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Flexible multiplexing chips that permit reconfigurable multidimensional channel utilization are indispensable for revolutionary 6G terahertz communications, but the insufficient manipulation capability of terahertz waves prevents their practical implementation. Herein, we propose the first experimental demonstration of a flexible multiplexing chip for terahertz communication by revealing the unique mechanism of topological phase (TP) transition and perseveration in a heterogeneously coupled bilayer valley Hall topological photonic system. The synthetic and individual TPs operated in the coupled and decoupled states enable controllable on-chip modular TP transitions and subchannel switching. Two time-frequency interleaved subchannels support 10- and 12-Gbit/s QAM-16 high-speed data streams along corresponding paths over carriers of 120 and 130 GHz with 2.5- and 3-GHz bandwidths, respectively. This work unlocks interlayer heterogeneous TPs for inspiring ingenious on-chip terahertz-wave regulation, allowing functionality-reconfigurable, compactly integrated and CMOS-compatible chips. [ABSTRACT FROM AUTHOR]

The transport of nutrients, xenobiotics, and signaling molecules across biological membranes is essential for life. As gatekeepers of cells, membrane proteins and nanopores are key targets in pharmaceutical research and industry. Multiple techniques help in elucidating, utilizing, or mimicking the function of biological membrane-embedded nanodevices. In particular, the use of DNA origami to construct simple nanopores based on the predictable folding of nucleotides provides a promising direction for innovative sensing and sequencing approaches. Knowledge of translocation characteristics is crucial to link structural design with function. Here, we summarize recent developments and compare features of membrane-embedded nanopores with solid-state analogues. We also describe how their translocation properties are characterized by microchip systems. The recently developed silicon chips, comprising solid-state nanopores of 80 nm connecting femtoliter cavities in combination with vesicle spreading and formation of nanopore-suspended membranes, will pave the way to characterize translocation properties of nanopores and membrane proteins in high-throughput and at single-transporter resolution.

An overview of recent advances in solid-state cooling utilizing thin-film silicon, germanium-based microrefrigerators is given. Key parameters affecting micro cooler performance are described. A 3-mum thick 200 x (3 nm Si/12 mn Si0.75Ge0.25) superlattice device can achieve maximum cooling of 4 degreesC at room temperature, maximum cooling power density of 600 W/cm(2) for 40-mum diameter device and fast transient response on the order of tens of micro-seconds independent of the device size. Three-dimensional electrothermal simulations show that individual microrefrigerators could be used to remove hot spots in silicon chips with minimal increase in the overall power dissipation.

The clamping force is the most important parameter of Press Pack IGBTs (PP IGBTs) as it not only affects the electrical, thermal, and mechanical characteristic, but also the long lifetime reliability. Too little clamping force increases the contact resistance and junction temperature. Too much clamping force makes the silicon chips mechanical damage. However, it is quite complex and time-consuming to obtain the influence of the clamping force on the long-time reliability through the power cycling test because that many tests are needed to execute under a large range of clamping forces. Here, a single IGBT chip sub-module is proposed to simulate the long lifetime reliability through the finite element method under various clamping forces. Both the thermal contact resistance within different contact interfaces that affects the junction temperature of silicon chips a lot and the elastic-plastic model that affects the lifetime of specific material layers are considered in this finite element model to make it more accurate. The combination of Coffin–Mason and Basquin model is proposed to obtain the power cycling lifetime of the sub-module based on simulation results. A clamping force range is obtained and this also gives a guideline for the power cycling test. [ABSTRACT FROM AUTHOR]

The clamping force is the most important parameter of Press Pack IGBTs (PP IGBTs) as it not only affects the electrical, thermal, and mechanical characteristic, but also the long lifetime reliability. Too little clamping force increases the contact resistance and junction temperature. Too much clamping force makes the silicon chips mechanical damage. However, it is quite complex and time-consuming to obtain the influence of the clamping force on the long-time reliability through the power cycling test because that many tests are needed to execute under a large range of clamping forces. Here, a single IGBT chip sub-module is proposed to simulate the long lifetime reliability through the finite element method under various clamping forces. Both the thermal contact resistance within different contact interfaces that affects the junction temperature of silicon chips a lot and the elastic-plastic model that affects the lifetime of specific material layers are considered in this finite element model to make it more accurate. The combination of Coffin–Mason and Basquin model is proposed to obtain the power cycling lifetime of the sub-module based on simulation results. A clamping force range is obtained and this also gives a guideline for the power cycling test.

