Modelling of ionization effects and the effects of displacement in digital chips for CAD

10.12737/8491 ◽  
2015 ◽  
Vol 4 (4) ◽  
pp. 280-290 ◽  
Author(s):  
Ачкасов ◽  
V. Achkasov ◽  
Чевычелов ◽  
Yu. Chevychelov ◽  
Анциферова ◽  
...  

The methods of design of digital fault-tolerant bipolar integrated circuits to exposure to radiations such as gamma, x-ray and neutron radiation are considered, as well as the impact of the neutron pulse, which af-fect largely on the gain of the transistor. The operating mode of integrated circuits with change in the ini-tial values of voltages, as well as currents of the emitter and of the base is presented. Numerical calcula-tions of the ionization current in the base-collector junction are considered which allow pre-calculate dose rate of gamma, x-ray and neutron radiation.

10.12737/8494 ◽  
2015 ◽  
Vol 4 (4) ◽  
pp. 291-300 ◽  
Author(s):  
Ачкасов ◽  
V. Achkasov ◽  
Чевычелов ◽  
Yu. Chevychelov ◽  
Анциферова ◽  
...  

The technique of radiation-resistant design of integrated circuits in computer-aided design is presented and comparisons with expert data are provided, which are affected by these types of radiations like gam-ma, x-ray and neutron radiation, as well as the impact of the neutron pulse, which affect largely, on the gain of the transistor are examined. Different types of cardinality doses are represented that affect the crystals of integrated circuits based on the real pulse shape of artificial intelligence.


Author(s):  
Halit Dogan ◽  
Md Mahbub Alam ◽  
Navid Asadizanjani ◽  
Sina Shahbazmohamadi ◽  
Domenic Forte ◽  
...  

Abstract X-ray tomography is a promising technique that can provide micron level, internal structure, and three dimensional (3D) information of an integrated circuit (IC) component without the need for serial sectioning or decapsulation. This is especially useful for counterfeit IC detection as demonstrated by recent work. Although the components remain physically intact during tomography, the effect of radiation on the electrical functionality is not yet fully investigated. In this paper we analyze the impact of X-ray tomography on the reliability of ICs with different fabrication technologies. We perform a 3D imaging using an advanced X-ray machine on Intel flash memories, Macronix flash memories, Xilinx Spartan 3 and Spartan 6 FPGAs. Electrical functionalities are then tested in a systematic procedure after each round of tomography to estimate the impact of X-ray on Flash erase time, read margin, and program operation, and the frequencies of ring oscillators in the FPGAs. A major finding is that erase times for flash memories of older technology are significantly degraded when exposed to tomography, eventually resulting in failure. However, the flash and Xilinx FPGAs of newer technologies seem less sensitive to tomography, as only minor degradations are observed. Further, we did not identify permanent failures for any chips in the time needed to perform tomography for counterfeit detection (approximately 2 hours).


2015 ◽  
Vol 44 (1) ◽  
pp. 22-26 ◽  
Author(s):  
P. K. Skorobogatov ◽  
A. V. Sogoyan ◽  
G. G. Davydov ◽  
A. N. Egorov ◽  
D. V. Savchenkov

2014 ◽  
Vol 12 ◽  
pp. 187-195 ◽  
Author(s):  
J. Geldmacher ◽  
J. Götze

Abstract. This paper investigates the impact of an error-prone buffer memory on a channel decoder as employed in modern digital communication systems. On one hand this work is motivated by the fact that energy efficient decoder implementations may not only be achieved by optimizations on algorithmic level, but also by chip-level modifications. One of such modifications is so called aggressive voltage scaling of buffer memories, which, while achieving reduced power consumption, also injects errors into the likelihood values used during the decoding process. On the other hand, it has been recognized that the ongoing increase of integration density with smaller structures makes integrated circuits more sensitive to process variations during manufacturing, and to voltage and temperature variations. This may lead to a paradigm shift from 100 %-reliable operation to fault tolerant signal processing. Both reasons are the motivation to discuss the required co-design of algorithms and underlying circuits. For an error-prone receive buffer of a Turbo decoder the influence of quantizer design and index assignment on the error resilience of the decoding algorithm is discussed. It is shown that a suitable design of both enables a compensation of hardware induced bits errors with rates up to 1 % without increasing the computational complexity of the decoder.


