Advanced Semiconductor Materials Research Articles

Optical design of reflective Bragg mirrors for EUV photolithography

In this article. we investigate the optical characteristics of reflective extreme-ultraviolet (EUV) mirrors for the application of lithography for 7 nm node and below. By using the conventional quarter-wavelength stacked Bragg reflective configuration of Si-based metal multilayers centered at soft x-ray 13.5 nm, the maximum reflection is numerically computed to be approximately 0.7 at nearly normal incidence, which is consistent to the typical values reported by Advanced Semiconductor Materials Lithography (ASML) for Mo/Si stacked multilayers. The full width half maximum (FWHM) bandwidth is 0.65∼0.78 nm. In our numerical simulation, moreover, we find Nb/Si reflective mirrors can be potentially utilized to replace Mo/Si stacked multilayers in order to harvest more EUV light inside the scanners.

Remarkable Enhancement of the Hole Mobility of Novel DA-D'-AD Small Molecules by Thermal Annealing: Effect of the D'-Bridge Block.

Conjugated small molecules are advanced semiconductor materials with attractive physicochemical and optoelectronic properties enabling the development of next-generation electronic devices. The charge carrier mobility of small molecules strongly influences the efficiency of organic and hybrid electronics based on them. Herein, we report the synthesis of four novel small molecules and their investigation with regard to the impact of molecular structure and thermal treatment of films on charge carriers mobility. The benzodithiophene-containing compounds (BDT) were shown to be more promising in terms of tuning the morphology upon thermal treatment. Impressive enhancement of hole mobilities by more than 50 times was found for annealed films based on a compound M4 comprising triisopropylsilyl-functionalized BDT core. The results provide a favorable experience and strategy for the rational design of state-of-the-art organic semiconductor materials (OSMs) and for improving their charge-transport characteristics.

Utilizing Dip-Coating to Fabricate Gate Dielectric and Semiconductor for Thin-Film Transistors

The potential applications of advanced electronic materials in large-area, printable, and flexible electronics have generated significant interest. However, creating high-performance, low-voltage thin-film transistors (TFTs) for these applications remains difficult due to a lack of advanced gate dielectric and semiconductor materials that meet both ease-of-fabrication requirements and high electrical performance. In this study, we present high-performance gate dielectric thin-films, which were fabricated using a facile solution-based technique, and then employed to realize low operating voltage organic and metal oxide semiconductor-based thin-film transistors. The high-k oxide gate dielectrics were produced via a simple dip-coating method, resulting in the formation of thin-oxide layers. These novel oxide gate dielectrics demonstrated exceptional dielectric properties, with large capacitances (up to 430 nF/ cm2), low-level leakage current densities (< 3 × 10-8A/cm2 at 4 V), featureless morphology (rms roughness < 0.36 nm), and high transparency (> 85%). Consequently, these dip-coated gate dielectrics can be incorporated into thin-film transistors, utilizing pentacene as p-type organic semiconductors. Furthermore, by employing dip-coating, indium oxide and indium-gallium-zinc oxide can be utilized as n-type inorganic semiconductors, allowing for the fabrication of low-voltage operation and high-performance inorganic TFTs. The resulting TFTs functioned at ultralow voltages (< ± 2 V) and achieved high transistor performance (hole mobility: 0.28 cm2V-1·s-1, electron mobility: ~2.0 cm2V-1·s-1 and on/off current ratio >105).

Advanced semiconductor materials in power electronic switches for energy-efficient converters in an electric vehicle charging system with closed-loop FOPID control

The growth in consumer use of electric vehicles is influencing the electrification of transportation in greener and more energy-efficient ways. The availability of high-speed charging stations is crucial to the commercial viability of electric vehicles (EVs). This article examines the development, evaluation, and next steps for several Vienna converter topologies for DC fast-charging systems. The designs and evaluations of these converters are provided, reviewed, and contrasted. The work primarily focuses on several Vienna rectifier topologies on DC quick charging stations that result in fewer CO2 emissions in EV charging stations, aiding in climate action and sustainable development goals. Open-loop and closed-loop charging systems are also discussed in this study to provide improved charging efficiency. The closed-loop system is developed with PI and FOPID controllers; the system is simulated in MATLAB Simulink, and the outputs are obtained to produce a system with higher efficacy. The outputs of the two controllers were compared in terms of time domain metrics like rise time, peak time, settling time, and steady-state error. Results are compared, and it is discovered that the closed-loop charging system with the Vienna rectifier and FOPID controller works better in every way. When charging an EV battery, the performance and efficiency of the Vienna converter circuit, a power electronic switching device, depends on its material qualities. Typically, these switches are constructed from silicon. Switching devices use broad-band semiconductors because of developments in material science and a need for higher performance. This work also discusses the semiconductor material used to create the power electronic switches used in the Vienna Converter.

