• 제목/요약/키워드: Positive fixed charge

검색결과 8건 처리시간 0.028초

Nano CMOSFET에서 Channel Stress가 소자에 미치는 영향 분석 (Characterization of the Dependence of the Device on the Channel Stress for Nano-scale CMOSFETs)

  • 한인식;지희환;김경민;주한수;박성형;김용구;왕진석;이희덕
    • 대한전자공학회논문지SD
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    • 제43권3호
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    • pp.1-8
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    • 2006
  • 본 논문에서는 채널 stress에 따른 Nano-scale CMOSFET의 소자 및 신뢰성 (HCI, NBTI)특성을 분석하였다. 잘 알려져 있듯이 NMOS는 tensile, PMOS는 compressive stress가 인가된 경우에 소자의 특성이 개선되었으며, 이는 전자와 정공의 이동도 증가에 의한 것임을 확인하였다. 그러나 신뢰성인 경우에는 소자 특성과는 다른 특성을 나타냈는데, NMOS와 PMOS 모두 tensile stress가 인가된 경우에 hot carrier 특성이 더 열화 되었으며, PMOS의 PBTI 특성도 tensile에서 더 열화 되었음을 확인하였다. 신뢰성을 분석한 결과, 채널의 tensile stress로 인하여 $Si/SiO_2$ 계면에서 interface trap charge의 생성과 산화막 내 positive fixed charge의 생성에 많은 영향을 끼침을 알 수 있었다. 그러므로 나노급 CMOSFET에 적용되는 strained-silicon MOSFET의 개발을 위해서는 소자의 성능 뿐 만 아니라 신뢰성 또한 고려되어야 한다.

SiC 열산화막의 Electrode형성조건에 따른 C-V특성 변화 (The variation of C-V characteristics of thermal oxide grown on SiC wafer with the electrode formation condition)

  • 강민정;방욱;송근호;김남균;김상철;서길수;김형우;김은동
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 하계학술대회 논문집
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    • pp.354-357
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    • 2002
  • Thermally grown gate oxide on 4H-SiC wafer was investigated. The oxide layers were grown at l150$^{\circ}C$ varying the carrier gas and post activation annealing conditions. Capacitance-Voltage(C-V) characteristic curves were obtained and compared using various gate electrode such as Al, Ni and poly-Si. The interface trap density can be reduced by using post oxidation annealing process in Ar atmosphere. All of the samples which were not performed a post oxidation annealing process show negative oxide effective charge. The negative oxide effective charges may come from oxygen radical. After the post oxidation annealing, the oxygen radicals fixed and the effective oxide charge become positive. The effective oxide charge is negative even in the annealed sample when we use poly silicon gate. Poly silicon layer was dope by POCl$_3$ process. The oxide layer may be affected by P ions in poly silicon layer due to the high temperature of the POCl$_3$ doping process.

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표면전축적층을 이용한 HLE 채양전지의 효율개선에 관한 연구 (A Study on the Efficiency Improvement of HLE Solar Cell Using Surface Charge Accumulated Layer)

  • 장지근;김봉렬
    • 대한전자공학회논문지
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    • 제22권4호
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    • pp.92-100
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    • 1985
  • P형 Si기판에 N에피층을 성장시키고 Si-AR막 계면에서 고정양전하밀도(Qss)를 높임으로써 전지의 에미터 표면영역을 N'전하축적층으로 나타낸 새로운 형태의 N'N/P HLE 태':1전지 를 제 작하였다. 제작된 전지의 종류로는 AR막으로 SiOr층을 이용한 OCI전지와 Si,N,/sioxynitride층을 이응한 NCI전지로 구분하였다. 전지의 AR막내 Qss분포는 커패시턴스-전압 측정을 통해 조사하였으며 이로부터 NCI전 al (Qss=1.79~ 1.84$\times$1011cm-2) 가 OCI전 지 (Qss=3.03~ 4.40$\times$1011cm-1) 에 비 해 로면 전 하축 적 층 이 효과적 으로 나타남을 알 수 있었다. JCR할로겐 램프로 100mW/cm2의 인공조명을 만들어 효율특성을 분석한 결과 유효수광면적에 대한 평균(최대)변환효율이 OCI전지에서 15.18(15.46)%, NCI전지에서 16.31(17.07%)로 나타났다.