When “others” (such as women and people of color) make innovative contributions in scientific and technical fields, they often “disappear” from later history and their contributions are ascribed elsewhere. This is seldom deliberate—rather, it’s a result of the accumulation of advantage by those who are expected to innovate. This article chronicles an example of such a disappearance and introduces the Conway Effect to elucidate the disappearance process. [ABSTRACT FROM AUTHOR]

This study describes the design and evaluation of a secure chip design module for graduate students and junior engineers with electronics and computer engineering. This course has two broad goals, the first is to teach students how design complex systems on chips using industry standard tools and the second is to educate them on emerging hardware security threats and countermeasures. There are a number of strategies currently been employed to handle the rising complexity of chip design, namely reuse, abstraction and automation. The authors aim to show how to employ these approaches to produce working systems within a time‐constrained environment similar to that of IC design companies. One of the unique features of this module is its approach of treating hardware security as an integral part of the chip design process and as one of the design metrics which can be evaluated and optimised, this allows students to better understand the root causes of this issue and to think more constructively about potential countermeasures. The course is designed based on the principles of constructive alignment method and Kolb learning cycle. Detailed syllabus and assessment exercises are included. Feedback results from students' surveys indicate that the module has been positively received. [ABSTRACT FROM AUTHOR]

A recently developed transfer printing technique, laser-driven noncontact microtransfer printing, which involves laser-induced heating to initiate the separation at the interface between the elastomeric stamp (e.g., polydimethylsiloxane (PDMS)) and hard micro/nanomaterials (e.g., Si chip), is valuable to develop advanced engineering systems such as stretchable and curvilinear electronics. The previous thermomechanical model has identified the delamination mechanism successfully. However, that model is not valid for small-size Si chip because the size effect is ignored for simplification in the derivation of the crack tip energy release rate. This paper establishes an accurate interfacial fracture mechanics model accounting for the size effect of the Si chip. The analytical predictions agree well with finite element analysis. This accurate model may serve as the theoretical basis for system optimization, especially for determining the optimal condition in the laser-driven noncontact microtransfer printing. [ABSTRACT FROM AUTHOR]

Solid-supported chemical libraries have proven useful for the rapid and cost-effective discovery of bioactive compounds. However, traditional on-bead screening involves time-intensive chemical characterization of hit compounds and high false positive rates. Herein, we report a new platform for encoded chemical synthesis and solid-supported screening using p-Chips, microsized silicon microtransponders capable of storing and emitting unique numerical identifiers (IDs). By encoding the structures of library members using p-Chip IDs, we can track compound identities throughout both split-and-pool synthesis and protein binding assays without destructive cleavage. Thanks to the numerical IDs, our p-Chip platform can provide binding constants for library members simply by stripping and reprobing with different protein concentrations, unlike traditional on-bead assays. To showcase these features, we synthesized a library of 108 hemagglutinin (HA) peptide variants using split-and-pool approach, and measured EC50s for each variant directly on p-Chips. On-chip EC50s obtained from these studies showed excellent correlation (80%) with those obtained using traditional ELISA methods. Our screen also yielded a false positive rate of 14%, markedly superior to that reported for conventional bead-based binding studies (66-96%).1-9 On the basis of these results, we believe the p-Chip platform has the potential to improve the effectiveness of solid-supported high-throughput screening by a significant margin. [ABSTRACT FROM AUTHOR]

