IC Structures Research Articles

Emerging Blood Gas Monitors: How They Can Help With COVID-19

The world has been in combat with COVID-19 since December 2019. The United States has been paralyzed, with the highest number of cases and more deaths than any other country. However, the disease has devastated almost every nation across the globe, from the Far East to Europe, Latin America, Russia, and India. In this article, we cover emerging blood gas monitoring devices and techniques to create the sensors and IC structures to transform bulky benchtop instruments into miniaturized, next-generation bio-medical devices. We also explore currently available technologies, with a short glance back to the evolution of blood gas sensing systems.

Simplistic approach to alleviate noise coupling issues in 3D IC integration

Through-silicon-via (TSV) technology has emerged as the key technology to enable 3D IC integration. 3D integration is seen as the leading candidate, which can help in sustaining Moore’s Law to future IC technology nodes. It clearly set a benchmark to the IC industry due to its tremendous benefits in performance, data bandwidth, and supports heterogeneous integration. In 3D IC structure TSV’s are used to carry the overall electrical signal between the layers. The major drawback in the TSV based 3D integration is noise coupling between aggressive (electrical signal carrying TSV; ETSV) and victim TSV’s (ground). It can be reduced by creating very good isolation between TSV’s and Si substrate by using different liner materials around TSV’s. In this work, we have addressed various TSV models to reduce noise coupling between the TSV’s. The models we have studied are single layer model and stacked layers of liner model. Apart from this we have studied how the core materials in the TSV reduces noise coupling between aggressive and victim TSV’s. Also, we have shown the high frequency study for proposed models. Finally, our work shows single layer model with Crystalline-Germanium is comparably better noise coupling reduction even at higher frequency.

Effects of the Ion to Growth Flux Ratio on the Constitution and Mechanical Properties of Cr1-x-Alx-N Thin Films.

Cr-Al-N thin film materials libraries were synthesized by combinatorial reactive high power impulse magnetron sputtering (HiPIMS). Different HiPIMS repetition frequencies and peak power densities were applied altering the ion to growth flux ratio. Moreover, time-resolved ion energy distribution functions were measured with a retarding field energy analyzer (RFEA). The plasma properties were measured during the growth of films with different compositions within the materials library and correlated to the resulting film properties such as phase, grain size, texture, indentation modulus, indentation hardness, and residual stress. The influence of the ion to growth flux ratio on the film properties was most significant for films with high Al-content (xAl = 50 at. %). X-ray diffraction with a 2D detector revealed hcp-AlN precipitation starting from Al-concentration xAl ≥ 50 at. %. This precipitation might be related to the kinetically enhanced adatom mobility for a high ratio of ions per deposited atoms, leading to strong intermixing of the deposited species. A structure zone transition, induced by composition and flux ratio JI/JG, from zone T to zone Ic structure was observed which hints toward the conclusion that the combination of increasing flux ratio and Al-concentration lead to opposing trends regarding the increase in homologous temperature.

AM3D: An accurate crosstalk probability modeling to predict channel delay in 3D ICs

Migration from Two Dimensional Integrated Circuits (2D ICs) to Three Dimensional Integrated Circuits (3D ICs) reduces the delay due to the shorter wire length between sender and receiver. However, Through-Silicon-Vias (TSVs) that connect layers in the structure of 3D ICs can seriously increase the delay due to capacitance coupling between TSVs and lead to crosstalk fault. The severity of crosstalk faults depends on transitions appearing on TSVs that is called transition patterns. To propose an efficient crosstalk tackling mechanisms in 3D ICs, an accurate probability analytical model is required to predict the delay caused by TSVs (3D ICs) in the attendance of these transition patterns. In this regard, this paper proposes an accurate crosstalk probability model for 3D ICs called AM3D that estimates the latency of communication channels of 3D ICs in the attendance of crosstalk faults. The model is applicable for both non-protected TSVs and TSVs which are protected by crosstalk mitigation mechanisms. In order to accredit our proposed model, various SPICE simulations are conducted and obtained outcomes in different benchmarks are compared with extracted results from AM3D. Comparisons present an average of 1.81% discrepancies between the time delay obtained from SPICE simulations and time delay calculated by our proposed model.