A Hybrid Pressureless Silver Sintering Technology for High-Power Density Electronics

Aerospace and defense applications present unique challenges for material suppliers. As increasing adoption of advanced semiconductor materials and Diverse Accessible Heterogeneous Integration technologies, power density of defense and aerospace devices increases rapidly. Traditional die-attaching technology is becoming an increasingly limiting factor in microelectronics packaging for the next generation aerospace and defense systems. Metal particle sintering creates a porous metal foam, which can significantly enhance heat transfer within the sintered material. However, the traditional silver sintering requires very high sintering temperatures that cannot be tolerated by typical microelectronics devices. In addition, the sintered metal foam contains open-cell pores that can absorb/entrap moisture and dusts, which poses a reliability risk. This article introduces an advanced hybrid silver sintering material, which incorporates highperformance silver sintering with high reliability and process-friendly of epoxy-based die-attaching technology. This hybrid sintering paste can be processed without applying any pressures in temperature ranges that are normal in microelectronics packaging processes. Preliminary experimental studies, including Scanning Electron Microscopic study, volume resistivity tests, die shear strength tests, and thermal resistance tests, were performed for developing a low temperature sintering schedule that is compatible with normal assembly processes of high-power density electronics devices. The results indicated that the hybrid material could achieve silver sintering at 150 degrees C and offer 36 enhancement on thermal performance comparing with a widely used die-attach material.

Modulating the Self‐Assembly of Coplanar D–π–D Hole‐Transporting Materials via Alkyl Chain Engineering for Efficient and Stable Inverted Perovskite Solar Cells

Rational introduction of flexible alkyl chains into rigid conjugated molecules is a facile but effective strategy to develop advanced organic semiconductor materials for considerable enhancement of photovoltaic performance. Herein, seven hole‐transporting materials (HTMs) via attaching ethyl, hexyl, or ethylhexyl to benzodithiophene π‐linker and bromoethyl, bromobutyl, or bromohexyl to phenoxazine donor (D), respectively, named B2P2, B6P2, B8P2, B6P4, B2P6, B6P6 (N01), and B8P6, are reported. Joint differential scanning calorimetry measurements and thin‐film absorption spectra of representative HTMs, B8P6, B6P4, and B2P2 reveal that alkyl chain modulation on coplanar D–π–D HTMs enables synchronous optimization of their solution processability, molecular packing, and thermal phase transition. Consequently, benefiting from the favorable self‐assembly and surface characteristics of hole‐transporting layers and further induced superior upper perovskite‐growth, B8P6‐ and B6P4 ‐based inverted perovskite solar cells exhibit decent power conversion efficiencies of 20.67% and 20.13%, respectively, prior to that of amorphous B2P2 (19.04%). Analysis on steady‐state/transient photoluminescence spectra and light intensity‐dependent short‐circuit photocurrent and open‐circuit voltage (Voc) demonstrates that more ordered assemblies of HTMs obtained via alkyl chain engineering can facilitate efficient interfacial charge transport/extraction and inhibit detrimental charge recombination, accounting for an enhanced Voc and fill factor.

Novel Push-Pull Benzodithiophene-Containing Polymers as Hole-Transport Materials for Efficient Perovskite Solar Cells

Donor-acceptor conjugated polymers are considered advanced semiconductor materials for the development of thin-film electronics. One of the most attractive families of polymeric semiconductors in terms of photovoltaic applications are benzodithiophene-based polymers owing to their highly tunable electronic and physicochemical properties, and readily scalable production. In this work, we report the synthesis of three novel push-pull benzodithiophene-based polymers with different side chains and their investigation as hole transport materials (HTM) in perovskite solar cells (PSCs). It is shown that polymer P3 that contains triisopropylsilyl side groups exhibits better film-forming ability that, along with high hole mobilities, results in increased characteristics of PSCs. Encouraging a power conversion efficiency (PCE) of 17.4% was achieved for P3-based PSCs that outperformed the efficiency of devices based on P1, P2, and benchmark PTAA polymer. These findings feature the great potential of benzodithiophene-based conjugated polymers as dopant-free HTMs for the fabrication of efficient perovskite solar cells.