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회원제 도매클럽의 연회비부과에 대한 이론적 연구 (Theoretical Analysis on Membership Fee of Wholesale Club)

  • 김상훈
    • 한국유통학회지:유통연구
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    • 제5권2호
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    • pp.91-105
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    • 2001
  • Wholesale club is one of the fastest expanding retailer formats. Given its key features such as limited assortment and no promotion policy, the current paper provides a theory on why the wholesale clubs charge their members fixed annual fees. In a competitive setting with supermarkets, the proposed model demonstrates that the membership fee is the optimal reaction of wholesale clubs to supermarkets" sales promotion. More specifically, the positive amount of annual fee is only justified under the condition that there exists consumer heterogeneity in consumption rate and when the supermarket exercises price promotion on the product that the wholesale club carries. This paper describes the competition in a stylized fashion and derives the optimal membership fee under a scenario where retail promotion is present. This study is valuable in that it offers a different explanation on wholesale club membership fee than conventional wisdoms such as cost sharing and that it provides insights to the managers who consider no-fee format.

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Effect of Stimulus Waveform of Biphasic Current Pulse on Retinal Ganglion Cell Responses in Retinal Degeneration (rd1) mice

  • Ahn, Kun No;Ahn, Jeong Yeol;Kim, Jae-Hyung;Cho, Kyoungrok;Koo, Kyo-In;Senok, Solomon S.;Goo, Yong Sook
    • The Korean Journal of Physiology and Pharmacology
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    • 제19권2호
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    • pp.167-175
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    • 2015
  • A retinal prosthesis is being developed for the restoration of vision in patients with retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Determining optimal electrical stimulation parameters for the prosthesis is one of the most important elements for the development of a viable retinal prosthesis. Here, we investigated the effects of different charge-balanced biphasic pulses with regard to their effectiveness in evoking retinal ganglion cell (RGC) responses. Retinal degeneration (rd1) mice were used (n=17). From the ex-vivo retinal preparation, retinal patches were placed ganglion cell layer down onto an $8{\times}8$ multielectrode array (MEA) and RGC responses were recorded while applying electrical stimuli. For asymmetric pulses, 1st phase of the pulse is the same with symmetric pulse but the amplitude of 2nd phase of the pulse is less than $10{\mu}A$ and charge balanced condition is satisfied by lengthening the duration of the pulse. For intensities (or duration) modulation, duration (or amplitude) of the pulse was fixed to $500{\mu}s$($30{\mu}A$), changing the intensities (or duration) from 2 to $60{\mu}A$(60 to $1000{\mu}s$). RGCs were classified as response-positive when PSTH showed multiple (3~4) peaks within 400 ms post stimulus and the number of spikes was at least 30% more than that for the immediate pre-stimulus 400 ms period. RGC responses were well modulated both with anodic and cathodic phase-1st biphasic pulses. Cathodic phase-1st pulses produced significantly better modulation of RGC activity than anodic phase-1st pulses regardless of symmetry of the pulse.

한국프로축구팀의 감독교체가 팀 경기성과에 미치는 영향 (The Effects of Coach Turnover and Sport Team Performance: Evidence from the Korean Professional Soccer League 1983-2013)

