Repeatability of Epitaxial Growth of n-Type 4H-SiC Films by High Speed Wafer Rotation Vertical CVD Tool

2019 ◽  
Vol 963 ◽  
pp. 101-104 ◽  
Author(s):  
Yoshiaki Daigo ◽  
Akio Ishiguro ◽  
Shigeaki Ishii ◽  
Yoshikazu Moriyama ◽  
Kunihiko Suzuki ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Carrier Concentration ◽  
High Speed ◽  
Epitaxial Films ◽  
Short Term ◽  
Gas Nozzle ◽  
Sic Films ◽  
Growth Experiments ◽  
Nozzle Structure

N-type 4H-SiC homo-epitaxial films were grown by high speed wafer rotation vertical CVD tool, and both short term repeatability and long term repeatability of epitaxial growth were investigated. In the short term repeatability investigated by 6 epitaxial wafers chosen from successively grown 12 epitaxial wafers using same recipe, it was found that total variation of thickness and carrier concentration for all measurement points of 6 wafers is 1.44 and 4.64 % respectively, which indicates excellent repeatability as well as high uniform thickness and carrier concentration. In the long term repeatability investigated by a very large number of growth experiments, probability achieving target uniformity of thickness and carrier concentration of the SiC films was increased up to 1.32 times by optimizing gas nozzle structure in gas inlet compared with in the case of conventional gas nozzles. Moreover, adjustment range of C/Si ratio necessary to achieve target uniformity of thickness and carrier concentration of the films was considerably reduced to 22 % by optimized gas nozzles.

Improvement of Repeatability on N-Type 4H-SiC Epitaxial Growth by High Speed Wafer Rotation Vertical CVD Tool

2020 ◽  
Vol 1004 ◽  
pp. 78-83
Author(s):  
Yoshiaki Daigo ◽  
Akio Ishiguro ◽  
Shigeaki Ishii ◽  
Takehiko Kobayashi ◽  
Yoshikazu Moriyama
Keyword(s):  
Carrier Concentration ◽  
High Speed ◽  
Epitaxial Films ◽  
The Other ◽  
Short Term ◽  
Wafer Thickness ◽  
Sic Film ◽  
Sic Films ◽  
Effect Of Surface

N-type 4H-SiC homo-epitaxial films were grown on 150 mm diameter wafers by high speed wafer rotation vertical CVD tool, and effect of surface C/Si ratio on short-term and long-term repeatability of the SiC films was investigated. By tuning of growth condition, high uniform SiC film with in-wafer thickness uniformity of ±2.8 % (1.6 % σ/mean) and carrier concentration uniformity of ±3.1 % (1.9 % σ/mean) was successfully grown at higher introduced C/Si ratio of about 1.80, which corresponds to surface C/Si ratio higher than 1.0 on the whole wafer. This result was comparable to the film grown at lower introduced C/Si ratio of about 1.35, which corresponds to surface C/Si ratio lower than 1.0 on the whole wafer. On the other hand, the films on 13 wafers successively grown at higher introduced C/Si ratio indicated low fluctuation from 1.85 to 3.09 % (σ/mean), and the short-term repeatability of the in-wafer carrier concentration uniformity of the films grown at higher introduced C/Si ratio was improved compared with the films grown at lower introduced C/Si ratio. Additionally, in-wafer carrier concentration uniformity of the films on 171 wafers grown at higher introduced C/Si ratio showed 75 % quartile of 4.26 % (σ/mean), and this result was greatly superior to that of 8.21 % (σ/mean) for the films on 130 wafers grown at lower introduced C/Si ratio.

A dynamic and robust image processing based method for measuring the yarn diameter and its variation

2014 ◽  
Vol 84 (18) ◽  
pp. 1948-1960 ◽  
Author(s):  
Mohamed Eldessouki ◽  
Sayed Ibrahim ◽  
Jiři Militky
Keyword(s):  
High Speed ◽  
Dynamic Change ◽  
Effective Property ◽  
Periodic Variation ◽  
Short Term ◽  
Reasonable Time ◽  
Yarn Diameter ◽  
Fabric Structure ◽  
Robust Image

