Patterning Process Research Articles

Self-isolating electrode deposition process using the area-selective MoO2 and MoO3 atomic layer deposition technique

The traditional patterning process for semiconductor devices typically involves multiple steps, including thin film deposition across the entire substrate, selective removal of unwanted regions through lithography and etching, and subsequent isolation. While area-selective deposition process has been employed to eliminate the need for lithography and etching, the isolation step remains essential. In this study, we suggest an innovative approach to achieve “self-isolation electrode formation” using MoO2 and MoO3 as electrode and inter-metallic insulator materials. In a single deposition batch and subsequent post-deposition annealing (PDA) process, deposited MoOx (x: 2∼3) thin films exhibited transformation into highly crystalline MoO2 and MoO3 with low crystallinity, depending on whether they were deposited on TiN or SiO2 surfaces. We conducted comprehensive analyses, including chemical and electrical characterizations, as well as first-principles calculations based on density-functional theory, to elucidate the underlying mechanisms responsible for the differential reduction and crystallization of MoOx thin films. Finally, we successfully demonstrated the formation of self-isolation electrodes within a vertical structure, accomplished through a single-step process involving MoOx deposition and subsequent PDA. This novel approach, built upon advanced area-selective deposition techniques, holds great promise for the development of state-of-the-art semiconductor devices.

Highly reliable and stretchable OLEDs based on facile patterning method: toward stretchable organic optoelectronic devices

Stretchable displays attract significant attention because of their potential applications in wearable electronics, smart textiles, and human-conformable devices. This paper introduces an electrically stable, mechanically ultra-robust, and water-resistant stretchable OLED display (SOLED) mounted on a stress-relief pillar platform. The SOLED is fabricated on a thin, transparent polyethylene terephthalate (PET) film using conventional vacuum evaporation, organic-inorganic hybrid thin film encapsulation (TFE), and a nonselective laser patterning process. This simple and efficient process yields an OLED display with exceptional stretchability, reaching up to 95% strain and outstanding durability, enduring 100,000 stretch-release cycles at 50% strain. Operational lifetime and water-resistant storage lifetime measurements confirm that the TFE provides effective protection even after the nonselective laser patterning process. A 3 × 3 array SOLED display module mounted on a stress-relief pillar platform is successfully implemented, marking the first case of water-resistant display array operation in the field of SOLEDs. This work aims to develop practical stretchable displays by offering a reliable fabrication method and device design for creating mechanically robust and adaptable displays, potentially paving the way for future advances in human-conformable electronics and other innovative applications.

Area-selective atomic layer deposition on 2D monolayer lateral superlattices

The advanced patterning process is the basis of integration technology to realize the development of next-generation high-speed, low-power consumption devices. Recently, area-selective atomic layer deposition (AS-ALD), which allows the direct deposition of target materials on the desired area using a deposition barrier, has emerged as an alternative patterning process. However, the AS-ALD process remains challenging to use for the improvement of patterning resolution and selectivity. In this study, we report a superlattice-based AS-ALD (SAS-ALD) process using a two-dimensional (2D) MoS2-MoSe2 lateral superlattice as a pre-defining template. We achieved a minimum half pitch size of a sub-10 nm scale for the resulting AS-ALD on the 2D superlattice template by controlling the duration time of chemical vapor deposition (CVD) precursors. SAS-ALD introduces a mechanism that enables selectivity through the adsorption and diffusion processes of ALD precursors, distinctly different from conventional AS-ALD method. This technique facilitates selective deposition even on small pattern sizes and is compatible with the use of highly reactive precursors like trimethyl aluminum. Moreover, it allows for the selective deposition of a variety of materials, including Al2O3, HfO2, Ru, Te, and Sb2Se3.