Organic Semiconductor Single‐Crystal Light‐Emitting Transistors

AbstractOrganic semiconductor single crystals, with the unique advantages of high carrier transport properties, high optical quality, and low defect density, are ideal candidates for constructing high‐performance organic light‐emitting transistors (OLETs) and advancing their related potential applications, including smart displays, micro‐nano light sources, organic electrically pumped lasers, and integrated photonic circuits. Recently, significant progress has been made in organic semiconductor single‐crystal light‐emitting transistors (OSSCLETs), particularly high‐mobility emissive organic semiconductor single crystals, high‐performance light‐emitting transistors, and color‐tunable organic semiconductor single crystals and OLETs. In this review, the exciting advances in OSSCLETs are summarized in terms of advanced organic semiconductor materials, high‐quality organic semiconductor single crystals, advanced device technologies, and high‐performance light‐emitting transistors. Finally, the challenges and prospects of OSSCLETs as well as promising research directions in this field are briefly summarized.

Special Issue: Advanced Semiconductor Materials and Films: Properties and Applications

Advanced semiconductor materials and films are building blocks for multifunctional devices and circuits, integrated optoelectronic chips, and high-throughput communications, which have proved basic material platforms for nanoscience and technologies [...]

Advanced Semiconductor Alloy Alxin1-Xp for Engineering and Medicine

Doped Advanced semiconductor materials with different properties are useful for early diagnosis and improved treatment in medical research. This is essential for advanced medical technology and lower mortality rates. New research on impurity-doped nano crystals is important. These dopants can directly affect electron transport in semiconductors, tune the optical properties of nano materials in desirable ways, and impart specific properties to the host. In this research report, we first discuss the factors that need to be considered to systematically control the production of these doped semiconductor materials, then describe various doped materials and typical synthetic approaches and techniques. Innovations in nanotechnology and materials design and their application in early diagnosis and treatment are believed to minimize the number of new cases of related diseases and reduce mortality.1,2,3 From natural to man-made materials, Doped semiconductor nanostructures, including inorganic and organic semiconductors, are increasingly attracting the attention of researchers and scientists worldwide

Atomic-scale imaging of dopant atoms in Si-doped GaN

Determination of the concentration and distribution of trace impurity is a key factor in the manufacture of advanced semiconductor materials and is of great significance to the development of sophisticated electronics. Doping has a great influence on the performance of GaN, and a small change in the impurity content will lead to the degradation of the device performance, or even cause device failure. Determining the trace impurity and spatial distribution is therefore critical to understanding and adequately tuning functional properties. In this study, the two-dimensional distribution of Si-doped in GaN was determined by atomic resolution scanning transmission electron microscopy high angle annular dark field (STEM-HAADF) image combined with EDS mapping. Furthermore, STEM image simulation was used to estimate the distribution of trace impurity in the depth direction. This method may be useful for the determination of trace impurity concentration and distribution in semiconductor materials.

Electronic and optical properties of two-dimensional GaN/ZnO heterojunction tuned by different stacking configurations

Two-dimensional (2D) semiconductors show novel electronic and optoelectronic applications due to their excellent performance. The van der Waals (vdW) heterostructures are also a new method for the design of low dimensional optoelectronic devices. However, their fundamental electronic structure and optical properties are sensitive to stacking configurations. Herein, we perform systematic first-principle calculations for monolayer GaN and ZnO by six different stacking styles. The results suggest that the bonding type and stability vary with the stacking method. Chemical bonding and vdW interaction are respectively observed in different models. However, the carrier mobilities for different models are all enhanced after integration. Both type I and II band alignment can be generated from different stacking models. The optical properties suggest high absorptivity in the solar-blind region. This study is an early stage for the design and synthesis of photodetectors or solar cells based on 2D GaN/ZnO heterojunctions and also opens a far-ranging research interest in optoelectronic materials and devices with more advanced semiconductor materials.

