Fabrication Methodology Research Articles

A design TCADAS tool for semiconductor devices and case study of 65 nm conventional floating-gate MOS transistor

An automatic programming tool has become an essential component in virtual fabrication in recent years. This paper aims to propose a methodology of virtual fabrication for semiconductor devices and design a tool called Technology Computer-Aided Design Automatic Simulation (TCADAS) which can perform a completely virtual fabrication, device simulation, process variation, and output extraction. Especially, the TCADAS tool eliminates drudgery when studying semiconductor devices such as complexity in setting inputs, substantial manual work, and long run time of simulations. This work investigates the completed flow for a 65 nm conventional Floating-gate MOS transistor as a case study, which is widely considered a vital determinant of the non-volatile memory field. A detailed automatic process from the entry to a completed three-dimension structure, device characterization, extract important output parameters such as memory window, ION/IOFF, Gate Coupling Ratio (GCR), and speed operations are presented. The TCADAS tool was designed by Python language and the utilities of TCAD Silvaco tools including Athena, Atlas, and DevEdit3D.

The Technical and Industrial Challenges Faced by Fuel Cells—A Case Study of PEMFC And SOFC

Fuel cells are a proficient and environmental technology that directly transmutes chemical energy into electrical energy. Within this domain, Proton Exchange Membrane Fuel Cells (PEMFCs) and Solid Oxide Fuel Cells (SOFCs) are at the forefront of small-scale applications and industrial power generation, respectively. The efficacy and economic feasibility of PEMFCs are contingent upon key components, such as the proton exchange membrane and mass transport layers. Consequently, contemporary research is geared towards the optimization of these components to augment performance while concurrently mitigating costs. Conversely, the operational capacity of SOFCs at elevated temperatures has spurred research efforts aimed at material enhancement and the diversification of applications. These advancements encompass the integration of additives, the exploration of novel membrane fabrication methodologies, and the development of innovative structural designs for fuel cells. Although there have been progressive strides in the realm of hydrogen-powered vehicles and fuel cell power plants, their assimilation into the market has been somewhat languid, with commercialization still facing a myriad of challenges. Notwithstanding these hurdles, it is anticipated that with the ongoing evolution of technology and a concomitant reduction in costs, fuel cells will persist as a pivotal component in the quest for energy cleanliness and efficiency.

A Virtual Fabrication and High-Performance Design of 65 nm Nanocrystal Floating-Gate Transistor

Floating-gate transistor lies at the heart of many aspects of semiconductor applications such as neural networks, analog mixed-signal, neuromorphic computing, and especially in nonvolatile memories. The purpose of this paper was to design a high-performance nanocrystal floating-gate transistor in terms of a large memory window, low power, and extraordinary erasing speeds. Besides, the transistor achieves a thin thickness of the tunnel gate oxide layer. In order to obtain the high-performance design, this work proposed a set of structure parameters for the device such as the tunnel oxide layer thickness, Interpoly Dielectric (IPD), dot dimension, and dot spacing. Besides, this work was successful in the virtual fabrication process and methodology to fabricate and characterize the 65 nm nanocrystal floating-gate transistor. Regarding the results, while the fabrication process solves the limitation of the tunnel oxide layer thickness with the small value of 6 nm, the performance of the transistor has been significantly improved, such as 2.8 V of the memory window with the supply voltage of ±6 V at the control gate. In addition, the operation speeds are compatible, especially the rapid erasing speeds of 2.03 μs, 28.6 ns, and 1.6 ns when the low control gate voltages are ±9 V, ±12 V, and ±15 V, respectively.

