Standard Gate Research Articles

Design Of Hardware Efficient High Speed Multiplier Using Modified Ternary Logic

This paper presents a novel design for a parallel multiplier using ternary logic based on reduced routing and chip area, an alternative to conventional binary logic. The methodology of ternary logic is used for the design of standard inverter(STI), negative inverter (NTI), positive inverter(PTI), NAND and NOR gates. The basic gates are then used for design of multiplier with partial product reduction elements in the same logic. As a further optimization, we have implemented the multiplier with a combination of binary and ternary logic to enjoy the benefits of two. The proposed and optimized designs are designed using VHDL and synthesized using SYNOPSIS software. Extensive simulation results show that the proposed modified ternary logic designs consume significantly lower power and delay compared to ternary designs.

Photoconductivity, photoluminescence and optical Kerr nonlinear effects in zinc oxide films containing chromium nanoclusters

Chromium doped zinc oxide thin solid films were deposited on soda–lime glass substrates. The photoconductivity of the material and its influence on the optical behavior was evaluated. A non-alkoxide sol–gel synthesis approach was used for the preparation of the samples. An enhancement of the photoluminescence response exhibited by the resulting photoconductive films with embedded chromium nanoclusters is presented. The modification in the photoconduction induced by a 445 nm wavelength was measured and then associated with the participation of the optical absorptive response. In order to investigate the third order optical nonlinearities of the samples, a standard time-resolved Optical Kerr Gate configuration with 80 fs pulses at 830 nm was used and a quasi-instantaneous pure electronic nonlinearity without the contribution of nonlinear optical absorption was observed. We estimate that from the inclusion of Cr nanoclusters into the sample results a strong optical Kerr effect originated by quantum confinement. The large photoluminescence response and the important refractive nonlinearity of the photoconductive samples seem to promise potential applications for the development of multifunctional all-optical nanodevices.

Fully Automated, Testable Design of Fine-Grained Triple Mode Redundant Logic

A fully automated logic design methodology for radiation hardened by design high-speed logic using fine-grained triple modular redundancy (TMR) is presented. The methodology and circuits leverage commercial logic design automation tools. The circuit approach is validated for hardness using both heavy ion and proton broad beam testing. The base TMR self-correcting master-slave flip-flop is described, including testability features that disable the self-correction. The flow allows hardening of any synthesizable logic at clock frequencies comparable to unhardened designs and supports standard low-power techniques, e.g., clock gating and supply voltage scaling.

Relating hysteresis and electrochemistry in graphene field effect transistors

Hysteresis and commonly observed p-doping of graphene based field effect transistors (FETs) have been discussed in reports over the last few years. However, the interpretation of experimental works differs; and the mechanism behind the appearance of the hysteresis and the role of charge transfer between graphene and its environment is not clarified yet. We analyze the relation between electrochemical and electronic properties of graphene FETs in a moist environment extracted from the standard back gate dependence of the graphene resistance. We argue that graphene based FETs on a regular SiO2 substrate exhibit behavior that corresponds to electrochemically induced hysteresis in ambient conditions, and can be caused by a charge trapping mechanism associated with sensitivity of graphene to the local pH.

A Franco-Belgian Workshop on PNH Diagnosis by Flow Cytometry: Results of a Multicentric Evaluation of Technical Aspects and Standardized Procedures of Reference Assays on Behalf of the French Association of Cytometry (AFC)