  • 김필수;김대권
    • 한국체육학회지인문사회과학편
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    • 제54권4호
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    • pp.329-345
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    • 2015
  • 본 연구는 한국프로축구팀 감독교체가 팀 경기성과에 미치는 효과를 경영학의 조직학습이론을 적용하여 규명하고자 하였다. 1983년 시즌부터 2013년 시즌까지 30년 동안의 19개 팀과 96명의 감독에 대한 307개의 팀-연도 데이터를 기반으로 패널데이터를 구성하였고, 최종적으로 226개의 팀 데이터가 실증분석에 투입되었다. 자동상관 및 이분산성의 문제를 해결하기 위하여 고정효과 일반화최소자승법(Fixed Effect Generalized Least Square Regression)을 사용하여 분석하였으며 연구결과는 다음과 같다. 첫째, 감독교체는 팀 경기성과와 부(-)의 관계를 가지는 것으로 나타났다. 둘째, 시즌기간(on-season)의 감독교체는 팀 경기성과에 부정적인 영향을 미치는 것으로 나타났다. 시즌기간에 감독을 교체하는 경우 악순환이론 관점이 적용되는 것으로 확인되었다. 셋째, 비시즌기간(off-season)의 감독교체는 팀 경기성과에 긍정적인 영향을 미치는 것으로 나타났다. 비시즌기간에 지도자를 교체하는 경우 상식이론 관점이 적용되는 것으로 확인되었다. 넷째, 시즌기간의 감독교체와 비시즌기간의 감독교체 간의 팀 경기성과의 차이를 비교한 결과, 비시즌기간의 감독교체가 시즌기간의 감독교체에 비해 유의한 팀 경기성과를 보였다. 다섯째, 감독교체가 발생한 경우 후임감독으로 내부출신을 선호하는 것으로 나타났다. 여섯째, 내부출신감독은 팀 경기성과에 부정적인 영향을 미치는 것으로 나타났다. 일곱째, 감독교체와 팀 경기성과 간의 부(-)의 관계 사이에는 내부출신감독요인이 매개 역할을 하는 것으로 나타났다. 본 연구는 프로축구산업 현장에서 팀 경기성과의 향상을 위한 감독교체가 필요할 때 후임 감독이 역량을 효과적으로 발휘할 수 있는 교체시기에 대한 시사점을 제공한다.

Influence of the hydrogen post-annealing on the electrical properties of metal/alumina/silicon-nitride/silicon-oxide/silicon capacitors for flash memories

  • Kim, Hee-Dong;An, Ho-Myoung;Seo, Yu-Jeong;Zhang, Yong-Jie;Kim, Tae-Geun
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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    • pp.122-122
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    • 2008
  • Recently, Metal/Alumina/Silicon-Nitride/Silicon-Oxide/Silicon (MANOS) structures are one of the most attractive candidates to realize vertical scaling of high-density NAND flash memory [1]. However, as ANO layers are miniaturized, negative and positive bias temperature instability (NBTI/PBTI), such as the flat band voltage shift, ${\Delta}V_{FB}$, the interfacial trap density increase, ${\Delta}D_{it}$, the gate leakage current, ${\Delta}I_G$. and the retention characteristics, in MONOS capacitors, becomes an important issue in terms of reliability. It is well known that tunnel oxide degradation is a result of the oxide and interfacial traps generation during FN (Fowler-Nordheim) stress [2]. Because the bias temperature stress causes an increase of both interfacial-traps and fixed oxide charge could be a factor, witch can degrade device reliability during the program and erase operation. However, few studies on NBTI/PBTI have been conducted on improving the reliability of MONOS devices. In this work, we investigate the effect of post-annealing gas on bias temperature instability (BTI), such as the flat band voltage shift, ${\Delta}V_{FB}$, the interfacial trap density shift, ${\Delta}I_G$ retention characteristics, and the gate leakage current characteristics of MANOS capacitors. MANOS samples annealed at $950^{\circ}C$ for 30 s by a rapid thermal process were treated via additional annealing in a furnace, using annealing gases $N_2$ and $N_2-H_2$ (2 % hydrogen and 98 % nitrogen mixture gases) at $450^{\circ}C$ for 30 min. MANOS samples annealed in $N_2-H_2$ ambient had the lowest flat band voltage shift, ${\Delta}V_{FB}$ = 1.09/0.63 V at the program/erase state, and the good retention characteristics, 123/84 mV/decade at the program/erase state more than the sample annealed at $N_2$ ambient.

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가정간호 사업에 대한 의사, 간호사, 진료관련부서 직원 및 환자의 인식 비교 (A Study on Differences of Opinions on Home Health Care Program among Physicians, Nurses, Non-medical personnel, and Patients.)

