Impact of Complex-Logic Cell Layout on the Single-Event Transient Sensitivity

International audienceThe design methodology based on standard cells is widely used in a broad range of VLSI applications. Further, several optimization algorithms can be employed to address different constraints such as power consumption or reliability. This work evaluates the implications of the usage of complex-logic cells from a 45 nm Standard-Cell library to the Single-Event Transient sensitivity under heavy ions. Results show that even though a reduction in the layout area is obtained when adopting complex-logic gates, a slight reduction in the total sensitive area of the circuit is observed. Moreover, the effectiveness of logical masking can be suppressed, leading to a higher SET cross-section

Monte Carlo simulation of particle-induced bit upsets

We investigate the issue of radiation-induced failures in electronic devices by developing a Monte Carlo tool called MC-Oracle. It is able to transport the particles in device, to calculate the energy deposited in the sensitive region of the device and to calculate the transient current induced by the primary particle and the secondary particles produced during nuclear reactions. We compare our simulation results with SRAM experiments irradiated with neutrons, protons and ions. The agreement is very good and shows that it is possible to predict the soft error rate (SER) for a given device in a given environment

Prognostic impact of multidrug resistance gene expression on the management of breast cancer in the context of adjuvant therapy based on a series of 171 patients

Study of the prognostic impact of multidrug resistance gene expression in the management of breast cancer in the context of adjuvant therapy. This study involved 171 patients treated by surgery, adjuvant chemotherapy±radiotherapy±hormonal therapy (mean follow-up: 55 months). We studied the expression of multidrug resistance gene 1 (MDR1), multidrug resistance-associated protein (MRP1), and glutathione-S-transferase P1 (GSTP1) using a standardised, semiquantitative rt–PCR method performed on frozen samples of breast cancer tissue. Patients were classified as presenting low or high levels of expression of these three genes. rt-PCR values were correlated with T stage, N stage, Scarff–Bloom–Richardson (SBR) grade, age and hormonal status. The impact of gene expression levels on 5-year disease-free survival (DFS) and overall survival (OS) was studied by univariate and multivariate Cox analysis. No statistically significant correlation was demonstrated between MDR1, MRP1 and GSTP1 expressions. On univariate analysis, DFS was significantly decreased in a context of low GSTP1 expression (P=0.0005) and high SBR grade (P=0.003), size ⩾5 cm (P=0.038), high T stage (P=0.013), presence of intravascular embolus (P=0.034), and >3 N+ (P=0.05). On multivariate analysis, GSTP1 expression and the presence of ER remained independent prognostic factors for DFS. GSTP1 expression did not affect OS. The levels of MDR1 and MRP1 expression had no significant influence on DFS or OS. GSTP1 expression can be considered to be an independent prognostic factor for DFS in patients receiving adjuvant chemotherapy for breast cancer

Soft Error Triggering Criterion Based on Simple Electrical Model of the SRAM cell

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Neutron-Induced Failures of Trench Gate Fieldstop IGBT

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Alpha particle-induced transient currents in 65 nm and 40 nm technologies