Author(s):  
Ching-Lang Chiang ◽  
Neeraj Khurana ◽  
Daniel T. Hurley ◽  
Ken Teasdale

Abstract Backside emission microscopy on heavily doped substrate materials was analyzed from the viewpoint of optical absorption by the substrate and sample preparation technique. Although it was widely believed that silicon is transparent to infrared (IR) radiation, we demonstrated by using published absorption data that silicon with doping levels above 5 x 1018cm-3 is virtually opaque, leaving only a narrow transmission window around the energy bandgap. Because the transmission depends exponentially on the thickness of die, thinning to below 100µm is shown to be required. Even an advanced IR sensor such as HgCdTe would find little light to detect without thinning the die. For imaging the circuit, an IR laser-based system produced poor images in which the diffraction patterns often ruined the contrast and obscured the image. Hence, a precise, controlled die thinning technique is required both for emission detection and backside imaging. A thinning and polishing technique was briefly described that was believed to be applicable to most ceramic packages. A software technique was employed to solve the image quality problem commonly encountered in backside imaging applications using traditional microscope light source and a scientific grade CCD camera. Finally, we showed the impact of die thickness on imaging circuits on a heavily doped n type substrate.


Author(s):  
Apangshu Das ◽  
Sambhu Nath Pradhan

Background: Output polarity of the sub-function is generally considered to reduce the area and power of a circuit at the two-level realization. Along with area and power, the power-density is also one of the significant parameter which needs to be consider, because power-density directly converges to circuit temperature. More than 50% of the modern day integrated circuits are damaged due to excessive overheating. Methods: This work demonstrates the impact of efficient power density based logic synthesis (in the form of suitable polarity selection of sub-function of Programmable Logic Arrays (PLAs) for its multilevel realization) for the reduction of temperature. Two-level PLA optimization using output polarity selection is considered first and compared with other existing techniques and then And-Invert Graphs (AIG) based multi-level realization has been considered to overcome the redundant solution generated in two-level synthesis. AIG nodes and associated power dissipation can be reduced by rewriting, refactoring and balancing technique. Reduction of nodes leads to the reduction of the area but on the contrary increases power and power density of the circuit. A meta-heuristic search approach i.e., Nondominated Sorting Genetic Algorithm-II (NSGA-II) is proposed to select the suitable output polarity of PLA sub-functions for its optimal realization. Results: Best power density based solution saves up to 8.29% power density compared to ‘espresso – dopo’ based solutions. Around 9.57% saving in area and 9.67% saving in power (switching activity) are obtained with respect to ‘espresso’ based solution using NSGA-II. Conclusion: Suitable output polarity realized circuit is converted into multi-level AIG structure and synthesized to overcome the redundant solution at the two-level circuit. It is observed that with the increase in power density, the temperature of a particular circuit is also increases.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Matthew G. Hanson ◽  
Barry Chan

Abstract Background Symptomatic pericardial effusion (PCE) presents with non-specific features and are often missed on the initial physical exam, chest X-ray (CXR), and electrocardiogram (ECG). In extreme cases, misdiagnosis can evolve into decompensated cardiac tamponade, a life-threatening obstructive shock. The purpose of this study is to evaluate the impact of point-of-care ultrasound (POCUS) on the diagnosis and therapeutic intervention of clinically significant PCE. Methods In a retrospective chart review, we looked at all patients between 2002 and 2018 at a major Canadian academic hospital who had a pericardiocentesis for clinically significant PCE. We extracted the rate of presenting complaints, physical exam findings, X-ray findings, ECG findings, time-to-diagnosis, and time-to-pericardiocentesis and how these were impacted by POCUS. Results The most common presenting symptom was dyspnea (64%) and the average systolic blood pressure (SBP) was 120 mmHg. 86% of people presenting had an effusion > 1 cm, and 89% were circumferential on departmental echocardiogram (ECHO) with 64% having evidence of right atrial systolic collapse and 58% with early diastolic right ventricular collapse. The average time-to-diagnosis with POCUS was 5.9 h compared to > 12 h with other imaging including departmental ECHO. Those who had the PCE identified by POCUS had an average time-to-pericardiocentesis of 28.1 h compared to > 48 h with other diagnostic modalities. Conclusion POCUS expedites the diagnosis of symptomatic PCE given its non-specific clinical findings which, in turn, may accelerate the time-to-intervention.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2212
Author(s):  
Worawat Poltabtim ◽  
Ekachai Wimolmala ◽  
Teerasak Markpin ◽  
Narongrit Sombatsompop ◽  
Vichai Rosarpitak ◽  
...  