Abstract 4370In 2010, technical guidelines have been published in order to standardize the diagnosis of Paroxysmal Nocturnal Hemoglobinuria (PNH) by multiparameter flow cytometry. General recommendations have been released including the use of a new reagent, the FLAER and different monoclonal antibodies (MoAb).To make an inventory of the practices and to evaluate the contribution of these new guidelines in routine diagnosis, we have conducted a multicentric study in 39 French and Belgian laboratories comparing three different strategies. EDTA blood samples from 141 healthy controls, 80 myelodysplasia (MDS), 83 myelocytosis and 76 previously diagnosed PNH were analysed. We have strived to address the question of sensitivity and defined a preanalytic approach, using red blood cell lysis prior to staining, to allow the recording of a high number of polymorphonuclear leucocytes (PMN >200 000). We applied two published techniques (i) Nakao's strategy, a two-color staining (CD55/CD59 versus CD11b) (ii) the North American guidelines through a multicolor panel (five or six colors including FLAER and MoAb) and (iii) a strategy including MoAb (workshop combination) without FLAER. Reagents were provided by the companies. Analysis were performed on 3 different flow cytometers from Beckman Coulter (FC500: n=17, Navios, n=9) and Becton Dickinson (Canto II: n=13).Whatever the strategy used and irrespective of the flow cytometer, our results showed that each center was able to reach a sensitivity of 1%. When considering PMN, a 0.1% threshold was even achievable in most cases after the first round of interpretation. The results on monocyte population were poorer due to the low number of cell recorded. As our aim was to improve the ability to detect PNH clones and harmonize the multiparametric techniques, we established a standardized gating procedure using either basophils, lymphocytes or NK cells as internal control cell populations. Then a second round of data interpretation was performed. When considering the healthy control samples, the comparison of the two sets of results showed that there was a striking improvement of the cellular background after applying the standardized gating procedure on PMN population. A 1 to 2-log decrease was observed with the 6-color combinations. Therefore we refined the performance of the technique by establishing the limit of detection (LOD), defined as the mean cellular background + 2 standard deviations, for each technique and staining combinations. Using the standardized procedure, we found that LOD determined on healthy controls samples with more than 105 PMN were: 0.0054%, 0.0024% on the 6 color cytometers Navios and Canto, 0.092% on the 5 color cytometer FC500 with combination (ii) and 0.0072%, 0.0044% and 0.206% respectively with combination (iii). As myelocytosis and MDS have a higher cellular background after the first round of interpretation, the improvement is more significant when samples were tested using the optimized procedure. Thus, we observed that, compared to healthy controls, the LOD determined on myelocytosis and MDS samples was not modified in the series processed on Canto ((ii) 0.0048% and 0.0019%, respectively, (iii) 0.0066% and 0.0031%) whereas it was mildly increased in Navios series ((ii) 0.0594% and 0.0106%, (iii) 0.0148% and0.0246%) and in FC500 series ((ii) 0.1837% and 0.7120%, (iii) 0.7557% and 0.5862%). Finally, the procedure was successfully validated on PNH samples since we observed no obvious modifications of the proportion of the clone after applying the gating.In conclusion, this study shows that the detection of large clones can be achieved with all approaches, the detection of small clones requiring standardized preanalytic, analytic and interpretation procedures. This study highlights the contribution of the use of control cell populations in the gating strategy and supports the use of FLAER. Moreover, an optimized procedure appears to reach a very good LOD of 10−4. Finally, there is a need for the implementation of quality controls including pathological samples to ensure technical validation and QC monitoring. Disclosures:Le Garff-Tavernier:Alexion: Honoraria. Letestu:Alexion: Honoraria, Research Funding. Drenou:Alexion: Honoraria.

Detection and monitoring of normal and leukemic cell populations with hierarchical clustering of flow cytometry data

Flow cytometry is a valuable tool in research and diagnostics including minimal residual disease (MRD) monitoring of hematologic malignancies. However, its gradual advancement toward increasing numbers of fluorescent parameters leads to information rich datasets, which are challenging to analyze by standard gating and do not reflect the multidimensionality of the data. We have developed a novel method to analyze complex flow cytometry data, based on hierarchical clustering analysis (HCA) but with a new underlying algorithm, using Mahalanobis distance measure. HCA is scalable to analyze complex multiparameter datasets (here demonstrated on up to 12 color flow cytometry and on a 20-parameter synthetic dataset). We have validated this method by comparison with standard gating approaches when performed independently by expert cytometrists. Acute lymphoblastic leukemia blast populations were analyzed in diagnostic and follow-up datasets (n = 123) from three centers. HCA results correlated very well (Passing-Bablok correlation coefficient = 0.992, slope = 1, intercept = -0.01) with standard gating data obtained by the I-BFM FLOW-MRD study group. To further improve the performance in follow-up samples with low MRD levels and to automate MRD detection, we combined HCA with support vector machine (SVM) learning. HCA in combination with SVM provides a novel diagnostic tool that not only allows analysis of increasingly complex flow cytometry data but also is less observer-dependent compared with classical gating and has potential for automation.