The yarn diameter is an effective property in determining fabric structure and processing settings. There are different systems of measuring the yarn diameter; among them is the image analysis of the yarn’s microscopic images. This method is considered to be more precise than other methods, but it is “static” in nature as it measures the property at scattered intervals and does not reflect the continuous variation of the yarn diameter. The goal of the current work is to measure the yarn diameter and its variation over a long length of yarn at fixed intervals to consider the “dynamic” change in the property. To achieve this goal, a high-speed camera (HSC) with a proper magnification was used to capture the images of the yarn and a new robust algorithm was developed to analyze the massive amount of yarn pictures in a reasonable time. The collected data for the yarn diameter were analyzed and compared to the results of the commercial Uster Evenness Tester IV. The results of the HSC were very comparable to the results of Uster and they were able to detect the short-term, the long-term, and the periodic variation of the yarn diameter.

Two-step epitaxial growth of NbON (100) thin films on rutile-type TiO2 (101) substrates and reduction of residual carrier concentration by RF reactive sputtering

CrystEngComm ◽  
2019 ◽  
Vol 21 (23) ◽  
pp. 3552-3556 ◽  
Author(s):  
Ryosuke Kikuchi ◽  
Toru Nakamura ◽  
Yasushi Kaneko ◽  
Kazuhito Hato
Keyword(s):  
Thin Films ◽  
Epitaxial Growth ◽  
Carrier Concentration ◽  
Reactive Sputtering ◽  
Epitaxial Films ◽  
Step Growth

Two-step growth makes it possible to grow NbON epitaxial films and minimize anion-related defects in the NbON films.

scholarly journals PENERAPAN AUTOREGRESSIVE DISTRIBUTED LAG DALAM MEMODELKAN PENGARUH INFLASI, PERTUMBUHAN EKONOMI, DAN FDI TERHADAP PENGANGGURAN DI INDONESIA

2020 ◽  
Vol 9 (3) ◽  
pp. 250
Author(s):  
Jumhur Jumhur
Keyword(s):  
Economic Growth ◽  
Foreign Investment ◽  
High Speed ◽  
Time Series Data ◽  
Series Data ◽  
Short Term ◽  
Distributed Lag ◽  
Autoregressive Distributed Lag ◽  
Short And Long Term

This study aims to examine the effect of inflation, economic growth, and foreign investment on unemployment in Indonesia. Using the autoregressive distributed lag (ARDL) analysis method to analyze the 1991-2018 time series data collected from the World Bank's World Development Indicators database. The results found that inflation has a negative and significant effect in the short term but not significant in the long term in Indonesia. Economic growth has a negative and significant effect on both short and             long-term unemployment in Indonesia, and foreign investment has a negative and significant effect on both short and long-term unemployment in Indonesia. Through the ARDL model, this research is able to prove that inflation, economic growth, foreign investment, and budgeting are proven to have long-term cointegration or move together in the long term. The four variables also have a dynamic short-term relationship that has a fairly high speed of adjustment towards equilibrium per year. Based on the results, policymakers, in this case the government must provide a conducive investment environment by eliminating the structural rigidity that exists in the economy to attract investment, both foreign and domestic investment, to encourage economic growth and create jobs in Indonesia.

Epitaxy of SiC Films on Sapphire by Laser CVD

1987 ◽  
Vol 97 ◽  
Author(s):  
Hirohide Nakamatsu ◽  
Shichio Kawai
Keyword(s):  
Epitaxial Growth ◽  
Excimer Laser ◽  
Low Pressure ◽  
Epitaxial Films ◽  
Twin Structure ◽  
Arf Excimer Laser ◽  
Carrier Gases ◽  
Laser Cvd ◽  
Sic Films ◽  
Peeling Off

ABSTRACTArF excimer laser CVD was performed in a very-low pressure reactor. C2H2 and Si2H6 were used as source gases and carrier gases were not used. Epitaxial 3C-type SiC(111) grew parallel to α-Al2O3 (0001) substrate. It had a twin structure. Mismatch between the lattice parameters was estimated to be 12%. The epitaxial growth occurred down to 980°C and the films about 0.5μm in thickness grew at 1150°C for 30 minutes. Unirradiated films were polycrystalline or spontaneously peeling-off epitaxial films, while irradiated ones were strongly adherent epitaxial films.

scholarly journals Research on Volleyball Video Intelligent Description Technology Combining the Long-Term and Short-Term Memory Network and Attention Mechanism