To keep or divest a division: Canon’s strategy in an oligopolistic market

The issue in this teaching case is the future of the Lithography Division of Canon. The case is situated in 2015 when this division represents around 7.5% of the company’s assets, 13.8% of its sales, and 10% of its capital expenditures. The division is loss-making. This issue is faced by two persons in the organization: the CEO and the CFO of Canon. The CEO would like to keep the division, while the CFO prefers to divest it. The case is particularly interesting because of the market structure: the division operates in the lithography market, which is a clear example of an oligopoly. The case can be used in Strategy, Technology, or Digital Business courses in MSc or MBA programs. The learning objectives of the case are (1) combining information provided via academic journals with facts from the case and the collective knowledge and creativity of a team of students, (2) analyzing the collected information and building a case with strong arguments, (3) creating a convincing strategic plan including a persuasive presentation, and (4) practicing the skills of presenting. The information provided in this case is based on the annual reports of Advanced Semiconductor Materials Lithography (ASML), Canon, and Nikon, and on other publicly available information on the lithography industry. The case itself is fictional. The authors are not aware of any discussions within Canon about the future of the company’s lithography division.

Synergistic effect of Ru embedded 2D Ti3AlC2 binary cocatalyst with porous g-C3N4 to construct 2D/2D Ru-MAX/PCN heterojunction for enhanced photocatalytic H2 production

Developing engineering advanced semiconductor materials with low cost and high efficiency have great importance in solar assisted hydrogen production. In this work, well-designed Ru modulated oxygen defective Ti3AlC2 MAX multilayers binary cocatalyst with porous g-C3N4 has been fabricated through ultrasonic approach. Synergistic effect of Ru/Ti3AlC2 enabling proficient charge carrier transportation for significantly enhanced H2 production. The optimized 3Ru-15Ti3AlC2/g-C3N4 exhibited 1445 µmol g−1h−1 of H2 evolution rate which is 7.67 and 16.35 times more than using 15Ti3AlC2/CN and CN samples. The obvious augmented H2 production can be attributed to efficient charges separation with higher light absorption due to Ru/Ti3AlC2 binary cocatalyst. The catalyst loading and sacrificial reagents further confirms mass transfer and surface-active sites exposed to light irradiation. This study provides new approach to construct heterojunction of 2D/2D self-assembly, enabling synergistically improved quantum yield with higher cyclic stability and can be further explored in other solar energy assisted applications.

Topics in the mathematical design of materials.

We present a perspective on several current research directions relevant to the mathematical design of new materials. We discuss: (i) design problems for phase-transforming and shape-morphing materials, (ii) epitaxy as an approach of central importance in the design of advanced semiconductor materials, (iii) selected design problems in soft matter, (iv) mathematical problems in magnetic materials, (v) some open problems in liquid crystals and soft materials and (vi) mathematical problems on liquid crystal colloids. The presentation combines topics from soft and hard condensed matter, with specific focus on those design themes where mathematical approaches could possibly lead to exciting progress. This article is part of the theme issue 'Topics in mathematical design of complex materials'.

Heat Sink Design for WBG Power Modules Based on Fourier Series and Evolutionary Multi-Objective Multi-Physics Optimization

Optimal heat dissipation in power modules can significantly increase their power density. Removing the generated heat is critical for capturing the benefits of advanced semiconductor materials and improving the reliability of the device operation. This study proposes a design optimization method for liquid-cooled heat sinks that use a Fourier analysis--based tool and an evolutionary optimization algorithm to optimize the heat sink geometry for specified objectives. The optimized heat sink geometry was compared with state-of-the-art solutions in the literature based on finite element analysis of different designs. The proposed methodology can develop complex geometries that outperform conventional heat sink geometries. Optimized heat sink design from the proposed method was fabricated and tested in an experimental setup under representative operating conditions. The experimental setup was also modeled in the finite element model that was used for the proposed heat sink optimization method. The experimental results show that developed finite element models can predict the thermal and flow performance of the complex design with high fidelity, and the results validate the proposed design approach.