Basophils and plasmacytoid dendritic cells are potential sources for error in flow cytometric monitoring of patients receiving anti-CD22 therapies. AKA not all anti-CD22 antibodies are created equal

Basophils and plasmacytoid dendritic cells are potential sources for error in flow cytometric monitoring of patients receiving anti-CD22 therapies. AKA not all anti-CD22 antibodies are created equal

Novel Timing Yield Improvement Circuits for High-Performance Low-Power Wide Fan-In Dynamic OR Gates

Dynamic gates are preferred in the design of high-performance modules in modern microprocessors due to the relatively high speed of dynamic gates compared with that of standard CMOS gates. These high performance modules have strict timing constraints. Due to the increased process variations in scaled technologies, the dynamic circuit delay exhibits a substantial variability around its nominal value. This delay variability results in violating the timing constraints, and correspondingly, causes a timing yield loss. In this paper, novel negative capacitance circuits are developed, for the first time, to statistically improve the timing yield under process variations. Post layout simulation results, referring to an industrial hardware-calibrated TSMC 65 nm CMOS technology, show that the adoption of the negative capacitance circuit to a 64-input wide dynamic OR gate is capable of improving the timing yield from 50% to 100%. Moreover, the negative capacitance circuit adoption results in reducing the delay variability at the expense of excess power overhead.

Broadband spectroscopy of dynamic impedances with short chirp pulses

An impedance spectrum of dynamic systems is time dependent. Fast impedance changes take place, for example, in high throughput microfluidic devices and in operating cardiovascular systems. Measurements must be as short as possible to avoid significant impedance changes during the spectrum analysis, and as long as possible for enlarging the excitation energy and obtaining a better signal-to-noise ratio (SNR). The authors propose to use specific short chirp pulses for excitation. Thanks to the specific properties of the chirp function, it is possible to meet the needs for a spectrum bandwidth, measurement time and SNR so that the most accurate impedance spectrogram can be obtained. The chirp wave excitation can include thousands of cycles when the impedance changes slowly, but in the case of very high speed changes it can be shorter than a single cycle, preserving the same excitation bandwidth. For example, a 100 kHz bandwidth can be covered by the chirp pulse with durations from 10 µs to 1 s; only its excitation energy differs also 105 times. After discussing theoretical short chirp properties in detail, the authors show how to generate short chirps in the microsecond range with a bandwidth up to a few MHz by using digital synthesis architectures developed inside a low-cost standard field programmable gate array.

SAT based timing analysis for fixed and rise/fall gate delay models

This paper proposes a SAT based technique for timing analysis by an accurate modeling of event propagation within gate-level circuits. The accuracy of the result depends on the level of detail with which circuit activity is modeled. However, the combinatorial blowup in the size and complexity of the problem is the main bottleneck in any detailed modeling. The proposed technique overcomes this problem by an efficient SAT modeling of events at the nodes of the circuit which scales very smoothly with increase in size of the circuit without sacrificing on accuracy even with industry standard gate delays of 0.01ns granularity. This improvement in performance enables the modeling of more complex gate delay models like the rise/fall delay model which can simulate circuit activity more realistically than the fixed gate delay model.

Study of Switching Characteristics of Static Induction Thyristor for Pulsed Power Applications

It is difficult to design a standard gate driver for optimal switching control of a static induction thyristor (SI-Thy) because of its unique internal structure and the direct commutation switching characteristic between the gate and cathode terminals during the transient turn-on and turn-off switching phases. Therefore, it is important to develop a simple and effective gate driver for achieving optimal fast turn-on and stable switching operations in an SI-Thy under hard-switching conditions. To achieve faster turn-on switching time with shorter gate delay time, impedance matching between the SI-Thy and the turn-on driving circuit component in the gate driver can be realized with additional circuit modification through this paper. To ensure higher stabilities in the turn-off switching phase, forced commutation techniques and additional auxiliary circuits in the gate driver have been devised to suppress the latchup and to eliminate potential ringing possibility. We have demonstrated that our designed and tested gate driver for realizing optimal switching characteristics of an SI-Thy is effective, particularly in the gate driving circuits for various pulsed-power switching applications.

Design and Optimization of Power-Gated Circuits With Autonomous Data Retention

Power gating has been widely employed to reduce subthreshold leakage. Data retention elements (flip-flops and isolation circuits) are used to preserve circuit states during standby mode, if the states are needed again after wake-up. These elements must be controlled by an external power management unit, causing a network of control signals implemented with extra wires and buffers. A power-gated circuit with autonomous data retention (APG) is proposed to remove the overhead involved in control signals. Retention elements in APG derive their control by detecting rising potential of virtual ground rails when power gating starts, i.e., they control themselves without explicit control signals. Design of retention elements for APG is addressed to facilitate safe capturing of circuit states. Experiments with 65-nm technology demonstrate that, compared to standard power gating, total wirelength, and average wiring congestion are reduced by 8.6% and 4.1% on average, respectively, at a cost of 6.8% area increase. In order to fast charge virtual ground rails, a pMOS switch driven by a short pulse is employed to directly provide charges to virtual ground. This helps retention elements avoid short-circuit current while making transition to standby mode. The optimization procedure for sizing pMOS switch and deciding pulse width is addressed, and assessed with 65-nm technology. Experiments show that, compared to standard power gating, APG reduces the delay to enter and exit the standby mode by 65.6% and 28.9%, respectively, with corresponding energy dissipation during the period cut by 46.1% and 36.5%. Standby mode leakage power consumption is also reduced by 15.8% on average.