Gel-mediated recruitment of conventional type 1 dendritic cells potentiates the therapeutic effects of radiotherapy

The efficacy of radiotherapy has not yet achieved optimal results, partially due to insufficient priming and infiltration of effector immune cells within the tumor microenvironment (TME), which often exhibits suppressive phenotypes. In particular, the infiltration of X–C motif chemokine receptor 1 (XCR1)-expressing conventional type-1 dendritic cells (cDC1s), which are critical in priming CD8+ cytotoxic T cells, within the TME is noticeably restricted. Hence, we present a facile methodology for the efficient fabrication of a calcium phosphate hydrogel loaded with X–C motif chemokine ligand 1 (XCL1) to selectively recruit cDC1s. Manganese phosphate microparticles were also loaded into this hydrogel to reprogram the TME via cGAS-STING activation, thereby facilitating the priming of cDC1s propelled specific CD8+ T cells. They also polarize tumor-associated macrophages towards the M1 phenotype and reduce the proportion of regulatory cells, effectively reversing the immunosuppressive TME into an immune-active one. The yielded XCL1@CaMnP gel exhibits significant efficacy in enhancing the therapeutic outcomes of radiotherapy, particularly when concurrently administered with postoperative radiotherapy, resulting in an impressive 60 % complete response rate. Such XCL1@CaMnP gel, which recruits cDC1s to present tumor antigens generated in situ, holds great potential as a versatile platform for enhanced cancer treatment through modulating the immunosuppressive TME.

Progress in preparation, processing, and application of high dielectric polypropylene matrix composite materials

AbstractCurrently, in the era of highly advanced information technology, dielectric materials exhibit extensive potential applications in the realms of energy storage and information transmission. Polypropylene stands as one of the most prevalent plastics, lauded for its exceptional mechanical, thermal, electrical, and processing attributes. This article expounds upon the intricate essence and energy storage principles underpinning dielectric materials while pinpointing the areas in which the current dielectric materials necessitate enhancements. It further delves into the study's selection of polypropylene as the base material, with a focus on the impact of individual fillers (ferroelectric ceramics, carbon materials, etc.) and mixed filler nanoparticles on augmenting the dielectric properties of polypropylene. We also delve into pertinent fabrication techniques and methodologies, such as the solution blending method, melt blending method, and in situ polymerization method. In the context of existing polypropylene‐based composite dielectric materials, this article introduces two quintessential applications: insulation materials for direct current cables and metal capacitor films. Finally, it concludes by summarizing the obstacles and challenges that high‐performance polypropylene‐based dielectric composites confront and offers insights into potential avenues for future research.

Electrochemical sensors for analyte in saliva: recent update

Purpose This review provides an overview of recent advances in electrochemical sensors for analyte detection in saliva, highlighting their potential applications in diagnostics and health care. The purpose of this paper is to summarize the current state of the field, identify challenges and limitations and discuss future prospects for the development of saliva-based electrochemical sensors. Design/methodology/approach The paper reviews relevant literature and research articles to examine the latest developments in electrochemical sensing technologies for saliva analysis. It explores the use of various electrode materials, including carbon nanomaterial, metal nanoparticles and conducting polymers, as well as the integration of microfluidics, lab-on-a-chip (LOC) devices and wearable/implantable technologies. The design and fabrication methodologies used in these sensors are discussed, along with sample preparation techniques and biorecognition elements for enhancing sensor performance. Findings Electrochemical sensors for salivary analyte detection have demonstrated excellent potential for noninvasive, rapid and cost-effective diagnostics. Recent advancements have resulted in improved sensor selectivity, stability, sensitivity and compatibility with complex saliva samples. Integration with microfluidics and LOC technologies has shown promise in enhancing sensor efficiency and accuracy. In addition, wearable and implantable sensors enable continuous, real-time monitoring of salivary analytes, opening new avenues for personalized health care and disease management. Originality/value This review presents an up-to-date overview of electrochemical sensors for analyte detection in saliva, offering insights into their design, fabrication and performance. It highlights the originality and value of integrating electrochemical sensing with microfluidics, wearable/implantable technologies and point-of-care testing platforms. The review also identifies challenges and limitations, such as interference from other saliva components and the need for improved stability and reproducibility. Future prospects include the development of novel microfluidic devices, advanced materials and user-friendly diagnostic devices to unlock the full potential of saliva-based electrochemical sensing in clinical practice.