• A highly sensitive, label-free electrochemical sensor was developed for the detection of the stx1 gene from STEC using silicon chips comprising interdigitated microelectrodes (IDEs). • A selective modification of sensor IDE with chitosan and probe DNA was confirmed using fluorescence. • Applying an open circuit potential to the accumulator IDE allowed a more efficient accumulation of methylene blue between double-strand DNA. • The specificity of the developed sensor was confirmed using DNA extracted from wild-type strains. Shiga toxin-producing E. coli (STEC) is a food-borne pathogen of great concern due to the severity of the disease it can cause. A key pathogenicity factor is the ability to produce Shiga T Toxin 1 and 2, which are encoded by genes stx. Herein we report the development of a highly sensitive, label-free, electrochemical DNA-based sensor for the detection of the stx1 gene using interdigitated gold microelectrodes (IDEs) on fully integrated silicon chips. Each IDE comprised a working IDE, used for DNA probe immobilisation and an accumulator IDE. The working IDE was modified with gold nanoparticles (Au NPs) and chitosan gold nanocomposite to allow a covalent attachment of amine-modified probe DNA. The electrochemical detection was undertaken using methylene blue (MB) as a redox molecule, which intercalated into the double-strand DNA. The accumulator IDE was used for the electrostatic accumulation of the MB to the DNA binding region of the sensor thereby greatly enhancing sensitivity. The reduction of MB was recorded using square wave voltammetry (SWV). Using this approach, we achieved a linear response between 10−16 and 10−6 M of synthetic target strand with the lowest measured limit of detection of 100 aM after 20 min of hybridisation time. Subsequently, chromosomal DNA from four different E. coli strains (two stx1 positives and two stx1 negatives), Listeria monocytogenes and Bacillus cereus were used to confirm the selectivity of the presented method. This novel on-chip biosensor for the detection of STEC has the potential to be used for point-of-use detection. [ABSTRACT FROM AUTHOR]

Silicon photonics is a promising solution for on-chip optical clock distribution. We developed an adhesive bonding process to integrate silicon nanomembranes onto silicon chips. The single-mode strip waveguide fabricated on this adhesively bonded silicon membrane has a propagation loss of 4.3 dB/cm. A grating-coupled 1-to-32 H-tree optical distribution is experimentally demonstrated. Each branch includes 1.1-cm long strip waveguides, five Y-splitters, and three 90° bends. This optical distribution has a insertion loss of 13.9 dB, uniformity of 0.72 dB, and 3-dB bandwidth of 880 GHz determined by optical autocorrelation. [ABSTRACT FROM PUBLISHER]

A solid state bonding technique was designed and developed to bond silicon (Si) chips to silver (Ag) buffer layer electroplated on copper (Cu) substrates at a temperature (260^\circC) far below the melting temperature of Ag (961^\circC). This is possible because Ag atoms in Ag buffer are brought in contact with the gold (Au) atoms in Au layer coated on Si chip. The close proximity in atomic scale allows the Ag and Au atoms to see each other, to share electrons and to bond to each other. The possibility of mating between Au and Ag surfaces relies on the deformation of Ag. Ag, with proper annealing, is ductile and has low yield strength. Its surface can thus deform to conform to and to follow the surface of Au layer coated on Si chip. Its ductile property can also help accommodate large mismatch in coefficient of thermal expansion between Si (2.7\times 10^-6~^\circC^-1) and Cu (17\times 10^-6~^\circC^-1). Ag also has the highest electrical and thermal conductivities among all metals. It is the dream bonding medium. The challenge is to bond Ag to other materials at a temperature compatible to electronic packaging processes, 260^\circC. In this research, Si chips are coated with thin chromium (Cr) and Au layers and then bonded to Ag buffer plated on Cu substrates. To make Ag buffer ductile, Ag buffer together with Cu substrate is annealed to increase its grain size by a factor of 25. The bonding was performed at 260^\circC with 1000 psi (6.89 MPa) static pressure. There is no molten phase involved in the bonding process. Scanning electron microscope evaluations show that on the revealed cross section no voids or gaps are observed on Si/Ag and Ag/Cu bonding interfaces. The bonded structure consists of only Si/Cr/Au/Ag/Cu and can sustain at high operating temperature due to high melting temperature of Ag. [ABSTRACT FROM PUBLISHER]

This study describes an extremely sensitive and simple assay to measure small volumes of solutions, <1 nL. The assay takes advantage of the Sandell-Kolthoff reaction in which yellow cerium(IV) is reduced to colorless cerium(III) in the presence of arsenic(III) and catalytic quantities of iodide ion. The reaction is linear with respect to the rate of Ce(IV) reduction and the quantity of I- present. Typical assays can measure 10-100 picomoles of iodide in a sample. When I- is substituted for chloride ion in standard biological buffers, such as Tris-buffered saline, the assay can be used to determine the volume of solution printed in a microarray. [ABSTRACT FROM AUTHOR]

