• 제목/요약/키워드: Defect Density

검색결과 460건 처리시간 0.036초

Nature of Surface and Bulk Defects Induced by Epitaxial Growth in Epitaxial Layer Transfer Wafers

  • Kim, Suk-Goo;Park, Jea-Gun;Paik, Un-Gyu
    • Transactions on Electrical and Electronic Materials
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    • 제5권4호
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    • pp.143-147
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    • 2004
  • Surface defects and bulk defects on SOI wafers are studied. Two new metrologies have been proposed to characterize surface and bulk defects in epitaxial layer transfer (ELTRAN) wafers. They included the following: i) laser scattering particle counter and coordinated atomic force microscopy (AFM) and Cu-decoration for defect isolation and ii) cross-sectional transmission electron microscope (TEM) foil preparation using focused ion beam (FIB) and TEM investigation for defect morphology observation. The size of defect is 7.29 urn by AFM analysis, the density of defect is 0.36 /cm$^2$ at as-direct surface oxide defect (DSOD), 2.52 /cm$^2$ at ox-DSOD. A hole was formed locally without either the silicon or the buried oxide layer (Square Defect) in surface defect. Most of surface defects in ELTRAN wafers originate from particle on the porous silicon.

Effects of Defect Size on Crush Test Load of Butt Fusion Welded MDPE Pipes

  • Tun, Nwe Ni;Lai, Huan Sheng;Jeon, Gyu Min;Yoon, Kee Bong;Kil, Seong Hee
    • 에너지공학
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    • 제24권4호
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    • pp.55-62
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    • 2015
  • It is expected that the size of welding defect affects the mechanical performance of welded medium density polyethylene (MDPE) pipe joints. In this study, butt fusion welded MDPE pipe joints with a single spherical or planar defect of various sizes were studied using experimental crush testing and also by finite element method. The crush test showed that the mechanical performance of crush was not affected by the size and geometry of a single welding defect when the defect size was increased to 45% of the pipe's wall thickness. The simulation results indicated that the effect of the single welding defect on the Von Mises stress distribution near the defect explained the reason of the test results.

InSe 단일층의 vacancy 결함 특성 연구

  • 이서윤
    • EDISON SW 활용 경진대회 논문집
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    • 제6회(2017년)
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    • pp.468-472
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    • 2017
  • 2차원 InSe 단일층에 존재할 수 있는 vacancy defect인 In vacancy, Se vacancy의 원자구조 및 전자구조 특성을 제일원리계산을 이용해 살펴보았다. InSe $5{\times}5$ supercell을 이용하였으며 total energy를 구해 어떤 구조가 가장 안정한지 찾았다. Relax된 결함구조들을 clean InSe와 비교하여 어떤 변화가 있었는지 특징을 분석하였다. 이러한 intrinsic 결함들이 각각 어떤 구조로 relaxation되는지 살펴보고 clean InSe와 비교해보았다. 또한 각 결함구조의 density of states (DOS), projected density of states (PDOS)와 band structure를 clean InSe와 비교해봄으로써 defect state가 어떻게 나타나는지를 찾아보았다.

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AOI 데이터를 이용한 효과적인 Defect Size Distribution 구축방법: 반도체와 LCD생산 응용 (Effective Construction Method of Defect Size Distribution Using AOI Data: Application for Semiconductor and LCD Manufacturing)

  • 하정훈
    • 산업공학
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    • 제21권2호
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    • pp.151-160
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    • 2008
  • Defect size distribution is a probability density function for the defects that occur on wafers or glasses during semiconductor/LCD fabrication. It is one of the most important information to estimate manufacturing yield using well-known statistical estimation methods. The defects are detected by automatic optical inspection (AOI) facilities. However, the data that is provided from AOI is not accurate due to resolution of AOI and its defect detection mechanism. It causes distortion of defect size distribution and results in wrong estimation of the manufacturing yield. In this paper, I suggest a size conversion method and a maximum likelihood estimator to overcome the vague defect size information of AOI. The methods are verified by the Monte Carlo simulation that is constructed as similar as real situation.

마이크로 연소기에서 발생하는 열 소염과 화학 소염 현상 (II)- SiOx(x≤2) 플레이트의 물리, 화학적 성질이 소염에 미치는 영향 - (Thermal and Chemical Quenching Phenomena in a Microscale Combustor (II)- Effects of Physical and Chemical Properties of SiOx(x≤2) Plates on flame Quenching -)

  • 김규태;이대훈;권세진
    • 대한기계학회논문집B
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    • 제30권5호
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    • pp.405-412
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    • 2006
  • In order to realize a stably propagating flame in a narrow channel, flame instabilities resulting from flame-wall interaction should be avoided. In particular flame quenching is a significant issue in micro combustion devices; quenching is caused either by excessive heat loss or by active radical adsorptions at the wall. In this paper, the relative significance of thermal and chemical effects on flame quenching is examined by means of quenching distance measurement. Emphasis is placed on the effects of surface defect density on flame quenching. To investigate chemical quenching phenomenon, thermally grown silicon oxide plates with well-defined defect distribution were prepared. ion implantation technique was used to control defect density, i.e. the number of oxygen vacancies. It has been found that when the surface temperature is under $300^{\circ}C$, the quenching distance is decreased on account of reduced heat loss; as the surface temperature is increased over $300^{\circ}C$, however, quenching distance is increased despite reduced heat loss effect. Such abberant behavior is caused by heterogeneous surface reactions between active radicals and surface defects. The higher defect density, the larger quenching distance. This result means that chemical quenching is governed by radical adsorption that can be parameterized by oxygen vacancy density on the surface.