Biomimetic Curved Artificial Compound Eyes: A Review

Natural compound eyes (NCEs) are the most abundant and successful eye designs in the animal kingdom. An NCE consists of a number of ommatidia, which are distributed along a curved surface to receive light. This curved feature is critical to the functions of NCE, and it ensures that different ommatidia point to slightly different directions and thus enables panoramic vision, depth perception, and efficient motion tracking while minimizing aberration. Consequently, biomimetic curved artificial compound eyes (BCACEs) have garnered substantial research attention in replicating the anatomical configuration of their natural counterparts by distributing ommatidia across a curved surface. The reported BCACEs could be briefly categorized into 2 groups: fixed focal lengths and tunable focal lengths. The former could be further subcategorized into simplified BCACEs, BCACEs with photodetector arrays within curved surfaces, and BCACEs with light guides. The latter encompasses other tuning techniques such as fluidic pressure modulation, thermal effects, and pH adjustments. This work starts with a simple classification of NCEs and then provides a comprehensive review of main parameters, operational mechanisms, recent advancements, fabrication methodologies, and potential applications of BCACEs. Finally, discussions are provided on future research and development. Compared with other available review articles on artificial compound eyes, our work is distinctive since we focus especially on the “curved” ones, which are difficult to fabricate but closely resemble the architecture and functions of NCEs, and could potentially revolutionize the imaging systems in surveillance, machine vision, and unmanned vehicles.

Electrically driven hydrogel actuators: working principle, material design and applications

This review presents a comprehensive perspective on electrically driven hydrogel actuators, delving into their principles, molecular and composite designs, fabrication methodologies, device configurations, and their applications.

Silver nanoparticle doped laser-induced graphene fabrication methodology affects silver nanoparticle size, distribution, biological and electrochemical properties

Three fabrication methods for metal-doped laser-induced graphene (LIG) are compared resulting in stable nanoparticles embedded within LIG. Variable nanoparticle size, distribution, antibacterial and electrochemical properties were observed.

Salivary Gland Bioengineering.

Salivary gland dysfunction affects millions globally, and tissue engineering may provide a promising therapeutic avenue. This review delves into the current state of salivary gland tissue engineering research, starting with a study of normal salivary gland development and function. It discusses the impact of fibrosis and cellular senescence on salivary gland pathologies. A diverse range of cells suitable for tissue engineering including cell lines, primary salivary gland cells, and stem cells are examined. Moreover, the paper explores various supportive biomaterials and scaffold fabrication methodologies that enhance salivary gland cell survival, differentiation, and engraftment. Innovative engineering strategies for the improvement of vascularization, innervation, and engraftment of engineered salivary gland tissue, including bioprinting, microfluidic hydrogels, mesh electronics, and nanoparticles, are also evaluated. This review underscores the promising potential of this research field for the treatment of salivary gland dysfunction and suggests directions for future exploration.

Biomedical Applications of Titanium Alloys: A Comprehensive Review.

Titanium alloys have emerged as the most successful metallic material to ever be applied in the field of biomedical engineering. This comprehensive review covers the history of titanium in medicine, the properties of titanium and its alloys, the production technologies used to produce biomedical implants, and the most common uses for titanium and its alloys, ranging from orthopedic implants to dental prosthetics and cardiovascular devices. At the core of this success lies the combination of machinability, mechanical strength, biocompatibility, and corrosion resistance. This unique combination of useful traits has positioned titanium alloys as an indispensable material for biomedical engineering applications, enabling safer, more durable, and more efficient treatments for patients affected by various kinds of pathologies. This review takes an in-depth journey into the inherent properties that define titanium alloys and which of them are advantageous for biomedical use. It explores their production techniques and the fabrication methodologies that are utilized to machine them into their final shape. The biomedical applications of titanium alloys are then categorized and described in detail, focusing on which specific advantages titanium alloys are present when compared to other materials. This review not only captures the current state of the art, but also explores the future possibilities and limitations of titanium alloys applied in the biomedical field.