Soft Error and Soft Delay Mitigation Using Dynamic Threshold Technique

When designers try to address increasing power consumption reduction via optimizations, they need to be aware of the impact on single event robustness. In this work, we examined dynamic threshold MOS-based (DTMOS) schemes for their soft error and soft delay tolerance. Among techniques we considered, the standard DTMOS technique showed the best characteristics in terms of SEU robustness due to increased current drive. We have found that the standard DTMOS technique can be successfully combined with driver sizing approach in mitigating single event transient and soft delay effects. This combined approach results in considerable savings in area compared to driver sizing alone. This is possible since the standard DTMOS gate is more robust to radiation transients compared to a conventional one due to increased critical charge.

Optimization of a highly standardized carboxyfluorescein succinimidyl ester flow cytometry panel and gating strategy design using discriminative information measure evaluation

The design of a panel to identify target cell subsets in flow cytometry can be difficult when specific markers unique to each cell subset do not exist, and a combination of parameters must be used to identify target cells of interest and exclude irrelevant events. Thus, the ability to objectively measure the contribution of a parameter or group of parameters toward target cell identification independent of any gating strategy could be very helpful for both panel design and gating strategy design. In this article, we propose a discriminative information measure evaluation (DIME) based on statistical mixture modeling; DIME is a numerical measure of the contribution of different parameters towards discriminating a target cell subset from all the others derived from the fitted posterior distribution of a Gaussian mixture model. Informally, DIME measures the "usefulness" of each parameter for identifying a target cell subset. We show how DIME provides an objective basis for inclusion or exclusion of specific parameters in a panel, and how ranked sets of such parameters can be used to optimize gating strategies. An illustrative example of the application of DIME to streamline the gating strategy for a highly standardized carboxyfluorescein succinimidyl ester (CFSE) assay is described.

A Novel Variation-Tolerant Keeper Architecture for High-Performance Low-Power Wide Fan-In Dynamic or Gates

Dynamic gates have been excellent choice in the design of high-performance modules in modern microprocessors. The only limitation of dynamic gates is their relatively low noise margin compared to that of standard CMOS gates. Traditionally, this issue has been resolved by employing a pMOS keeper circuit that compensates for leakage current of the pull-down nMOS network. In the earlier technology nodes, the keeper circuit could improve reliability of the dynamic gates with minor performance penalty. However, aggressive scaling trends of CMOS technology along with increasing levels of process variations have reduced effectiveness of the traditional keeper approach. This is because to maintain an acceptable noise margin level in deep sub-100 nm technologies, large pMOS keepers must be employed, which generates substantial contention between the keeper and the pull-down network, and hence results in severe loss of performance and high power consumption. This problem is more severe in wide fan-in dynamic gates due to the large number of leaky nMOS devices connected to the dynamic node. In this paper, a novel variation-tolerant keeper architecture is proposed, which is capable of significantly reducing contention and improving performance and power consumption. Using circuit simulations, the overall improved characteristics of the proposed keeper are demonstrated in comparison to those of the traditional as well as several state-of-the-art keepers. The proposed keeper exhibits the lowest delay deviation under different levels of process variations. Also, it is shown that for an eight-input or gate, in presence of 15% Vth fluctuations, the proposed architecture can lead to 20%, 15%, and more than 40% reduction in power consumption, mean delay, and standard deviation of delay, respectively, when compared to the traditional keeper circuit.

Overlapping-gate architecture for silicon Hall bar field-effect transistors in the low electron density regime

We report the fabrication and study of Hall bar field-effect transistors in which an overlapping-gate architecture allows four-terminal measurements of low-density two-dimensional electron systems while maintaining a high density at the Ohmic contacts. Comparison with devices made using a standard single gate show that measurements can be performed at much lower densities and higher channel resistances, despite a reduced peak mobility. We also observe a voltage threshold shift which we attribute to negative oxide charge, injected during electron-beam lithography processing.

