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Amorphous oxide semiconductors (AOS) with high-mobility (>40 cm2/Vs) have recently become common for next-generation displays. While several candidates have been proposed, their practical use remains unclear because of their low reliability originating from bias stress instability such as negative bias stress (NBS) and positive bias stress (PBS). This study shows that CO-related impurity is a major source of NBS instability in amorphous InSnZnO (ITZO), a representative high-mobility AOS. CO-related impurity is formed at the surface of the ITZO layer after the photolithography process, according to thermal desorption spectroscopy and hard X-ray photoemission spectroscopy studies. It is shown that by using a simple method of UV ozone treatment at room temperature to remove these CO-related impurities, a high performance ITZO TFT with mobility of ~ 50 cm2/Vs and excellent bias stability, NBS (at −20 V, 3600 s): −0.25 V, PBS (+20 V, 3600 s): 0.15 V, can be realized. Almost the same results are obtained for Sn-free IZO-TFTs with mobility of ~ 70 cm2/Vs but the NBS instability caused by CO-related impurity does not appear for IGZO TFTs. This finding suggests that the bias stress instability by CO-related species is sensitive to high mobility AOS-TFTs.

The datasets simulate 100 points of sensitive locations that need to be geomasked and 1,000 points of fictitious residential locations. The simulations are conducted within a hypothetical study area with a size of 5 km by 4 km. Three spatial patterns are generated seperately for the sensitive and residential locations (random patterns for Cul-de-sacs; regular pattern for the conventional grid; clustered pattern to simulate the residential groups separated by parks and other landuse types).

Feature fusion modules from encoder and self-attention module have been adopted in semantic segmentation. However, the computation of these modules is costly and has operational limitations in real-time environments. In addition, segmentation performance is limited in autonomous driving environments with a lot of contextual information perpendicular to the road surface, such as people, buildings, and general objects. In this paper, we propose an efficient feature fusion method, Feature Fusion with Different Norms (FFDN) that utilizes rich global context of multi-level scale and vertical pooling module before self-attention that preserves most contextual information while reducing the complexity of global context encoding in the vertical direction. By doing this, we could handle the properties of representation in global space and reduce additional computational cost. In addition, we analyze low performance in challenging cases including small and vertically featured objects. We achieve the mean Interaction of-union(mIoU) of 73.1 and the Frame Per Second(FPS) of 191, which are comparable results with state-of-the-arts on Cityscapes test datasets., Comment: 5 pages, 4 figures

With rapid advancements in satellite technology, the amount of low earth orbit satellites has grown significantly which are primarily deployed for weather monitoring, earth observation or military purposes. Due to this reason, there has been an increased interest in enhancing the level of autonomy and cognition, onboard satellites to achieve optimal data collection. Optimal data is said to be collected when the satellites in a small sat constellation work together to collect information. This means that even if one of the satellites has missed out on some important information, the others can still collect them. A satellite constellation can be considered as a multi-agent reinforcement learning system. Having these agents coordinate with one another, can reduce the amount of time required to perform a task. The state-of-the-art satellite constellations follow a centralized coordination mechanism in which one primary satellite controls the rest of the satellites. This process is computationally more expensive and requires substantial communication between the satellites.It has a single point of failure and communication might be affected if the primary satellite fails. On the other hand, decentralized coordination allows agents to control their behavior themselves without the command of a supervised master. In this case, there is less inter-satellite communication which reduces the requirement for specialized onboard computational hardware. The proposal constitutes leveraging the Multi-Agent Deep Deterministic Policy Gradient [2] (MADDPG) algorithm to train the agents (satellites) to achieve optimal data collection. There are multiple use cases for the proposed solution such as illegal maritime activity tracking, natural disaster detection and assessing building damage after a natural disaster. The proposed solution focuses on tracking of ships in an extensively simulated environment for which a custom ship environment was created by leveraging OpenAI Gym [12]. By providing on-board autonomy, we aim to reduce frequent Earth Station (ES) communication significantly and enhance data collection capability.