Mapping dynamic spatial patterns of brain function with spatial-wise attention

Objective: Using functional magnetic resonance imaging (fMRI) and deep learning to discover the spatial pattern of brain function, or functional brain networks (FBNs) has been attracted many reseachers. Most existing works focus on static FBNs or dynamic functional connectivity among fixed spatial network nodes, but ignore the potential dynamic/time-varying characteristics of the spatial networks themselves. And most of works based on the assumption of linearity and independence, that oversimplify the relationship between blood-oxygen level dependence signal changes and the heterogeneity of neuronal activity within voxels. Approach: To overcome these problems, we proposed a novel spatial-wise attention (SA) based method called Spatial and Channel-wise Attention Autoencoder (SCAAE) to discover the dynamic FBNs without the assumptions of linearity or independence. The core idea of SCAAE is to apply the SA to generate FBNs directly, relying solely on the spatial information present in fMRI volumes. Specifically, we trained the SCAAE in a self-supervised manner, using the autoencoder to guide the SA to focus on the activation regions. Experimental results show that the SA can generate multiple meaningful FBNs at each fMRI time point, which spatial similarity are close to the FBNs derived by known classical methods, such as independent component analysis. Main results: To validate the generalization of the method, we evaluate the approach on HCP-rest, HCP-task and ADHD-200 dataset. The results demonstrate that SA mechanism can be used to discover time-varying FBNs, and the identified dynamic FBNs over time clearly show the process of time-varying spatial patterns fading in and out. Significance: Thus we provide a novel method to understand human brain better. Code is available at https://github.com/WhatAboutMyStar/SCAAE.

Improvement of electrical characteristics and wet etching procedures for InGaTiO electrodes in organic light-emitting diodes through hydrogen doping

We investigated the effect of hydrogen doping on characteristics of InGaTiO (IGTO) electrode with high conductivity and transmittance during sputtering process. After hydrogen doping, the 300 nm-thick IGTO:H electrode showed lower sheet resistance of 13.79 Ω/square compared to sheet resistance (69.2 Ω/square) of pure IGTO electrode without change of optical transmittance. In addition, wet etching reaction rate of IGTO:H electrode for patterning process was significantly accelerated after hydrogen doping. Possible explanation for hydrogen doping effect on electrical properties and wet etching process of the IGTO:H electrode was suggested. The doped hydrogen influenced the electrical characteristics through the passivation of dangling bonds and oxygen vacancies. Moreover, it significantly impacts crystalline structure, consequently altering the etching rate. Using patterned IGTO:H electrodes, we fabricated red organic light emitting diodes (OLEDs) to show feasibility of the IGTO:H electrodes. External quantum efficiency and current efficiency of the red OLED with IGTO:H (10%) were higher than IGTO electrode without hydrogen doping, indicating that hydrogen doping is an effective method to improve the film properties and IGTO:H electrode can serve as a prospective transparent anode for both flexible and rigid OLEDs.

Neurophysiological correlates of the perceptual magnet effect in speech perception

This study investigated the Perceptual Magnet Effect (PME) in speech perception using behavioral and Event-Related Potentials (ERP) measures. There were two primary research questions: (1) whether category goodness rating influences speech discrimination with reduced sensitivity near the prototype and increased sensitivity in the vicinity of a poor exemplar, (2) whether the PME is domain-specific to speech sounds. Twenty adult native English speakers participated in identification, goodness rating, and discrimination tasks. The stimuli were synthesized vowels for /a/ and their nonspeech analogs by systematically varying the first two formants. ERP oddball conditions included four conditions presented in a counter-balanced order with the prototypical /a/ as the standard stimuli and its variants as deviants, and a non-prototypical /a/ as the standard and its variants as deviants, as well as the nonspeech matches. Results indicated that participants rated vowel category goodness based on the F2/F1 ratio for the /a/ sounds. Mismatch negativity amplitudes in the two speech conditions aligned with PME predictions, but similar patterns were also observed in the nonspeech conditions. The findings collectively demonstrated neurophysiological evidence for the perceptual organization of within-category variations in line with PME, which may transfer to auditory processing of similar acoustic patterns in nonspeech.