Multivariate optimization of the pulse electrochemical oxidation for treating recalcitrant dye wastewater

Electrochemical oxidation under pulse current mode was employed to treat bio-refractory dye wastewaters (i.e., Indigo Carmine [IC], Alizarin Red S [ARS], and Methyl Orange [MO]) with PbO2/Ti anode, and Box-Behnken designs (BBDs) were conducted to optimize the operating parameters for enhancing energy efficiencies. Pulse duty cycle, current density, and flow rate of effluent were determined to be the influencing factors for the degradation performance, and analyses of BBDs further revealed that the influencing degrees of these factors follow the order: current density > pulse duty cycle > flow rate for the degradation of IC and MO, but such conclusion is not applicable to that of ARS. the fused-rings structure of ARS is more difficult to be electro-oxidized than the ring-bridge-ring structures of IC and MO. The optimal solutions with the criteria of maximizing TOC degradation and minimizing energy consumption were obtained by the model fitting of BBDs, and with the optimized operating parameters the energy consumptions can be saved up to 35.5%, 40.1%, and 47.9% for IC, ARS, and MO, respectively, as compared with the traditional electrolysis process with galvanostatic mode. Such optimization method can improve the practicability of electrochemical oxidation process. Further investigation of quantitative relationships between the degradation efficiencies and the structures of organic pollutants is believed to help guide parameter optimizing, and such work is currently underway.

Crystal Structure Prediction via Basin-Hopping Global Optimization Employing Tiny Periodic Simulation Cells, with Application to Water-Ice.

A crystal structure prediction algorithm for use in periodic boundary conditions with empirical rigid models is presented, which employs (i) unrestricted cutoff radii for the real-space interactions, thus allowing the treatment of even very small unit cells, and (ii) a global-optimization algorithm based on the basin-hopping method of Wales et al. (D. J. Wales and J. P. K. Doye, J. Phys. Chem. A 1997, 101, 5111). The algorithm is then applied to the TIP4P model of water (W. L. Jorgensen et al., J. Chem. Phys. 1983, 79, 926.) in order to find the lowest enthalpy water-ice crystalline structures in the pressure region 0-8000 bar, in unit cells holding in the range of 1-16 molecules, and a database of the 10 lowest enthalpy structures found at pressures 0, 4000, and 8000 bar is presented. The algorithm finds many of the ice polymorphs and, in particular, finds that the lowest energy structure at zero pressure is almost exactly tied between an ice Ic (cubic ice) and ice Ih (hexagonal ice) structure, having near-identical energies.

Structural evolution of La2Ti2O7 at elevated temperatures.

Structural evolution of a La2Ti2O7 ferroelectric compound possessing perovskite-type slabs at elevated temperatures was investigated using the single-crystal X-ray diffraction technique. The monoclinic low-temperature phase (L) transformed into the orthorhombic high-temperature phase (H) via an incommensurately modulated phase (IC) between ∼989 and ∼1080 K. The L-IC transition was considered to be of the first order, with the L+IC two-phase co-existing region between ∼989 and ∼1027 K. The structure of IC was determined from the (3+1)-dimensional superspace representation with a modulation vector q = αao (α ≃ 0.49), where ao is the a-axis vector of the basic cell. The structural modulation originated from the variation of the tilt angle of the TiO6 octahedra in the perovskite-type slab in association with small positional displacements of La atoms. The IC-H transition took place at ∼1080 K and was close to the second order. During the IC-H transition, nanoscale flat plate domains having either a cell twin of the L-type structural modules or a cell twin of the alternating H- and L-type structural modules began to appear in the approximant structure of IC. The thickness of the flat plate domains then grew rapidly along the modulation vector in proportion to (½ - α)-1 as α approached ½ with decreasing temperature. In the two-phase L+IC co-existing region, the IC phase consisting of the two types of cell twins was gradually replaced with the low-temperature monoclinic phase L, which is not cell twinned but rather twinned macroscopically by the L-type structural modules.