Comparison of HfSiOx Thin Films Deposited by ALD with Moisture Using Different Silicon Sources

The scaling of semiconductor devices using various high-k materials has been investigated, and replacing the standard SiO2 gate dielectric by high-k material was a major step. Hafnium-based material is currently one of the preferred candidates. To improve integration of Hafnium into the gate dielectric, HfSiOx has been chosen for low power devices while HfZrOx is more common for high-performance applications. Using widely available processes, HfO2 can be deposited using amine or alkoxide based compounds and different reducing agents such as ozone, oxygen or moisture. However, depositing HfSiOx by Atomic Layer Deposition (ALD) with moisture is more challenging. Few or no available Silicon precursors are reactive with H2O alone to deposit SiO2 by ALD. This work is intended to present precursor solutions to deposit hafnium silicate using moisture as oxidant.

P3a and P3b of event-related potentials in persons with Asperger disorder

Although numerous research studies have explored the functional attributes of the human duration perception, the spatio- temporal information on cortical networks underlying this process is still an open question. Moreover, the issue of possible differences in the nature of timing mechanisms responsible for perception of sub- and supra-second intervals requires the implementation of the functional brain imaging techniques with both high spatial and temporal resolution. Attention is very frequently used as a modulating factor for the perceived duration of a sensory stimulus. The non-attended stimuli appear to last shorter than the attended ones, increasing the perceived duration of a concurrent stimulus (Gorea, 2011). This study challenges the accepted model of early sensory responses, activated during the first 100 ms after stimulus presentation, as preattentive, automatic processes which modulate the neural sensitivity to incoming stimuli (gating phenomena). We utilized Elekta Neuromag 306-channel whole-head system for magnetoencephalography (MEG) measurements and multi-dipole Calibrated Start Spatio Temporal (CSST) localization technique (Ranken et al., 2002) to investigate whether voluntary attention directed at the second tone of a pair in the standard paired-click paradigm could affect cortical networks underlying the gating out phenomenon. MEG recordings were obtained in a magnetically shielded room at the Biomagnetic Center in Jena, Germany. Two consecutive (ISI=500 ms) identical short tonnes (S1 and S2; duration=20ms; f=1200 Hz; ITI=8±1s) were used to evoke standard gating cortical responses in 19 healthy participants (21-38 years). In the second condition, the task was to direct attention toward the second tone and to respond to a rarely presented non-identical second tone of the pair (R=1300 Hz, p(S1R)=0.3). MEG recordings showed transient early and middle latency responses with peak amplitudes over the temporo-parietal sensors followed by a peak of a sustained activity. Less prominent transient activity was recorded over the frontal sensors, accompanied with a more steady- state component from 100 until 400 ms post-stimulus for both conditions. Preliminary results of the CSST spatio-temporal analyses revealed 4-6 brain regions activated during 20-500 ms time interval including bilateral superior temporal gyrus (STG), bilateral and medial prefrontal (PF), bilateral parietal (PA) regions, and central motor cortex area. A cortical source underlying the steady-state component was identified in the left prefrontal region for S1 tone, and in central posterior regions (PA) for the repeated tone S2. During the standard paradigm the M50 gating suppression was observed only for bilateral STG sources while bilateral PF and PA sources did not show any reduction in the response during the first 100 ms post-stimulus. Targeting the attention towards the second tone enhanced the M50 amplitude of the bilateral STG responses in respect to the repeated stimulus S2 and caused a change in the activated network evident by the emergence of a new generator in the medial PF area (orbitofrontal) instead of dorsolateral PF generators evoked in non-attended condition. These results demonstrate that voluntary attention can exert a topological and functional modulatory influence on the neural network even during early stages of auditory processing.

Electric field distribution in AlGaN/GaN high electron mobility transistors investigated by electroluminescence

Electric field distributions in AlGaN/GaN high electron mobility transistors have been assessed by studying electroluminescence and its spatial intensity distribution. Three gate architectures were compared: (i) standard gate, (ii) slant gate, and (iii) recessed slant gate with fluorination. It was found that differences in peak electric field strengths between devices, determined using electroluminescence, agreed well with simulations. However, recessed slant gate devices with fluorination exhibited a spread of electroluminescence intensity and therefore electric field distribution toward the drain contact by 0.2–0.3 μm which was not predicted by simulation. Implication of the disagreement between measured and simulated electric field distribution are discussed.

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