Pattern-dependent resistivity variations in inkjet-printed conductors due to non-uniform ink drying

When fabricating inkjet-printed electronic devices and circuits, inkjet-printed conductive materials require drying and sintering to improve electrical conductivity. Electrical conductivity should be the same irrespective of pattern design, size, location, or density of adjacent patterns. However, we demonstrate that spatial variations in the drying process for inkjet-printed patterns with proximity to others cause resistivity variations. These resistivity variations are studied here experimentally for different circuit patterns and in arrays of inkjet-printed square electrodes. This variation depends not only on the location of each electrode in an array but also on the number of electrodes. This means that for the same drying temperature and duration, the array with a larger number of electrodes exhibits a larger resistivity variation. The sooner an electrode dries, the lower resistivity it achieves. The resistivity variation between an individual electrode and the center electrode in a 7 × 7 electrode array can be a factor of seven. This variation decreases for lower numbers of electrodes to a factor of three for a 3 × 3 array. Furthermore, x-ray photoelectron spectroscopy analyses provide evidence for the residual presence of carbon-based materials within electrodes after the drying process. These results confirm that the location of electrodes within an array significantly influences the amount of residual carbon-based materials, thereby contributing to resistivity variations. Although intense pulsed light sintering can decrease this variation, its optimal parameters depend on the printed designs, and our simulation results show a non-uniform temperature profile over the electrode arrays. Temperature increases more at the center of patterns than the corners, which can be useful in this case to improve resistivity uniformity. In this study, for the first time, we show how different printed shapes and designs can result in non-uniform resistivity after drying and sintering.

Plant compartment niche is more important in structuring the fungal community associated with alpine herbs in the subnival belt of the Qiangyong glacier than plant species

The plant compartment niche (i.e., the host plant provides various microhabitats for the microbial community, such as the rhizosphere, root endosphere, leaf endosphere, and phylloplane) and plant species play a significant role in shaping the plant-associated microbial community assembly. However, in the mycobiome associated with alpine herbs in the subnival belt research, little work has been done to assess the contribution of plant compartment niches and plant species to fungal community variation and to reveal the plant compartment niche differentiation of fungal communities. In this study, we quantified the fungal communities associated with the rhizosphere soil, root endospheres, and leaf endospheres of three alpine herbs (Rheum spiciforme, Eriophyton wallichii, and Rhodiola bupleuroides) in the subnival belt of the Qiangyong glacier using high-throughput DNA sequencing. Our results revealed that the variation in diversity and composition of the fungal community was predominantly shaped by plant compartment niche rather than plant species. Rhizosphere soil exhibited the highest level of fungal diversity and niche breadth, while the lowest level was observed in the leaf endosphere. The fungal community composition significantly differed across different plant compartment niches. Fungal co-occurrence networks of the root endosphere and leaf endosphere were more complex and showed higher centrality and connectedness than the rhizosphere soil. Moreover, we also found that the deterministic process governed the fungal community assembly, and the host plant exerts stronger selection pressure on the leaf endophytes in comparison with the root endophytes. The root endophytes are the primary potential contributors to the leaf endophytes, compared with the fungal community associated with rhizosphere soil. Further, the Pleosporaceae, Davidiellaceae, and Chaetomiaceae were significantly enriched and overlapped in two plant compartment niches (root endosphere and leaf endosphere). Collectively, this study reveals that the variation in the diversity and composition of fungal communities associated with three alpine herbs were primarily affected by plant compartment niches rather than plant species. Additionally, this study also reveals that the diversity, composition, co-occurrence pattern, and assembly process of fungal communities associated with three alpine herbs exhibited plant compartment niche differentiation. These results provide a novel insight into the community assembly and ecological interactions of fungal communities associated with plants in harsh environments.

Multiple Exhumation Stages During the Cenozoic Evolution of the Northeast Tibetan Plateau

AbstractThe Cenozoic growth history of the northeast (NE) Tibetan Plateau has been strongly debated in the past few years with three deformation models being proposed: progressive northeastward propagation, out‐of‐sequence deformation, and episodic deformation. Reconstruction of the long‐term deformation and exhumation history of the different blocks can help elucidate the growth pattern and tectonic processes involved in the formation of the Plateau. Both the Qaidam and Jiuquan basins—the two largest basins of the NE Tibetan Plateau—contain continuous and well‐exposed successions of synorogenic sediments that span the entire Cenozoic. We used apatite fission‐track thermochronology, sedimentary facies, and structural and provenance analyses of these successions to determine the exhumation history of the Tibetan Plateau. Five distinct fast exhumation events were recognized and dated: 65–54, 43–39, 34–29, 24–21, and 16–15 Ma. Comparison with existing morphotectonic information enabled us to reconstruct a multiple‐stage growth scenario for the NE Tibetan Plateau in the context of the surface uplift phases across the Himalayan‐Tibetan orogen during the Cenozoic. Overall, our findings support the episodic deformation model and emphasizes that the current relief of the NE Tibetan Plateau is largely derived from these five of stage of exhumation.