The potential utilization of wood/polyvinyl chloride (WPVC) composites containing an X-ray protective filler, namely bismuth oxide (Bi2O3) particles, was investigated as novel, safe, and environmentally friendly X-ray shielding materials. The wood and Bi2O3 contents used in this work varied from 20 to 40 parts per hundred parts of PVC by weight (pph) and from 0 to 25, 50, 75, and 100 pph, respectively. The study considered X-ray shielding, mechanical, density, water absorption, and morphological properties. The results showed that the overall X-ray shielding parameters, namely the linear attenuation coefficient (µ), mass attenuation coefficient (µm), and lead equivalent thickness (Pbeq), of the WPVC composites increased with increasing Bi2O3 contents but slightly decreased at higher wood contents (40 pph). Furthermore, comparative Pbeq values between the wood/PVC composites and similar commercial X-ray shielding boards indicated that the recommended Bi2O3 contents for the 20 pph (40 ph) wood/PVC composites were 35, 85, and 40 pph (40, 100, and 45 pph) for the attenuation of 60, 100, and 150-kV X-rays, respectively. In addition, the increased Bi2O3 contents in the WPVC composites enhanced the Izod impact strength, hardness (Shore D), and density, but reduced water absorption. On the other hand, the increased wood contents increased the impact strength, hardness (Shore D), and water absorption but lowered the density of the composites. The overall results suggested that the developed WPVC composites had great potential to be used as effective X-ray shielding materials with Bi2O3 acting as a suitable X-ray protective filler.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mikolaj Grabowski ◽  
Ewa Grzanka ◽  
Szymon Grzanka ◽  
Artur Lachowski ◽  
Julita Smalc-Koziorowska ◽  
...  

AbstractThe aim of this paper is to give an experimental evidence that point defects (most probably gallium vacancies) induce decomposition of InGaN quantum wells (QWs) at high temperatures. In the experiment performed, we implanted GaN:Si/sapphire substrates with helium ions in order to introduce a high density of point defects. Then, we grew InGaN QWs on such substrates at temperature of 730 °C, what caused elimination of most (but not all) of the implantation-induced point defects expanding the crystal lattice. The InGaN QWs were almost identical to those grown on unimplanted GaN substrates. In the next step of the experiment, we annealed samples grown on unimplanted and implanted GaN at temperatures of 900 °C, 920 °C and 940 °C for half an hour. The samples were examined using Photoluminescence, X-ray Diffraction and Transmission Electron Microscopy. We found out that the decomposition of InGaN QWs started at lower temperatures for the samples grown on the implanted GaN substrates what provides a strong experimental support that point defects play important role in InGaN decomposition at high temperatures.


Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 381
Author(s):  
Gautier Cesbron-Lavau ◽  
Aurélie Goux ◽  
Fiona Atkinson ◽  
Alexandra Meynier ◽  
Sophie Vinoy

During processing of cereal-based food products, starch undergoes dramatic changes. The objective of this work was to evaluate the impact of food processing on the starch digestibility profile of cereal-based foods using advanced imaging techniques, and to determine the effect of preserving starch in its native, slowly digestible form on its in vivo metabolic fate. Four different food products using different processing technologies were evaluated: extruded products, rusks, soft-baked cakes, and rotary-molded biscuits. Imaging techniques (X-ray diffraction, micro-X-ray microtomography, and electronic microscopy) were used to investigate changes in slowly digestible starch (SDS) structure that occurred during these different food processing technologies. For in vivo evaluation, International Standards for glycemic index (GI) methodology were applied on 12 healthy subjects. Rotary molding preserved starch in its intact form and resulted in the highest SDS content (28 g/100 g) and a significantly lower glycemic and insulinemic response, while the three other technologies resulted in SDS contents below 3 g/100 g. These low SDS values were due to greater disruption of the starch structure, which translated to a shift from a crystalline structure to an amorphous one. Modulation of postprandial glycemia, through starch digestibility modulation, is a meaningful target for the prevention of metabolic diseases.


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