This paper examines the neighborhood effect averaging problem (NEAP) in the evaluation of sociodemographic disparities in people’s air pollution exposures in Los Angeles using GIScience methods and activity-travel diary data of 3790 individuals. Spatial regression model results indicate that assessments of sociodemographic disparities in people’s air pollution exposures are erroneous when people’s daily mobility is ignored because of the different manifestations of neighborhood effect averaging for different social/racial groups. Therefore, to avoid erroneous conclusions in environmental inequality research, it would be critical to consider the NEAP in studies of

Extreme ultraviolet lithography (EUVL) is the most promising lithography technique for the 22 nm half-pitch and beyond. The EUV patterned masks work in a reflective mode and it has 40 to 50 pairs of MoSi multilayer to reflect EUV radiation. This multilayer is capped by a 2.5 nm Ru thin film to protect the MoSi multilayer. Since EUV mask does not have a pellicle which protects mask surface from the contaminants. Therefore, EUV mask is more vulnerable to particle contamination during lithography processing which is a major yield loss in device fabrication. No study has been reported on the effect of particle size on CD variation if they exist on EUV mask. The critical defect size, which can cause 10 % CD error, has to be removed from the mask surface. When the defect is located between line and space patterns on the mask, the reflectivity will be reduced due to defect absorption. Simulation predicted that 30 nm sized silica particles can cause 10 % CD error on 16 nm line and space pattern. Thus, these contaminant particles have to be removed from EUV mask surface for preventing CD variation. In order to evaluate the 30 nm sized silica particle removal test, we adopted 30 nm standard spherical silica particles. Actually, it is a challenge to evaluate 30 nm particles removal test without inspection tools. So, we used atomic micro scope (AFM) for the evaluation of these particles. The silica particles were intentionally deposited on Ru surface using spinning method. Cleaning test was performed with twin type megasnoic. 30 nm silica particles removal efficiency was drastically decreased as compared with 137 nm silica particles at 1 MHz megasonic cleaning. Because the megasonic cleaning force was reduced to ultra-fine particles due to boundary layer thickness. Therefore, higher megasonic cleaning force is required to remove ultra-fine particles to overcome boundary layer thickness. It is well known that the large cleaning force is induced, not only particle removal efficiency but also pattern damage will be increased. Thus, megasonic cleaning process without causing pattern damage has to be optimized. In this study, we shall discuss the effect of megasonic frequency on the removal of ultra-fine particles and pattern damage. Also, gas dissolved water and dilute alkali cleaning solution are adopted to high frequency megasonic cleaning process to achieve ultra-fine particles removal without pattern damage effectively. Figure 1

Growth of amorphous ZnO by B doping and their opto-electrical properties are reported. The B-doped ZnO (ZnO:B) films were grown by pulsed laser deposition using polycrystalline ZnO:B ceramic targets. Although the solubility limit of B in bulk ZnO polycrystal was ³4% ,1 8%-doped ZnO:B showed the shrinkage in the c-axis length. Preferentially (002)-oriented polycrystalline ZnO:B films were grown for the B concentration [B] ¯ 18%; while, amorphous ZnO:B films were obtained for [B] ³26%. It was found that the density of the amorphous ZnO:B film was smaller by 9% than that of crystalline ZnO (5.61g·cm ¹3 ), which is explained mainly by the incorporation of the light B atoms. The optical bandgap of the ZnO:B films increased with [B] and that of the amorphous ZnO:B film was ³3.38eV. The amorphous ZnO:B films have low free electron density of ³10 15 cm ¹3 , suggesting the existence of electron traps. Hall mobility of the amorphous ZnO:B [³1cm 2 (V·s) ¹1 ] was smaller than those of the poly

Inspired by the successful synthesis of alkaline-earth-metals-based electrides [Ca24Al28O64]4+(e–)4 (C12A7:e–) and [Ca2N]+:e– and high-throughput database screening results, we explore the potential for new electrides to emerge in the Sr–P system through a research approach combining ab initio evolutionary structure searches and experimental validation. Through employing an extensive evolutionary structure search and first-principles calculations, we first predict the new structures of a series of strontium phosphides: Sr5P3, Sr8P5, Sr3P2 and Sr4P3. Of these structures, we identify Sr5P3 and Sr8P5 as being potential electrides with quasi-one-dimensional (1D) and zero-dimensional (0D) character, respectively. Following these theoretical results, we present the successful synthesis of the new compound Sr5P3 and the experimental confirmation of its structure. Although density functional calculations with the generalized gradient approximation predict Sr5P3 to be a metal, electrical conductivity measurement r...