Ultrafast Solid-State Electrochemical Imprinting Utilizing Polymer Electrolyte Membrane Stamps for Static/Dynamic Structural Coloration and Letter Encryption.

Micro and nanopatterned surfaces hold potential for various applications, such as wettability control, antibiofouling, and optical components. However, conventional patterning processes are characterized by complexity, high costs, and environmental burdens because of the use of resists. Therefore, this paper proposes facile and ultrafast electrochemical imprinting employing a polymer electrolyte membrane (PEM) stamp for achieving micro and nanoscale patterning on Si surfaces. The solid-state electrochemical process efficiently generates oxide and hydrated oxide (Si-OH) patterns within several seconds at room temperature in a dry ambient environment. The formed oxide pattern can be employed as an etching mask to prepare diffraction gratings with diverse high-resolution (≈100nm) patterns utilizing the dry PEM stamp. The resulting oxide pattern on the Si surface exhibits instantaneous structural coloration upon exposure to humid air, attributable to the formation of a water microdroplet array on the oxide pattern. The oxide pattern is successfully applied for dynamic diffraction grating and letter encryption. The proposed solid-state electrochemical oxidation scheme based on a PEM stamp, which eliminates the need for liquid electrolyte and resist, represents a simple and ultrafast process with a time cost of a few seconds, characterized by low processing costs and environmental impact.

Spontaneous Alignment of Myotubes Through Myogenic Progenitor Cell Migration.

In large-volume muscle injuries, widespread damage to muscle fibers and the surrounding connective tissue prevents myogenic progenitor cells (MPCs) from initiating repair. There is a clinical need to rapidly fabricate large muscle tissue constructs for integration at the site of large volume muscle injuries. Most strategies for myotube alignment require microfabricated structures or prolonged orientation times. We utilize the MPC's natural propensity to close gaps across an injury site to guide alignment on collagen I. When MPCs are exposed to an open boundary free of cells, they migrate unidirectionally into the cell-free region and align perpendicular to the original boundary direction. We study the utility of this phenomenon with biotin-streptavidin adhesion to position the cells on the substrate, and then demonstrate the robustness of this strategy with unmodified cells, creating a promising tool for MPC patterning without interrupting their natural function. We preposition MPCs in straight-line patterns separated with small gaps. This temporary positioning initiates the migratory nature of the MPCs to align and form myotubes across the gaps, similar to how they migrate and align with a single open boundary. There is a directional component to the MPC migration perpendicular (90°) to the original biotin-streptavidin surface patterns. The expression of myosin heavy chain, the motor protein of muscle thick filaments, is confirmed through immunocytochemistry in myotubes generated from MPCs in our patterning process, acting as a marker of skeletal muscle differentiation. The rapid and highly specific binding of biotin-streptavidin allows for quick formation of temporary patterns, with MPC alignment based on natural regenerative behavior rather than complex fabrication techniques.

Sall genes regulate hindlimb initiation in mouse embryos.

Vertebrate limbs start to develop as paired protrusions from the lateral plate mesoderm at specific locations of the body with forelimb buds developing anteriorly and hindlimb buds posteriorly. During the initiation process, limb progenitor cells maintain active proliferation to form protrusions and start to express Fgf10, which triggers molecular processes for outgrowth and patterning. Although both processes occur in both types of limbs, forelimbs (Tbx5), and hindlimbs (Isl1) utilize distinct transcriptional systems to trigger their development. Here, we report that Sall1 and Sall4, zinc finger transcription factor genes, regulate hindlimb initiation in mouse embryos. Compared to the 100% frequency loss of hindlimb buds in TCre; Isl1 conditional knockouts, Hoxb6Cre; Isl1 conditional knockout causes a hypomorphic phenotype with only approximately 5% of mutants lacking the hindlimb. Our previous study of SALL4 ChIP-seq showed SALL4 enrichment in an Isl1 enhancer, suggesting that SALL4 acts upstream of Isl1. Removing 1 allele of Sall4 from the hypomorphic Hoxb6Cre; Isl1 mutant background caused loss of hindlimbs, but removing both alleles caused an even higher frequency of loss of hindlimbs, suggesting a genetic interaction between Sall4 and Isl1. Furthermore, TCre-mediated conditional double knockouts of Sall1 and Sall4 displayed a loss of expression of hindlimb progenitor markers (Isl1, Pitx1, Tbx4) and failed to develop hindlimbs, demonstrating functional redundancy between Sall1 and Sall4. Our data provides genetic evidence that Sall1 and Sall4 act as master regulators of hindlimb initiation.