Structural mechanisms of selectivity and gating in anion channelrhodopsins.

Both designed and natural anion-conducting channelrhodopsins (dACRs and nACRs, respectively) have been widely applied in optogenetics (enabling selective inhibition of target-cell activity during animal behaviour studies), but each class exhibits performance limitations, underscoring trade-offs in channel structure-function relationships. Therefore, molecular and structural insights into dACRs and nACRs will be critical not only for understanding the fundamental mechanisms of these light-gated anionchannels, but also to create next-generation optogenetic tools. Here we report crystal structures of the dACR iC++, along with spectroscopic, electrophysiological and computational analyses that provide unexpected insights into pH dependence, substrate recognition, channel gating and ion selectivity of both dACRs and nACRs. These results enabled us to create an anion-conducting channelrhodopsin integrating the key features of large photocurrent and fast kinetics alongside exclusive anion selectivity.

Ab Initio Studies on the Interaction Between Copper(I) and 5-Nitrotetrazolate Anion

<p class="p1">Ab initio molecular orbital calculations on the interaction between Copper(I) and 5-nitrotetrazolate anion were done using different basis sets, at the HF, B3LYP and MP2 levels of theory. Three minima were found to 1A, 1B and IC structures of Cu(I)-5-NTz complex. At the B3LYP/LanL2DZ level, the energy difference between 1A and 1B was computed to be 8.18 kcal/mol, while that between 1A and 1C is 22.76 kcal/mol. The presence of both Cu-N and Cu-O interactions is revealed in 1A structure using both natural bond orbital and atoms-in-molecules analyses, which makes more stable than those of 1B and 1C complexes. The binding energy corrected for both ZPE and BSSE for 1A is found to be -150.59 kcal/mol at the B3LYP/LanL2DZ level. The barrier for the 1B <span class="s1">→</span> 1A and 1C <span class="s1">→</span> 1B conversion is calculated to be 7.80 kcal/mol and 9.40 kcal/mol, respectively.</p>

Maximum Radiated Emissions Evaluation for the Heatsink/IC Structure Using the Measured Near Electrical Field

Creating an equivalent field source is an efficient method for predicting radiated emissions from IC structures. In this paper, the maximum radiated emissions for a heat-sink/IC structure is predicted by creating an equivalent source from the measured electrical field (E-field) in the gap between the heatsink and IC. The E-field is detected by an E-field probe made of an open coaxial cable coated with absorbing material. A numerical model is built in the computer simulation technology microwave studio to obtain the maximum radiated field, where the measured E-field is used as a source to excite the heat-sink model. The evaluated maximum radiated field is in good agreement with the measured value; the error is within 7 dB up to 40 GHz for the source with phase, and 7 dB up to 10 GHz for the phaseless measurement.

Smart Power Devices and ICs Using GaAs and Wide and Extreme Bandgap Semiconductors

We evaluate and compare the performance and potential of GaAs and of wide and extreme bandgap semiconductors (SiC, GaN, Ga2O3, and diamond), relative to silicon, for power electronics applications. We examine their device structures and associated materials/process technologies and selectively review the recent experimental demonstrations of high voltage power devices and IC structures of these semiconductors. We discuss the technical obstacles that still need to be addressed and overcome before large-scale commercialization commences.

Influence of Material Properties on the Fluid-Structure Interaction aspects during Molded Underfill Process

This paper presents the investigation of the effects of epoxy moulding compound’ (EMC) viscosity on the FSI aspects during moulded underfill process (MUF). Finite volume (FV) code and finite element (FE) code were connected online through the Mesh-based Parallel Code Coupling Interface (MpCCI) method for fluid and structural analysis. The EMC flow behaviour was modelled by Castro-Macosko model, which was written in C language and incorporated into the FV analysis. Real-time predictions on the flow front, chip deformation and stress concentration were solved by FV- and FE-solver. Increase in EMC viscosity raises the deformation and stress imposed on IC and solder bump, which may induce unintended features on the IC structure. The current simulation is expected to provide the better understandings and clear visualization of FSI in the moulded underfill process.