Investigation on microstructure characteristics and mechanical properties of twin wire-directed energy deposition-arc fabricated TiAl alloy regulated by the line energy

The microstructure of TiAl alloy is extremely sensitive to the thermal history. During additive manufacturing, multiple thermal cycles and partial remelting of the TiAl deposition layers take place. Therefore, the heat input would exert significant influences on microstructural and mechanical characteristics of additively manufactured TiAl alloys. In this study, TiAl alloys were prepared successfully by twin-wire directed energy deposition-arc (TW-DED-arc). Systematic studies were conducted to regulate the microstructure characteristic and the mechanical property of the as-deposited TiAl alloys via the line energy. The results indicate strong effects of the line energy on the microstructure and performance of the TiAl alloys, which show alternative distribution of layer-band like microstructure with the dendritic grains and the fully lamellar colonies along the deposition direction. With the enhancement in the line energy, the layer-band like feature gradually weakens, and the fully lamellar colonies increase. In addition, the discontinuous coarsen phenomenon and the discontinuous dynamic recrystallization occurred, and the anneal twin was also formed. On the other hand, tensile fractures were observed in the dendritic grains region, and the maximum tensile strength was achieved with the medium line energy. However, the elongation and microhardness are proportional to the line energy. With the elevation in the line energy, the elongation and microhardness gradually increases and decreases, respectively. The microstructure formation mechanism of as-fabricated TiAl alloy is analyzed systematically, and the fracture mechanics was also discussed in detail. The findings of this research contribute not only to the methodology for fabrication of TiAl alloys with the novel TW-DED-arc process, but also to the deep understanding on the regulation of the microstructural and mechanical characteristics of the additively manufactured TiAl alloys.

Piezoactive Bioorganic Diphenylalanine Films: Mechanism of Phase Formation.

Self-organized peptides are unique materials with various applications in biology, medicine, and nanotechnology. Many of these applications require fabrication of homogeneous thin films having high piezoelectric effect and sufficiently low roughness. Recently, a facile method for the controlled deposition of flat solid films of the most studied peptide, diphenylalanine (FF), has been proposed, which is based on the crystallization of FF in the amorphous phase under the action of water vapor. This method is very advantageous compared with crystallization from a liquid phase reported previously. Here, we thoroughly investigate the mechanism of solid-state transformation from the amorphous to crystalline phase. The study revealed that the process proceeds in two distinct stages, maintaining clamped condition of self-assembling building blocks that preserve the films' morphology and high piezoelectric activity. We emphasize the critical role of water diffusion that governs two-dimensional growth of crystalline domains in FF films, merging in very dense, flat, and homogeneous films. These findings open a wide perspective for using this methodology for the direct fabrication of biofilms from the amorphous phase. We thus expect the application of these films to various nanotechnological applications of self-assembled structures.

Gradient honeycomb metastructure with broadband microwave absorption and effective mechanical resistance

Multifunctional metastructure integrated broadband microwave absorption and effective mechanical resistance has attracted much attention. However, multifunctional performance is limited by the lack of theoretical approaches to integrated design. Herein, a multi-layer impedance gradient honeycomb (MIGH) was designed through theoretical analysis and simulation calculation, and fabricated using 3D printing technique. A theoretical calculation strategy for impedance gradient structure was established based on the electromagnetic parameter equivalent method and the multi-layer finite iterative method. The impedance of MIGH was analyzed by the theoretical calculation strategy to resolve the broadband absorption. Intrinsic loss mechanism of matrix materials and distributions of electric fields, magnetic fields and power loss were analyzed to investigate the absorption mechanism. Experimental results indicated that a 15 ​mm thick designed metastructure can achieve the absorption more than 88.9% in the frequency range of 2-18 ​GHz. Moreover, equivalent mechanical parameters of MIGH was calculated by integral method according to the Y-shaped model. Finite Element analysis of stress distributions were carried out to predict the deformation behavior. Mechanical tests demonstrate that MIGH achieved the compression modulus of 22.89 ​MPa and flexure modulus of 17.05 ​MPa. The integration of broadband electromagnetic absorption and effective mechanical resistance was achieved by the proposed design principle and fabrication methodology.