Abstract: Planar patch-clamp is a two-dimensional variation of traditional patch-clamp. By contrast to classical glass micropipette, the seal quality of silicon patch-clamp chips (i.e. seal resistance and seal success rate) have remained poor due to the planar geometry and the nature of the substrate and thus partially obliterate the advantages related to planar patch-clamp. The characterization of physical parameters involved in seal formation is thus of major interest. In this paper, we demonstrate that the physical characterization of surfaces by a set of techniques (Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), surface energy (polar and dispersive contributions), drop angles, impedance spectroscopy, combined with a statistical design of experiments (DOE)) allowed us discriminating chips that provide relevant performances for planar patch-clamp analysis. Analyses of seal quality demonstrate that dispersive interactions and micropore size are the most crucial physical parameters of chip surfaces, by contrast to surface roughness and dielectric membrane thickness. This multi-scale study combined with electrophysiological validation of chips on a diverse set of cell-types expressing various ion channels (IRK1, hERG and hNav1.5 channels) unveiled a suitable patch-clamp chip candidate. This original approach may inspire novel strategies for selecting appropriate surface parameters dedicated to biochips. [ABSTRACT FROM AUTHOR]

This paper addresses a new flip chip interconnection technology, flexible flip chip connection (F2C2) technology, for attaching silicon chips to a chip carrier using flexible copper wires. F2C2 is a novel approach to create area array flip chip interconnections using a matrix block of wires encapsulated with a heat-resistant, dissolvable substance. A slice from the wire matrix ingot is first attached to the chip using solder. The other end of the slice is then matched and soldered to the footprint of a substrate. Finally, the encapsulating, dissolvable substance is removed from the body of the slice, leaving the chip attached to the carrier by the inter- disposed, flexible copper wires. The compliant copper wire interconnections can accommodate the coefficient of thermal expansion (CTE) mismatch problem between die and substrate, thus eliminating the need for underfill. [ABSTRACT FROM PUBLISHER]

Current advances in materials science have demonstrated that extracellular mechanical cues can define cell function and cell fate. However, a fundamental understanding of the manner in which intracellular mechanical cues affect cell mechanics remains elusive. How intracellular mechanical hindrance, reinforcement, and supports interfere with the cell cycle and promote cell death is described here. Reproducible devices with highly controlled size, shape, and with a broad range of stiffness are internalized in HeLa cells. Once inside, they induce characteristic cell-cycle deviations and promote cell death. Device shape and stiffness are the dominant determinants of mechanical impairment. Device structural support to the cell membrane and centering during mitosis maximize their effects, preventing spindle centering, and correct chromosome alignment. Nanodevices reveal that the spindle generates forces larger than 114 nN which overcomes intracellular confinement by relocating the device to a less damaging position. By using intracellular mechanical drugs, this work provides a foundation to defining the role of intracellular constraints on cell function and fate, with relevance to fundamental cell mechanics and nanomedicine., (© 2022 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

A novel suspended planar-array chips technology is described, which effectively allows molecular multiplexing using a single suspended chip to analyze extraordinarily small volumes. The suspended chips are fabricated by combining silicon-based technology and polymer-pen lithography, obtaining increased molecular pattern flexibility, and improving miniaturization and parallel production. The chip miniaturization is so dramatic that it permits the intracellular analysis of living cells., (© 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In the cosmetics industry, emulsions play a key-role in active solubilization and texture/efficacy optimization. However, depending on their physico-chemical properties, the active ingredients are often more stable in a single phase: for example, Vitamin A is more stable in an oily phase than in a water phase. We have developed a special mixing device which produces an emulsion in the body of the pump, immediately before application on the skin. The mixing unit consists of two silicon chips. Each chip has several Y-shaped microchannels and intersections etched on its upper surface. When the two etched surfaces are bonded together, they produce series of interconnecting micromixing elements which permit the repeat mixing of the two phases, thus producing an extremely homogenous emulsion. These micromixers require carefully designed formulae in which the physico-chemical properties of each raw material are essential to obtain a spontaneous emulsion. This device has been incorporated into a spray pack and optimized to deliver the spontaneous emulsion when finger pressure is applied. [ABSTRACT FROM AUTHOR]