Magnetic field structure of IC 63 and IC 59 associated with H ii region Sh 185

Bright-rimmed clouds (BRCs) are formed at the periphery of H$~$II regions as the radiation from the central star interacts with dense gas. The ionization and resulting compression of the clouds may lead to cloud disruption causing secondary star formation depending on the stellar and gas parameters. Here we use R-band polarimetry to probe the plane-of-the sky magnetic field in the two near-by BRCs IC\,59 and IC\,63. Both nebulae are illuminated by $\gamma$ Cas with the direction of ionizing radiation being orientated parallel or perpendicular to the local magnetic field, allowing us to probe the importance of magnetic field pressure in the evolution of BRCs. Because of the proximity of the system ($\sim$200pc) we have acquired a substantial sample of over 500 polarization measurements for stars background to the nebulae. On large scales, the magnetic field geometries of both clouds are anchored to the ambient magnetic field. For IC 63, the magnetic field is aligned parallel to the head-tail morphology of the main condensation, with convex morphology relative to the direction of the ionizing radiation. We estimate the plane of the sky magnetic field strength in IC\,63 to be $\sim90\mu$G. In IC\,59, the projected magnetic field follows the M shape morphology of the cloud. Here, field lines present a concave shape with respect to the direction of the ionizing radiation from $\gamma$ Cas. Comparing our observations to published theoretical models we find good general agreement, supporting the importance of magnetic fields in BRC evolution.

Thermophysical and Geometrical Effects on the Thermal Performance and Optimization of a Three-Dimensional Integrated Circuit

A comprehensive analysis and optimization of a three-dimensional integrated circuit (3D IC) structure and its thermophysical attributes are presented in this work. The thermophysical and geometrical attributes studied in this paper include the die, device layer, heat sink, and heat spreader, which are critical structures within a 3D IC. The effect of the power density of the device layer which is the source of heat generation within the chip as well as the through silicon vias (TSV) and microbumps is also considered in our investigation. The thermophysical and geometrical parameters that have a significant impact on the thermal signature of the 3D IC as well as those that have an insignificant impact were established. The comprehensive analysis of different geometrical and thermophysical attributes can guide the design and optimization of a 3D IC structure and decrease the cost.

Simulation of ESD Thermal Failures and Protection Strategies on System Level

In this paper, approaches for the modeling and simulation of thermal destruction of ICs due to ESD are discussed from a system point of view. Considered systems consist of ESD generator, PCB, protection element, and IC. A direct connection between the ESD generator and the system is always assumed. For the modeling of an IC ESD destruction, the electric behavior model of an IC pin to ground or supply is extended with a thermal destruction model. The thermal model consists mainly of a thermal resistance and a thermal capacitance. When structure temperature reaches a threshold, a failure is assumed. All needed model parameters can be found with a set of measurements and tests. No internal knowledge of the IC or protection element structures is required. The methodology was applied to several ICs, protection elements, and system structures with emphasis on automotive electronics. All needed component model parameters were generated from measurements. Models and parameter measurements are described. Results from the system simulation were compared to system test results with hardware. In most cases, the simulation could predict well the destruction behavior of a system. Thermal failure and safe operating area prediction quality are compared. The described simulation method helps with selection of protection strategies and optimization of system ESD robustness.

Competition between ices Ih and Ic in homogeneous water freezing.