The defect on the extreme ultraviolet (EUV) mask can cause image quality degradation on the wafer and also poses a serious problem for achieving high volume manufacturing (HVM). Using a pellicle could decrease the critical size of a defect by taking the defect away from the focal plane of a mask. Considering the double pass transmission for the thickness of extreme ultraviolet lithography EUVL pellicle should be ~ nm thin. For ~ nm thin pellicle, the thermal stress by EUV light exposure may damage the pellicle. Therefore, an investigation of thermal stress is desired for reliable EUV light transmission through pellicle. Therefore, we calculated the total stress and compared with material maximum stress of the pellicle. Breaking or the safety of the pellicle could be determined by the induced total stress, however, the cyclic exposure heating could decrease the material maximum stress of the pellicle. The c-Si (crystalline silicon) has good mechanical durability than the p-Si (poly-crystalline silicon) under cyclic thermal exposure.

In addition to the development of extreme ultraviolet lithography (EUVL), studies on beyond extreme ultraviolet lithography (BEUVL), which uses radiation with a wavelength of 6.7 nm, are in progress for their application in high-volume manufacturing. The BEUV wavelength, which is much shorter than the EUV wavelength, improves the resolution of patterned features. However, suitable materials for the mask stack of BEUVL are still under development. In this study, the applicability of metallic materials, such as Ni, Co, Ir, W, and Ta, as the absorber in a binary-intensity BEUVL mask was evaluated. The mask-imaging properties were simulated by adopting a thickness that ensured a reflectivity of

The resist underlayer (UL) has been shown to beneficially impact the exposure latitude in photolithography techniques. As a result, the development of the resist UL is in progress for extreme ultraviolet lithography (EUVL) as well. Since the aspect ratio of patterns increases as the feature size decreases, a high-performance EUV UL is expected to be in high demand. In this study, we evaluated the optical properties of the EUV UL by using the lithography simulation tool PROLITH X5 (KLA-Tencor). We quantified the imaging properties of a 14 nm half-pitch (HP) line and space (L/S) pattern by varying the refractive index, extinction coefficient and thickness of the UL under 0.5 numerical aperture (NA) conditions with a conventional binary intensity mask. These simulations reveal that the number of photons absorbed in the photoresist increases as the refractive index of the UL decreases; this results from the increase in reflectivity from the UL/photoresist interface. Therefore, the line critical dimension (CD) mean value decreases and stochastic imaging properties improve in the observation plane. As the refractive index of the UL is reduced, however, the light intensity in resist and the distribution of photons is distorted by the standing wave effect, resulting in roughness and non-uniformity in the pattern sidewall. Therefore, the refractive index of the UL should be similar to that of the photoresist in order to get the optimized performance.

An asynchronous spread spectrum system called coded multiple chirp is proposed, and the possible spread spectrum overlay over an analog FM-TV signal is investigated by computer simulation. Multiple single-sloped up and down chirps are encoded by a pseudonoise code and decoded by dechirpers (pulse compression filters) followed by a digital code correlator. The performance of the proposed system, expressed in probability of bit error and code miss probability, is similar to that of FSK (frequency shift keying) using codewords if sufficient compression gain is used. When chirp is used to overlay an FM-TV channel, two chirp signals with data rate up to 25 kb/s could be overlaid in a 36 MHz satellite transponder without significant mutual interference. Performance estimates for a VSAT (very small aperture terminal) Earth station operating at C-band show that a 2.4 m antenna and 300 mW transmitter could send a 2.4 kb/s signal to a large central Earth station over an occupied channel. >

We suggest a new object-oriented functional language, OOId, which is based on a functional language Id and extended with object-oriented language features. We also discuss how to map OOId program onto DAVRID, which is a kind of multithreaded architecture based on the dataflow model. The comparison of execution time of two programs written in Id and OOId for the matrix multiplication problem, shows we can effectively run OOId program with just a little slow-down of execution time. In addition, the rate of slow-down is decreased, as the size of the matrix is larger. That means we can use good features of object-oriented language by paying just a little slow-down of execution time.

The performance of a nonlinear satellite channel using QPSK (Quaternary Phase Shift Keying) and MSK (Minimum Shift Keying) has been studied by computer simulation. In the simulation, the pseudo randomly generated input data stream modulates the carrier and this modulated carrier passes through the typical satellite communication link, that consists of a transmit earth station, a satellite transponder, and a receiving earth station. All the signals used in the simulation procedure are real-valued and are transformed back and forth between time and frequency domains depending on the necessity by the Fast Fourier Transform (FFT) or Inverse Discrete Fourier Transform (IDFT). The simulation result represented as average Bit Error Rate (BER) gives the basis for comparison of the performance in various link conditions such as linearity, nonlinearity, band-limited and noisy channels which are expected to be encountered in practical situations. Master of Science incomplete_metadata