Spatial-temporal order-disorder transition in angiogenic NOTCH signaling controls cell fate specification.

Angiogenesis is a morphogenic process resulting in the formation of new blood vessels from pre-existing ones, usually in hypoxic micro-environments. The initial steps of angiogenesis depend on robust differentiation of oligopotent endothelial cells into the Tip and Stalk phenotypic cell fates, controlled by NOTCH-dependent cell-cell communication. The dynamics of spatial patterning of this cell fate specification are only partially understood. Here, by combining a controlled experimental angiogenesis model with mathematical and computational analyses, we find that the regular spatial Tip-Stalk cell patterning can undergo an order-disorder transition at a relatively high input level of a pro-angiogenic factor VEGF. The resulting differentiation is robust but temporally unstable for most cells, with only a subset of presumptive Tip cells leading sprout extensions. We further find that sprouts form in a manner maximizing their mutual distance, consistent with a Turing-like model that may depend on local enrichment and depletion of fibronectin. Together, our data suggest that NOTCH signaling mediates a robust way of cell differentiation enabling but not instructing subsequent steps in angiogenic morphogenesis, which may require additional cues and self-organization mechanisms. This analysis can assist in further understanding of cell plasticity underlying angiogenesis and other complex morphogenic processes.

Estimation Method of Remaining Life and Hot Spot Temperature According to Real-Time Transformer Load Pattern Process

Estimation Method of Remaining Life and Hot Spot Temperature According to Real-Time Transformer Load Pattern Process

Sub-volt high-speed silicon MOSCAP microring modulator driven by high-mobility conductive oxide

Silicon microring modulator plays a critical role in energy-efficient optical interconnect and optical computing owing to its ultra-compact footprint and capability for on-chip wavelength-division multiplexing. However, existing silicon microring modulators usually require more than 2 V of driving voltage (Vpp), which is limited by both material properties and device structures. Here, we present a metal-oxide-semiconductor capacitor microring modulator through heterogeneous integration between silicon photonics and titanium-doped indium oxide, which is a high-mobility transparent conductive oxide (TCO) with a strong plasma dispersion effect. The device is co-fabricated by Intel’s photonics fab and our in-house TCO patterning processes, which exhibits a high modulation efficiency of 117 pm/V and consequently can be driven by a very low Vpp of 0.8 V. At a 11 GHz modulation bandwidth where the modulator is limited by the RC bandwidth, we obtained 25 Gb/s clear eye diagrams with energy efficiency of 53 fJ/bit.

Automatic center identification of electron diffraction with multi-scale transformer networks

Selected area electron diffraction (SAED) is a widely used technique for characterizing the structure and measuring lattice parameters of materials. An autonomous analytic method has become an urgent demand for the large-scale SAED data produced from in-situ experiments. In this work, we realize the automatic processing for center identification with a proposed deep segmentation model named the multi-scale Transformer (MS-Trans) network. This algorithm enables robust segmentation of the central spots by combining a novel gated axial-attention module and multi-scale feature fusion. The proposed MS-Trans model shows high precision and robustness, enabling autonomous processing of SAED patterns without any prior knowledge. The application on in-situ SAED data of the oxidation process of FeNi alloy demonstrates its capability of implementing autonomous quantitative processing.© 2017 Elsevier Inc. All rights reserved.

Praseodymium-Doped Ge20In5Sb10Se65 Films Based on Argon Plasma Cosputtering for Infrared-Luminescent Integrated Photonic Circuits.