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yuhua Gao ◽  
Yong Mo ◽  
Heng Zhang ◽  
Ruiyin Huang ◽  
Zilong Chen
Keyword(s):  
Language Processing ◽  
Visual Information ◽  
High Speed ◽  
Short Term Memory ◽  
Attention Mechanism ◽  
Short Term ◽  
Term Memory ◽  
Video Description ◽  
Memory Network

With the development of computer technology, video description, which combines the key technologies in the field of natural language processing and computer vision, has attracted more and more researchers’ attention. Among them, how to objectively and efficiently describe high-speed and detailed sports videos is the key to the development of the video description field. In view of the problems of sentence errors and loss of visual information in the generation of the video description text due to the lack of language learning information in the existing video description methods, a multihead model combining the long-term and short-term memory network and attention mechanism is proposed for the intelligent description of the volleyball video. Through the introduction of the attention mechanism, the model pays much attention to the significant areas in the video when generating sentences. Through the comparative experiment with different models, the results show that the model with the attention mechanism can effectively solve the loss of visual information. Compared with the LSTM and base model, the multihead model proposed in this paper, which combines the long-term and short-term memory network and attention mechanism, has higher scores in all evaluation indexes and significantly improved the quality of the intelligent text description of the volleyball video.

Measures of vibration exposure for a high-speed craft crew

2011 ◽  
Vol 225 (4) ◽  
pp. 338-349 ◽  
Author(s):  
K Garme ◽  
L Burström ◽  
J Kuttenkeuler
Keyword(s):  
High Speed ◽  
Whole Body ◽  
Vibration Exposure ◽  
Short Term ◽  
Transient Vibration ◽  
Static Compression ◽  
Acceleration Signal ◽  
Exposure Data ◽  
Iso 2631

The paper compares measurement-based measures for human vibration exposure. Data were collected during sea trials on a 10 m, 50 kn coastguard craft equipped with a three-axial accelerometer at the coxswain seat and with vertically mounted gauges measuring the acceleration of the cockpit floor. The ISO 2631-1:1997 measures of vibration (namely the root-mean-square (r.m.s.) value of the whole-body vibration (determined from the frequency-weighted acceleration signal), the maximum transient vibration value (MTVV), and the vibration dose value), the ISO 2631-5:2004 measure (namely the daily equivalent static compression dose Sed), and also statistically based measures to evaluate the acceleration magnitude are compared and discussed with respect to their ability to identify the mitigating effect of the suspension seat and how the different measures rank the severity of the high-speed craft (HSC) ride. The paper concludes that the r.m.s. value and the MTVV are unsuitable for evaluation of the conditions aboard while the other investigated measures show potential in this respect. Further the approach of ISO 2631-5:2004 taking both the short-term and the long-term perspectives on the human exposure to vibration is concluded to be the most mature method well suited to evaluation of HSC conditions.

Global Performance and Mooring Analysis Using Long Term Analysis Methodology

2016 ◽  
Author(s):  
Mubing Xu ◽  
Anil Sablok ◽  
Oddgeir Dalane
Keyword(s):  
High Speed ◽  
Line Tension ◽  
Mooring Line ◽  
Return Periods ◽  
Short Term ◽  
Analysis Methodology ◽  
Extreme Response ◽  
Global Performance ◽  
Term Analysis

The long term analysis is performed to predict the hull global motion and mooring strength of a Spar platform and the results from long term analysis are compared with the predictions from the short term analysis. The long term motions are also used to investigate the long term riser strength response in Ref. [5]. The results includes the lateral offset, heel angle, heave motion and the mooring line tension at the fairleads. In the short term analysis, the environment events with various return periods and various realizations are considered for each environment load. The Gumbel fitting is used to predict the extreme response. In the long term analysis methodology, the prediction of the global performance and the mooring tension are based on 56-year hindcast wind and wave data with 3-hour intervals. Weibull fitting is used to predict the extreme response for various return periods. The comparison between the long term and the short term predictions indicate that the short term predictions are generally conservative compared to the more accurate, but computationally expensive long term analysis method. The long term methodology is not widely adopted currently due to the computation inefficiency. However, it is expected that this long term methodology could provide a better option in the future with the consideration of its accuracy and the application of high speed computer.

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