A Study on Proper Location of Welding Defect in Three Point Bend Testing with MDPE Pipe

  • Lai, Huan Sheng;Yoon, Kee Bong;Kil, Seong Hee
    • 에너지공학
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    • 제24권1호
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    • pp.1-9
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    • 2015
  • Welding defects affect the performance of welded pipe joints. In this study, a three point bend test of welded steel and medium density polyethylene (MDPE) pipe joints with defects of various defect locations and defect materials was studied using the finite element method. The defect was assumed to be located at 12 o'clock, 3 o'clock or 6 o'clock direction. The results showed that pipes failed more easily on the compression side due to stress or local buckling. The air defect was more dangerous than the steel defect if the defect was located in the compression side; otherwise, the defect material effect on the integrity of pipes was ignorable. It is argued that the integrity of pipes with defects in the compression side is weaker than that in other regions, and the defect should be located in the compression side or the 12 o'clock position in the three point bend test to maximize the effect of defect existence on the pipe structural integrity.

스퀴즈 병용 다이캐스팅법에 의한 Al-12%Si 합금의 결함제어에 관한 연구 (A study on Defect Control of Al-12%Si Alloy by Partial Squeeze Die Casting Method)

  • 김억수;김용현;이광학;김흥식
    • 한국주조공학회지
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    • 제15권4호
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    • pp.377-387
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    • 1995
  • Partial squeeze die casting is a special die casting process which combines squeeze technique to conventional die casting. The influence of squeeze pressure $(1500-3000kg/cm^2)$ and time-lags(0.5-2.0sec) on defect control, density and microstructure of ADC12 alloy die casts has been studied by appling partial squeeze die casting to air compressure front housing production. Defect free, maximum density of $2.736kg/cm^3$ with sound microstructure of ADC12 alloy die cast has been obtained by partial squeeze die casting technique at the pressure of $2000-2500kg/cm^2$ and time-lags of 1.0-2.0sec.

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공간적 확률 과정 기반의 수율 정보를 이용한 번인과 신뢰성 검사 정책 (Differential Burn-in and Reliability Screening Policy Using Yield Information Based on Spatial Stochastic Processes)

  • 황정윤;심영학
    • 산업경영시스템학회지
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    • 제35권4호
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    • pp.1-9
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    • 2012
  • Decisions on reliability screening rules and burn-in policies are determined based on the estimated reliability. The variability in a semiconductor manufacturing process does not only causes quality problems but it also makes reliability estimation more complicated. This study investigates the nonuniformity characteristics of integrated circuit reliability according to defect density distribution within a wafer and between wafers then develops optimal burn-in policy based on the estimated reliability. New reliability estimation model based on yield information is developed using a spatial stochastic process. Spatial defect density variation is reflected in the reliability estimation, and the defect densities of each die location are considered as input variables of the burn-in optimization. Reliability screening and optimal burn-in policy subject to the burn-in cost minimization is examined, and numerical experiments are conducted.

6H-SiC wafer의 결정성 및 전기적 특성 (Crystallinity and electrical properties of 6H-SiC wafers)

  • 김화목;임창성;오근호
    • 한국결정성장학회지
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    • 제7권3호
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    • pp.393-399
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    • 1997
  • 승화법에 의한 6H-SiC 단결정의 최적 성장조건을 설정하여 고품질의 6H-Sic 단결정을 성장하였다. 성장된 결정의 직경은 약 33 mm, 길이는 약 11 mm였다. 성장된 결정을 절단하여 연마한 후 광학현미경을 이용하여 연마된 SiC wafer의 micropipe density와 planar defect density를 측정한 결과, micropipe density는 400개/$ \textrm{cm}^2$이었고 planar defect density는 50개/$\textrm{cm}^2$이었다. 이 6H-SiC wafer와 기판으로 사용된 Acheson 결정의 결정성을 비교하기 위하여 Raman 분광법과 double crystal X-ray diffraction 분석법이 사용되었다. 이 분석에 의해 승화법에 의해 성장된 6H-SiC wafer가 Acheson seed보다 결정성이 우수하였다. Hall effect 측정법에 의해 불순물이 첨가되지 않은 6H-SiC wafer의 전기적인 특성을 측정하였으며 그 결과 캐리어 농도는 $3.91{\times}10^{15}/\textrm {cm}^3$이었고, n-type이었다.

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Defect에 의한 다이오드 reverse recovery특성시의 전류 증가현상 (Current increase resulted from defect during diode reverse recovery)

  • 이준호;이호성;박준;조중열
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 하계학술대회 논문집 F
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    • pp.2572-2574
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    • 1999
  • 본논문은 제작된 다이오드 switching시 나타난 전류 증가현상을 관측하고 그 원인을 분석했다. 증가현상을 보이는 구조는 다이오드에 전자를 조사한 소자로 proton을 조사한 구조에 비해서 접합부근에 high defect density 영역이 형성된다. Reverse recovery시에 이영역에 높은 역방향 전계가 형성, 조사에 순간적으로 전류가 증가하게 한다.

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