In this paper, we report on the infrared luminescence of amorphous praseodymium-doped Ge20In5Sb10Se65 waveguides, which can be used as infrared sources in photonic integrated circuits on silicon substrates. Amorphous chalcogenide thin films were deposited by radiofrequency magnetron cosputtering using an argon plasma whose deposition parameters were optimized for chalcogenide materials. The micropatterning as ridge waveguides of the chalcogenide cosputtered films was performed using photolithography and plasma-coupled reactive ion etching techniques. The influence of the rare earth concentration within those thin films on their optical properties and rare earth spectroscopic properties was investigated. Using an excitation wavelength of 1.55 μm, the mid-infrared luminescence of Pr3+ ions from 2.5 to 5.5 μm was clearly demonstrated for studied chalcogenide materials. A wide range of waveguide widths and doping ratios were tested, assessing the ability of the cosputtering technique to preserve the luminescence properties of the rare earth ions initially observed in the bulk glass through the thin-film deposition and patterning process.

How the intrinsic functional connectivity patterns of the semantic network support semantic processing.

Semantic processing, a core of language comprehension, involves the activation of brain regions dispersed extensively across the frontal, temporal, and parietal cortices that compose the semantic network. To comprehend the functional structure of this semantic network and how it prepares for semantic processing, we investigated its intrinsic functional connectivity (FC) and the relation between this pattern and semantic processing ability in a large sample from the Human Connectome Project (HCP) dataset. We first defined a well-studied brain network for semantic processing, and then we characterized the within-network connectivity (WNC) and the between-network connectivity (BNC) within this network using a voxel-based global brain connectivity (GBC) method based on resting-state functional magnetic resonance imaging (fMRI). The results showed that 97.73% of the voxels in the semantic network displayed considerably greater WNC than BNC, demonstrating that the semantic network is a fairly encapsulated network. Moreover, multiple connector hubs in the semantic network were identified after applying the criterion of WNC > 1 SD above the mean WNC of the semantic network. More importantly, three of these connector hubs (i.e., the left anterior temporal lobe, angular gyrus, and orbital part of the inferior frontal gyrus) were reliably associated with semantic processing ability. Our findings suggest that the three identified regions use WNC as the central mechanism for supporting semantic processing and that task-independent spontaneous connectivity in the semantic network is essential for semantic processing.

Deep Learning in the Phase Extraction of Electronic Speckle Pattern Interferometry

Electronic speckle pattern interferometry (ESPI) is widely used in fields such as materials science, biomedical research, surface morphology analysis, and optical component inspection because of its high measurement accuracy, broad frequency range, and ease of measurement. Phase extraction is a critical stage in ESPI. However, conventional phase extraction methods exhibit problems such as low accuracy, slow processing speed, and poor generalization. With the continuous development of deep learning in image processing, the application of deep learning in phase extraction from electronic speckle interferometry images has become a critical topic of research. This paper reviews the principles and characteristics of ESPI and comprehensively analyzes the phase extraction processes for fringe patterns and wrapped phase maps. The application, advantages, and limitations of deep learning techniques in filtering, fringe skeleton line extraction, and phase unwrapping algorithms are discussed based on the representation of measurement results. Finally, this paper provides a perspective on future trends, such as the construction of physical models for electronic speckle interferometry, improvement and optimization of deep learning models, and quantitative evaluation of phase extraction quality, in this field.

Engineered cocultures of iPSC-derived atrial cardiomyocytes and atrial fibroblasts for modeling atrial fibrillation.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia treatable with antiarrhythmic drugs; however, patient responses remain highly variable. Human induced pluripotent stem cell-derived atrial cardiomyocytes (iPSC-aCMs) are useful for discovering precision therapeutics, but current platforms yield phenotypically immature cells and are not easily scalable for high-throughput screening. Here, primary adult atrial, but not ventricular, fibroblasts induced greater functional iPSC-aCM maturation, partly through connexin-40 and ephrin-B1 signaling. We developed a protein patterning process within multiwell plates to engineer patterned iPSC-aCM and atrial fibroblast coculture (PC) that significantly enhanced iPSC-aCM structural, electrical, contractile, and metabolic maturation for 6+ weeks compared to conventional mono-/coculture. PC displayed greater sensitivity for detecting drug efficacy than monoculture and enabled the modeling and pharmacological or gene editing treatment of an AF-like electrophysiological phenotype due to a mutated sodium channel. Overall, PC is useful for elucidating cell signaling in the atria, drug screening, and modeling AF.