Comprehensive and Comparative Analysis of QCA-based Circuit Designs for Next-generation Computation

For the past several decades, VLSI design has been focused on lowering the size, power, and delay. As of now, this miniaturization does not seems to be a possible way to address the demands of consumers. Quantum Dot Cellular Automata (QCA) technology is a promising technique that is able to provide low-power high-speed circuits at nano-scale. Much work has been done in this area where the researchers have proposed a variety of combinational and sequential logic circuits for future computation. This article presents a concrete review of design approaches, logic circuits, clocking schemes, implementation tools, and possible fabrication methodologies presented so far in QCA technology. A critical comparative analysis is provided on the basis of reported performance parameters in the domain. The aim of this article is to collect all necessary information into a single source, highlight the research challenges to be taken in the near future, and enlighten the path for upcoming researchers in the area.

Additive manufacturing for ultra-high vacuum components: Leveraging photo-polymer resin technologies

Over the past two decades, Additive Manufacturing (AM) technologies, commonly known as 3D printing, have witnessed exponential advancements, transforming the paradigms of instrument design and fabrication across an array of scientific and engineering disciplines. The utilization of Computer-Aided Design (CAD) and monolithic machining within the AM framework offers unprecedented levels of flexibility, precision, and mechanical stability. These attributes not only facilitate complex geometrical constructions but also substantially streamline the overall fabrication workflows. In this study, we provide experimental evidence to substantiate the viability of employing Masked Stereolithography Additive Manufacturing (MSLA) technology in concert with commercially available photo-polymer resins for the fabrication of components that are compatible with Ultra-High Vacuum (UHV) conditions. Utilizing high-temperature photo-polymer resins and specialized post-printing treatments—including an approximate 24-h vacuum bake—we have achieved a vacuum level of approximately 1 × 10−9 torr for a solid component encompassing a volume up to 16 cm3. This methodology paves the way for the expedited and cost-effective production of complex, UHV-compatible devices, thereby offering a substantial departure from conventional manufacturing techniques. The wide-ranging applicability of this technology holds considerable potential for transformative impacts across diverse sectors of research and development. By leveraging UHV-compatible MSLA technology, both academic researchers and industrial professionals are poised to benefit from an efficient and adaptable fabrication methodology, consequently catalyzing cutting-edge advancements in their respective fields of inquiry.

Advances in Fabrication Technologies for the Development of Next-Generation Cardiovascular Stents.

Coronary artery disease is the most prevalent cardiovascular disease, claiming millions of lives annually around the world. The current treatment includes surgically inserting a tubular construct, called a stent, inside arteries to restore blood flow. However, due to lack of patient-specific design, the commercial products cannot be used with different vessel anatomies. In this review, we have summarized the drawbacks in existing commercial metal stents which face problems of restenosis and inflammatory responses, owing to the development of neointimal hyperplasia. Further, we have highlighted the fabrication of stents using biodegradable polymers, which can circumvent most of the existing limitations. In this regard, we elaborated on the utilization of new fabrication methodologies based on additive manufacturing such as three-dimensional printing to design patient-specific stents. Finally, we have discussed the functionalization of these stent surfaces with suitable bioactive molecules which can prove to enhance their properties in preventing thrombosis and better healing of injured blood vessel lining.

