-state nanopores to achieve measurement bandwidth over an order of magnitude greater than the state of the art. The use of wavelet transforms for denoising the data and further improving the signal-to-noise ratio (SNR) is then explored.
A second amplifier is designed in a 0.18 μm CMOS process for intracellular recordings from neurons. The amplifier contains all the compensation circuitry required for canceling the effects of the electrode non-idealities. Compared to equivalent commercial systems and the state of the art, the amplifier performs comparably or better while consuming orders of magnitude lower power.
These systems can inform the design of extremely miniaturized application-specific integrated amplifiers of the future
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