International audienceSome radionuclides are known to spontaneously emit alpha particles, which have been identified as a reliability issue in microelectronics. Despite their low stopping powers (<1.45 MeV / (mg/cm2) in silicon), these alpha particles are able to trigger Single Event Transient (SET) and Single Event Upset (SEU) in modern technologies and it is useful to evaluate the effect of alpha emitters on the Soft Error Rate (SER). The radionuclides that are likely to be introduced during semiconductor processing have been previously identified. Here, we focus on the decay chain of Uranium 238 which is very abundant in nature and thus in the raw materials that can be used for microelectronics processing. Uranium 238 chain contains 8 radiaoactive nuclei which produce alpha particles. Along their paths the alpha particles are able to generate electron-hole pairs, which diffuse and may lead to transient currents that affect directly the device reliability. In order to accurately evaluate the reliability of a given device, it is mandatory to understand in detail the main properties of the transient currents (e.g. the shape) that are generated during particle emission. It has already been asserted that a double exponential law can model the shape of the transient current, but it is a priori difficult to determine the values of the parameters of this law. Moreover, these parameters strongly depend on the technology as well as the nature and energy of the ionizing particle. Focusing on the Uranium decay chain we investigated the pollution of the bulk and the properties of the transient currents which are generated at an electrode of a 65 nm and a 40 nm technologies. To do so, we used a Monte Carlo approach. The simulated structure is a silicon layer with a surface of 30 µm x 30 µm and a thickness of 20 µm. Above this bulk, we added a layer of 10 µm of silicon dioxide to account for the Back End Of Line (BEOL). At the Si/SiO2 interface, we simulate 12 x 12 drain electrodes whose characteristic dimensions are extrapolated from actual sequential logic circuits implemented with 65 nm and 40 nm technologies. Then we trigger alpha emission at random in the structure assuming that the contamination is uniform. We assume the secular equilibrium for the decay chain which means that even if the concentrations of the emitters are different, their activities are equal. The concentration of the Uranium 238 nucleus is typically around 100 ppt after recent works. Then its activity is easily obtained. Following the alpha particle along its path, we use the diffusion law model to determine how the carrier concentrations vary in space and time. We then numerically divide the ion track into small fragments that spherically diffuse their charges which are calculated using SRIM results. A portion of these electrical charges is collected by the drain electrode that is itself divided into elemental sections. The integration of the collected charge along the whole track and over the whole drain surface gives the final current pulse. A high number of disintegrations is chosen to have a good enough statistic. Yet, because the critical charge is typically above 0.5-1 fC for the investigated technologies, we trigger enough disintegration to have hundreds of transient pulses for which the total collected charge is higher than 0.5 fC. Finally, we present the characteristics of these pulses such as their amplitude and full width at medium height. It allows having guidelines on the kind of transient pulses that can be produced by alpha particles

Comparison of the transient current shapes obtained with the diffusion model and the double exponential law &#x2014; Impact on the SER

International audienceWe calculated neutron induced Single Event Upset (SEU) cross-section as well as the Soft Error Rate (SER) at ground level. For this purpose, we first used an accurate model based on simulation of atmospheric neutron-induced transient currents in a 90-nm drain electrode, through a detailed diffusion model. Then, we performed the same simulations by replacing each transient current by a simple double exponential law model, for which the parameters were set in order to keep the same total charge as for the diffusion model, as well as the same value of maximum current and its corresponding occurrence time. Our results show a little increase of the cross section while using the double exponential law and we established a correlation between the parameters characterizing the double exponential and the diffusion model curves

Global Trends in the Innovation and Diffusion of Climate Change Mitigation Technologies

Increasing the development and diffusion of low-carbon technologies on a global scale is critical to mitigating climate change. Based on over two million patents from 1995 to 2017 from 106 countries in all major climate mitigation technologies, our analysis shows an annual average low-carbon patenting growth rate of 10 percent from 1995 to 2013. Yet, from 2013 to 2017 low-carbon patenting rates have fallen by around 6 percent annually, likely driven by declining fossil fuel prices and, possibly, a readjustment of investors’ expectations and a stagnation of public funding for green R&D after the financial crisis. The Paris Agreement does not appear to have reversed the negative trend in low-carbon patenting observed since 2013. Innovation is still highly concentrated, with Germany, Japan, and the US accounting for more than half of global inventions, and the top 10 countries for around 90%. This concentration has further intensified over the last decade. Except for China, emerging economies have not caught up and remain less specialised in low-carbon technologies than the world average. This underscores the need for more technology transfers to developing and emerging economies, where most of the future CO2-emissions increases are set to occur. Existing transfer mechanisms, such as the UN Technology Transfer Mechanism and the Clean Development Mechanism, appear insufficient given the slow progress of technology transfer

Global trends in the invention and diffusion of climate change mitigation technologies

Increasing the development and diffusion of climate change mitigation technologies on a global scale is critical to reaching net-zero emissions. We have analysed over a quarter of a million high-value inventions in all major climate change mitigation technologies patented from 1995 to 2017 by inventors located in 170 countries. Our analysis shows an annual growth rate of 10% from 1995 to 2012 in these high-value inventions. Yet, from 2013 to 2017, the growth rate of these inventions fell by around 6% annually, likely driven by declining fossil fuel prices, low carbon prices and increasing technological maturity for some technologies, such as solar photovoltaics. Invention has remained highly concentrated geographically over the past decade, with inventors in Germany, Japan and the United States accounting for more than half of global inventions, and the top ten countries for almost 90%. Except for inventors in China, most middle-income economies have not caught up and remain less specialized in low-carbon technologies than high-income economies

A Simple Method for Assessing Power Devices Sensitivity to SEEs in Atmospheric Environment

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