  • 김용순;임영신;전춘영;이정자;박지원
    • 대한간호
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    • 제29권2호
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    • pp.48-65
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    • 1990
  • The government has adopted a policy to introduce Home Health Care Program, and has established a three stage plan to implement it. The three stage plan is : First, to amend Article 54 (Nurses for Different Types of Services) of the Regulations for Implementing the Law of Medical Services; Second, to tryout the new system through pilot projects established in public hospitals and clinics; and third, to implement at all hospitals and equivalent medical institutions. In accordance with the plan, the Regulation has been amend and it was promulgated on January 9,1990, thus establishing a legal ground for implementing the policy. Subsequently, however, the Medical Association raised its objection to the policy, causing a delay in moving into the second stage of the plan. Under these circumstances, a study was conducted by collecting and evaluating the opinions of physicians, nurses, non-medical personnel and patients on the need and expected result from the home health care for the purpose of help facilitating the implementation of the new system. As a result of this study, it was revealed that: 1. Except the physicians, absolute majority of all other three groups - nurses, non-medical personnel and patients -gave positive answers to all 11 items related to the need for establishing a program for Home Health Care. Among the physicians, the opinions on the need for the new services were different depending on their field of specialty, and those who have been treating long term patients were more positive in supporting the new system. 2. The respondents in all four groups held very positive view for the effectiveness and the expected result of the program. The composite total of scores for all of 17 items, however, re-veals that the physicians were least positive for the- effectiveness of the new system. The people in all four groups held high expectation on the system on the ground that: it will help continued medical care after the discharge from hospitals; that it will alleviate physical and economic burden of patient's family; that it will offer nursing services at home for the patients who are suffering from chronic disease, for those early discharge from hospital, or those who are without family members to look after the patients at home. 3. Opinions were different between patients( who will receive services) and nurses (who will provide services) on the types of services home visiting nurses should offer. The patients wanted "education on how to take care patients at home", "making arrangement to be admitted into hospital when need arises", "IV injection", "checking blood pressure", and "administering medications." On the other hand, nurses believed that they can offer all 16 types of services except "Controlling pain of patients", 4. For the question of "what types of patients are suitable for Home Health Care Program; " the physicians, the nurses and non-medical personnel all gave high score on the cases of "patients of chronic disease", "patients of old age", "terminal cases", and the "patients who require long-term stay in hospital". 5. On the question of who should control Home Health Care Program, only physicians proposed that it should be done through hospitals, while remaining three groups recommended that it should be done through public institutions such as public health center. 6. On the question of home health care fee, the respondents in all four groups believed that the most desireable way is to charge a fixed amount of visiting fee plus treatment service fee and cost of material. 7. In the case when the Home Health Care Program is to be operated through hospitals, it is recommended that a new section be created in the out-patient department for an exclusive handling of the services, instead of assigning it to an existing section. 8. For the qualification of the nurses for-home visiting, the majority of respondents recommended that they should be "registered nurses who have had clinical experiences and who have attended training courses for home health care". 9. On the question of if the program should be implemented; 74.0% of physicians, 87.5% of non-medical personnel, and 93.0% of nurses surveyed expressed positive support. 10. Among the respondents, 74.5% of -physicians, 81.3% of non-medical personnel and 90.9% of nurses said that they would refer patients' to home health care. 11. To the question addressed to patients if they would take advantage of home health care; 82.7% said they would if the fee is applicable to the Health Insurance, and 86.9% said they would follow advises of physicians in case they were decided for early discharge from hospitals. 12. While 93.5% of nurses surveyed had heard about the Home Health Care Program, only 38.6% of physicians surveyed, 50.9% of non-medical personnel, and 35.7% of patients surveyed had heard about the program. In view of above findings, the following measures are deemed prerequisite for an effective implementation of Home Health Care Program. 1. The fee for home health care to be included in the public health insurance. 2. Clearly define the types and scope of services to be offered in the Home Health Care Program. 3. Develop special programs for training nurses who will be assigned to the Home Health Care Program. 4. Train those nurses by consigning them at hospitals and educational institutions. 5. Government conducts publicity campaign toward the public and the hospitals so that the hospitals support the program and patients take advantage of them. 6. Systematic and effective publicity and educational programs for home heath care must be developed and exercises for the people of medical professions in hospitals as well as patients and their families. 7. Establish and operate pilot projects for home health care, to evaluate and refine their programs.

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