• Title, Summary, Keyword: Carrier-Grade

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Evaluation of mechanical backside damage by minority carrier recombination lifetime and photo-acoustic displacement method in silicon wafer (실리콘 웨이퍼에서 광열 변위법과 소수 반송자 재결합 수명 측정에 의한 기계적 후면 손상 평가)

  • 최치영;조상희
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.1
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    • pp.117-123
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    • 1998
  • We investigated the effect of mechanical backside damage in Czochralski grown silicon wafer. The intensity of mechanical damage was evaluated by minority carrier recombination lifetime by laser excitation/microwave reflection photoconductivity decay method, photo-acoustic displacement method, X-ray section topography, and wet oxidation/preferential etching methods. The data indicate that the higher the mechanical damage intensity, the lower the minority carrier lifetime, and the photo-acoustic displacement values increased proportionally, and it was at Grade 1: Grade 2:Grade 3 = 1:19.6:41 that the normalized relative quantization ratio of excess photo-acoustic displacement in damaged wafer was calculated, which are normalized to the excess PAD from sample Grade 1.

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Relative quantitative evaluation of mechanical damage layer by X-ray diffuse scattering in silicon wafer surface (실리콘 웨이퍼 표면에서 X-선 산만산란에 의한 기계적 손상층의 상대 정량 평가)

  • 최치영;조상희
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.4
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    • pp.581-586
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    • 1998
  • We investigated the effect of mechanical back side damage in Czochralski grown silicon wafer. The intensity of mechanical damage was evaluated by minority carrier recombination lifetime by laser excitation/microwave reflection photoconductivity decay method, degree of X-ray diffuse scattering, X-ray section topography, and wet oxidation/preferential etching methods. The data indicate that the higher the mechanical damage intensity, the lower the minority carrier lifetime, and the magnitude of diffuse scattering and X-ray excess intensity increased proportionally, and it was at Grade 1:Grade 2:Grade 3=1:7:18.4 that the normalized relative quantization ratio of excess intensity in damaged wafer was calculated, which are normalized to the excess intensity from sample Grade 1.

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Characterization of carrier transport and trapping in semiconductor films during plasma processing

  • Nunomura, Shota;Sakata, Isao;Matsubara, Koji
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.391-391
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    • 2016
  • The carrier transport is a key factor that determines the device performances of semiconductor devices such as solar cells and transistors [1]. Particularly, devices composed of in amorphous semiconductors, the transport is often restricted by carrier trapping, associated with various defects. So far, the trapping has been studied for as-grown films at room temperature; however it has not been studied during growth under plasma processing. Here, we demonstrate the detection of trapped carriers in hydrogenated amorphous silicon (a-Si:H) films during plasma processing, and discuss the carrier trapping and defect kinetics. Using an optically pump-probe technique, we detected the trapped carriers (electrons) in an a-Si:H films during growth by a hydrogen diluted silane discharge [2]. A device-grade intrinsic a-Si:H film growing on a glass substrate was illuminated with pump and probe light. The pump induced the photocurrent, whereas the pulsed probe induced an increment in the photocurrent. The photocurrent and its increment were separately measured using a lock-in technique. Because the increment in the photocurrent originates from emission of trapped carriers, and therefore the trapped carrier density was determined from this increment under the assumption of carrier generation and recombination dynamics [2]. We found that the trapped carrier density in device grade intrinsic a-Si:H was the order of 1e17 to 1e18 cm-3. It was highly dependent on the growth conditions, particularly on the growth temperature. At 473K, the trapped carrier density was minimized. Interestingly, the detected trapped carriers were homogeneously distributed in the direction of film growth, and they were decreased once the film growth was terminated by turning off the discharge.

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Evaluation of Health Status of College Students by Cornell Medical Index : In Conjunction with their Academic Grade (CMI에 의(依)한 일부(一部) 남여(男女) 대학생(大學生)들의 건강실태(健康實態)의 평가(評價)와 학업성적(學業成績)과의 관계(關係))

  • Joo, Duck-Won;Chung, Kyou-Chull
    • Journal of Preventive Medicine and Public Health
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    • v.10 no.1
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    • pp.52-58
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    • 1977
  • By evaluating the health status by Cornell Medical Index in conjunction with their academic grade, we attempted to find out whether any health condition may affect on their academic carrier. CMI health questionnaire was filled out by student and matched with one's own academic score if the previous year. Academic score was classified into 5 grades: excellent, very good, good, fair and poor. Difference in number of questions between sections was corrected by standard score method with means of 50 and standard deviation of 10. Differences in number of 'yes' answers between sections and between groups of students in each grade were statistically tested by two-way variance analysis method. On the other hand, influence of neuropsychiatric factors (section M-R) on the academic carrier was analyzed by $X^2-test$ with Fukamachi's classification. The following were the results obtained in this study: 1) Number of 'yes' answers in sections related to mood and feeling patterns (sections M-R) were appeared to be influential to academic carrier in male students, but not in female students. 2) Generally speaking, in groups of higher academic grade, number of 'yes' answers in each section was on an averege 50 or less, and in groups of lower academic grade, the number was 50 or more depending on sections. 3) Number of 'yes' answers between sections and between groups in each academic grade were significantly different both in male and female college students. 4) It was noteworthy that data obtained from CMI questionnaire might be variable subjectively by examinees with some factors at the time of administration.