Boosting charge spatial separation efficiency for catalytic H2 bubble evolution under macroscopic spontaneous polarization electric field

Serious recombination of photo-irradiated electrons ( e − ) and holes ( h + ) over photocatalysts restricts solar energy conversion, and directional transfer of e − / h + to reduction/oxidation locations respectively and simultaneously, is enormously difficult under the shackle of Coulomb field. Herein, internal spontaneous polarization electric field (ISPEF) has been constructed by coordination between 4 d 10 orbit of Cd 2+ and sp 2 -hybridized N to induce a non-overlapping state of two opposite charge centers in g -C 3 N 4 , which could thus boost charge spatial division and migration. The significantly improved efficiency for H 2 evolution, accompanying by consecutive emission of visual H 2 bubbles was realized. Photo-irradiated charge spatial separation and photocatalytic mechanism within ISPEF of CdC 3 N 4 was firstly confirmed by theory prediction and Hall effect characterization. The study strategy supplies a novel perspective to design polarized semiconductor materials for significantly effective solar energy transformation, which will bring about another research highlights for constructing efficiently advanced semiconductor materials. • Internal spontaneous polarization electric field (ISPEF) was constructed in g -C 3 N 4 . • Strong ISPEF boosts charge spatial separation and directional transfer effectively. • g -C 3 N 4 was polarized by coupling Cd 2+ 4 d 10 orbit with its sp 2 -hybridized N. • Visual H 2 bubbles were released over photocatalysts within ISPEF. • Theoretical calculation and Hall effect test were adopted to confirm ISPEF action.

Main and side reaction design exceeding the theoretical upper limit of chemical vapor deposition rate

Chemical engineering is a branch of engineering that brings together the principles of chemistry, physics, mathematics and biology to use, produce, design and transform energy and materials. Chemical engineering expert Professor Hitoshi Habuka, who is based at the Faculty of Engineering, Division of Materials Science and Chemical Engineering, Yokohama National University in Japan, is leading a team which is interested in creating advanced semiconductor materials through reaction engineering. One of their focuses in recent years has been on exceeding the epitaxial growth rate limit. Epitaxy - which is an important technique to prepare a crystalline film on a single-crystalline substrate - is essential to the manufacturing of devices and circuits association with electronics and photonics.

Strategic Study on the Development of Advanced Semiconductor Materials and Auxiliary Materials in China

The rapid development of the third-generation semiconductor materials represented by SiC and GaN offers China a strategic opportunity to realize the independent control over its advanced semiconductor materials and auxiliary materials sector and to ensure the security of relevant industrial systems. In this paper, we analyze the development status of semiconductor materials and auxiliary materials in China and abroad, propose the idea of systematic, upstream–downstream coordinated, and sustainable development, and set the development goals for these materials by 2025 and 2035. To promote the development of advanced semiconductor materials and auxiliary materials in China, we suggest the establishment of a project for realizing independent control over key material and equipment of integrated circuit; a platform that provides integrated tests for SiC and GaN semiconductor materials, auxiliary materials, processes, and equipment; and application demonstration projects for advanced semiconductor materials in the fifth-generation mobile communication, energy internet, and new energy vehicle fields. Demand analysis regarding these projects is conducted and specific project objectives and tasks are proposed correspondingly. To promote the innovative development of the semiconductor industry, China should adhere to government guidance to facilitate the integration of domestic advantageous resources, grasp the “More Than Moore” opportunity of to lay out the next-generation integrated circuit technologies, and construct an innovation chain to further improve the innovation ecology.

Rule based Text Extraction from a Bibliographic Database

<p>The emergent concept of ‘ Big Data’ has shifted the paradigm from information retrieval to information extraction techniques. The information extraction techniques enables corpus analysis to draw useful interpretations and its possible applications. Selection of appropriate information extraction technique depends upon the type of data being dealt with and its possible applications. In an R&D environment, the published information is considered as an authenticated benchmark to study and analyse the growth pattern in that field of science, medicine, business. A rule based information extraction process, on the selected data extracted from a bibliographic database of published R&D papers is proposed in this paper. Aim of the study is to build up a database on relevant concepts, cleaning of retrieved data and automate the process of information retrieval in the local database. For this purpose, a concept based ‘subject profiles’ in the area of advanced semiconductors as well as the rules for text extraction from metadata retrieved from the bibliographic database was developed. This subset was used as an input to the knowledge domain to support R&D in the area of ‘advanced semiconductor materials and devices’ and provide information services on Intranet. Study found that concept based pattern matching on the datasets downloaded yielded better results as compared to the results by using the controlled vocabulary of the source database .</p>