Durable superhydrophobic surface in wearable sensors: From nature to application

AbstractThe current generation of wearable sensors often experiences signal interference and external corrosion, leading to device degradation and failure. To address these challenges, the biomimetic superhydrophobic approach has been developed, which offers self‐cleaning, low adhesion, corrosion resistance, anti‐interference, and other properties. Such surfaces possess hierarchical nanostructures and low surface energy, resulting in a smaller contact area with the skin or external environment. Liquid droplets can even become suspended outside the flexible electronics, reducing the risk of pollution and signal interference, which contributes to the long‐term stability of the device in complex environments. Additionally, the coupling of superhydrophobic surfaces and flexible electronics can potentially enhance the device performance due to their large specific surface area and low surface energy. However, the fragility of layered textures in various scenarios and the lack of standardized evaluation and testing methods limit the industrial production of superhydrophobic wearable sensors. This review provides an overview of recent research on superhydrophobic flexible wearable sensors, including the fabrication methodology, evaluation, and specific application targets. The processing, performance, and characteristics of superhydrophobic surfaces are discussed, as well as the working mechanisms and potential challenges of superhydrophobic flexible electronics. Moreover, evaluation strategies for application‐oriented superhydrophobic surfaces are presented.

A Comprehensive Mechanical Characterization of Subject-Specific 3D Printed Scaffolds Mimicking Trabecular Bone Architecture Biomechanics.

This study presents a polymeric scaffold designed and manufactured to mimic the structure and mechanical compressive characteristics of trabecular bone. The morphological parameters and mechanical behavior of the scaffold were studied and compared with trabecular bone from bovine iliac crest. Its mechanical properties, such as modulus of elasticity and yield strength, were studied under a three-step monotonic compressive test. Results showed that the elastic modulus of the scaffold was 329 MPa, and the one for trabecular bone reached 336 MPa. A stepwise dynamic compressive test was used to assess the behavior of samples under various loading regimes. With microcomputed tomography (µCT), a three-dimensional reconstruction of the samples was obtained, and their porosity was estimated as 80% for the polymeric scaffold and 88% for trabecular bone. The full-field strain distribution of the samples was measured using in situ µCT mechanics and digital volume correlation (DVC). This provided information on the local microdeformation mechanism of the scaffolds when compared to that of the tissue. The comprehensive results illustrate the potential of the fabricated scaffolds as biomechanical templates for in vitro studies. Furthermore, there is potential for extending this structure and fabrication methodology to incorporate suitable biocompatible materials for both in vitro and in vivo clinical applications.

Template‐free Formation of Hybrid Dielectric for Flexible Capacitive Sensors with Wide‐Pressure‐Range Linear Detection

AbstractWearable and flexible capacitive pressure sensors have recently attracted significant attention in the fields of healthcare monitoring and intelligent human‐machine interaction. While considerable progress is made in achieving high‐pressure resolution over a wide linearity range, practical implementation still faces significant challenges due to complex manufacturing processes, as well as limited accuracy and stability for information transmission. To address these issues, inspiration is drawn from human skin and develop a new hybrid dielectric comprising a low‐permittivity (low‐k) micro‐cilia array and a high‐permittivity (high‐k) foam. Without assistance from an elaborate fabrication methodology, the template‐free method provides a cost‐effective and convenient way to realize the functional dielectric for flexible capacitive sensors. The hybrid dielectric exhibits a pressure‐induced series‐parallel conversion mechanism, enabling effective manipulation of the linear effective dielectric constant and controlled initial/resultant capacitance. Through systematic optimization, the sensor demonstrates a high sensitivity of 0.236 kPa−1 within an ultrabroad linearity range of up to 1100 kPa. Thanks to the unique characteristics of the hybrid dielectric, this device showcases potential applications in various domains including human joint motion analysis, healthcare monitoring, accurate message transmission, and convenient Morse code communication utilizing non‐overlapping capacitance signals.