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Design and Implementation of Carrier-Grade Network Address Translation (NAT) (캐리어 급 주소 변환기(NAT)의 설계 및 구현)

  • Lee, Moon-Sang;Lee, Chiyoung;Kim, Wootae;Lee, Young-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.10
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    • pp.1290-1300
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    • 2016
  • Recently, various middle box services have been developed and applied to provide network functions to end nodes of the network. Especially, network virtualization is increasingly proceeding by applying the virtualization technologies of cloud computing field to network field, and network platforms for various flexible services are being developed to connect among the virtual network devices. Carrier-grade Network Address Translation (CGNAT) is also one of these flexible network services. This paper designs and implements the DPDK-based CGNAT framework that provides flexibility and maximizes address translation throughput. Our framework achieves 15.5 times higher throughput than the address translation service by Linux kernel.

Temperature Distribution for a Membrane type LNGC Cargo Tank (멤브레인형 LNG선의 화물창 온도분포 해석)

  • Heo, Joo Ho;Jeon, Yoon Ho
    • Journal of the Society of Naval Architects of Korea
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    • v.34 no.4
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    • pp.108-118
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    • 1997
  • For the LNG carrier, the calculation of temperature distribution of cargo tank is necessary to select the steel grade and to estimate the boil-off rate(BOR). Since the previous studies with 2-D and 3-D method ignored the effect of several primary members, the effect was included by applying the better equations for the convection coefficient that is the most important item in this kind of study. After evaluating the program considering the primary members, the results are reflected to the design of the concerned LNG carrier.

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A Simple Carrier Frequency Recovery Scheme for DVB-S2 Systems (DVB-S2 시스템을 위한 간단한 반송파 주파수 복구부 설계에 관한 연구)

  • Oh, Jong-Kyu;Yoon, Eun-Chul;Kim, Joon-Tae
    • Journal of Broadcast Engineering
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    • v.15 no.2
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    • pp.182-191
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    • 2010
  • In this paper, a simple Carrier Frequency Recovery(CFR) scheme is introduced. In relating the use of consumer-grade equipment and satellite transmission environments, carrier frequency recovery have to recovery a large initial Carrier Frequency Offset(CFO), which is 20% normalized CFO, for DVB-S2 receivers. For these reasons, conventional CFR schemes for DVB-S2 systems need significant hardware complexity. Introduced CFR scheme employs Fitz algorithm for coarse CFR and recovers a coarse CFO accurately, and a simple pilot block correlation algorithm is employed for fine CFR. Introduced scheme reduce the number of multiplication operations by 80% and does not need any additional memory without degrading the achievable performance.

Flush Optimizations to Guarantee Less Transient Traffic in Ethernet Ring Protection

  • Lee, Kwang-Koog;Ryoo, Jeong-Dong
    • ETRI Journal
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    • v.32 no.2
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    • pp.184-194
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    • 2010
  • Ethernet ring protection (ERP) technology, which is defined in ITU-T Recommendation G.8032, has been developed to provide carrier grade recovery for Ethernet ring networks. However, the filtering database (FDB) flush method adopted in the current ERP standard has the drawback of introducing a large amount of transient traffic overshoot caused by flooded Ethernet frames right after protection switching. This traffic overshooting is especially critical when a ring provides services to a large number of clients. According to our experimental results, the traditional FDB flush requires a link capacity about sixteen times greater than the steady state traffic bandwidth. This paper introduces four flush optimization schemes to resolve this issue and investigates how the proposed schemes deal with the transient traffic overshoot on a multi-ring network under failure conditions. With a network simulator, we evaluate the performance of the proposed schemes and compare them to the conventional FDB flush scheme. Among the proposed methods, the extended FDB advertisement method shows the fastest and most stable protection switching performance.

Faultless Protection Methods in Self-Healing Ethernet Ring Networks

  • Lee, Kwang-Koog;Ryoo, Jeong-Dong;Joo, Bheom Soon
    • ETRI Journal
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    • v.34 no.6
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    • pp.816-826
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    • 2012
  • Self-healing Ethernet rings show promise for realizing the SONET/SDH-grade resilience in Carrier Ethernet infrastructures. However, when a ring is faulty, high-priority protection messages are processed in less time than low-priority data frames are processed. In this situation, any delayed data frames either being queued or traveling through long ring spans will cause the ring nodes to generate incorrect forwarding information. As a result, the data frames spread in the wrong direction, causing the ring to become unstable. To solve this problem, we propose four schemes, that is, dual flush, flush delay timer setting, purge triggering, and priority setting, and evaluate their protection performance under various traffic conditions on a ring based on the Ethernet ring protection (ERP) method. In addition, we develop an absorbing Markov chain model of the ERP protocol to observe how traffic congestion can impact the protection performance of the proposed priority setting scheme. Based on our observations, we propose a more reliable priority setting scheme, which guarantees faultless protection, even in a congested ring.

Crystal Growth and Characterization of Metallurgical-grade Polycrystalline Silicon by the Bridgman Method (Bridgman법에 의한 금속급 다결정 Si의 결정성장 및 특성평가에 관한 연구)

  • Lee, Chang-Won;Kim, Kye-Soo;Hong, Chun-Pyo
    • Journal of Korea Foundry Society
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    • v.14 no.1
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    • pp.28-34
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    • 1994
  • Metallurgical-grade polycrystalline silicon was directionally solidified at growth rates of $0.2{\sim}1.0mm/min$ by using split type, reusable graphite molds which were coated with $Si_3N_4$ powder. The resultant grain sizes of the silicon ingots and the shapes of the solid/liquid(S/L) interfaces were investigated. X-ray diffraction was used to determine the preferred orientation in each of the silicon ingots. The impurity content of the silicon was analyzed and the resistivities of the ingots were measured. During the growth of an ingot, the shape of the S/L interface was concave to the silicon melt, and the resistivity decreased. The presence of Al which can be acting as a carrier, is thought to be the main factor causing such a decrease in resistivity. When a growth rate of 0.2㎜/min was used, the preferred orientation was found to be (111).

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