The role of cubic ice, ice Ic, in the nucleation of ice from supercooled water has been widely debated in the past decade. Computer simulations can provide insightful information about the mechanism of ice nucleation at a molecular scale. In this work, we use molecular dynamics to study the competition between ice Ic and hexagonal ice, ice Ih, in the process of ice nucleation. Using a seeding approach, in which classical nucleation theory is combined with simulations of ice clusters embedded in supercooled water, we estimate the nucleation rate of ice for a pathway in which the critical nucleus has an Ic structure. Comparing our results with those previously obtained for ice Ih [Sanz et al., J. Am. Chem. Soc. 135, 15008 (2013)], we conclude that within the accuracy of our calculations both nucleation pathways have the same rate for the studied water models (TIP4P/Ice and TIP4P/2005). We examine in detail the factors that contribute to the nucleation rate and find that the chemical potential difference with the fluid, the attachment rate of particles to the cluster, and the ice-water interfacial free energy are the same within the estimated margin of error for both ice polymorphs. Furthermore, we study the morphology of the ice clusters and conclude that they have a spherical shape.

Novel AlInN/GaN integrated circuits operating up to 500 °C

High electron concentration in 2DEG channel of AlInN/GaN devices is remarkably stable over a broad temperature range, enabling device operation above 500°C. The developed IC technology is based on three key elements: (1) exceptional quality AlInN/GaN heterostructure with very high carrier concentration and mobility enables IC fast operation in a broad temperature range; (2) heterostructure field effect transistor approach t provides fully planar IC structure which is easy to scale and to combine with the other high temperature electronic components; (3) fabrication advancements including novel metallization scheme and high-K passivation/gate dielectrics enable high temperature operation. The feasibility of the developed technology was confirmed by fabrication and testing of the high temperature inverter and differential amplifier ICs using AlInN/GaN heterostructures. The developed ICs showed stable performance with unit-gain bandwidth above 1MHz and internal response time 45ns at temperatures as high as 500°C.

Through the Looking Glass?The 2015 Edition: Trends in Solid-State Circuits from ISSCC

The International Solid-State Circuits Conference (ISSCC) is the flagship conference of the IEEE Solid-State Circuits Society. This year, for ISSCC, the theme is ?Silicon Systems: Small Chips for Big Data.? Big data is enveloping us: it is being generated by the Internet-of-Things (IoT), health care, and the Web, changing our society and our individual lives. Small silicon chips enable these changes through data sensing, gathering, processing, storing, and networking through wireless and wireline connectivity. Recent silicon-?system technologies, including ultra-low-power systems, high-performance circuits and systems, wireless power and data transmission, and three-dimensional (3-D) IC structures, will open the door to big data applications. Moreover, big data applications such as health care, machine learning, and sensor systems will challenge designers to consider new system architectures requiring advances in circuits and technology. ISSCC 2015 showcases novel circuit and system solutions that open new vistas for society, providing opportunities for new lifestyle transformations, all driven by big data technology.

An Efficient Method to Extract Surface-Wave Poles of Green's Functions Near Branch Cut in Lossy Layered Media

Calculating the Green's functions in lossy layered media using the discrete complex image method (DCIM) is challenging, due to the difficulties in extracting the surface-wave poles that are very close to a branch cut. An efficient algorithm based on the contour method is proposed in this communication to locate these poles and calculate the residues. The proposed method is robust for both the lossless and lossy media. With the proposed approach, it is shown in numerical examples that some poles, very close to a branch cut, are successfully extracted in lossy media. The accurate calculation of the Green's functions in lossy layered media enables the accurate and efficient modeling of complex structures in lossy semiconductor substrates and new 3D IC structures including through-silicon vias (TSVs).

EUV Lithography를 위한 진공 기술

Lithography is widely recognized as one of the key steps in the manufacture of ICs and other devices and/or structures. However, as the dimensions of features made using lithography become smaller, lithography is becoming a more critical factor for enabling miniature IC or other devices and/or structures to be manufactured. As explained above, to make it happen, many other important technologies will have to be addressed. The vacuum technology is one of them and the engineers and experts are paying attention on vacuum technology including vacuum pumps. Especially high Vacuum(HV) and Ultra high vacuum(UHV) are not easy and not simple one. So the manpower who can understand vacuum technology with long experience in vacuum industry is important with basic study.