• Title/Summary/Keyword: Ecr

Search Result 286, Processing Time 0.032 seconds

EPICS를 이용한 ECR 이온원 운전 제어 시스템 구성 방안

  • Jang, Dae-Sik;Jin, Jeong-Tae;O, Byeong-Hun;Kim, Min-Seok
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2011.02a
    • /
    • pp.237-237
    • /
    • 2011
  • 다가 이온원 제조를 위한 ECR 이온원 제작과 더불어 이를 효과적으로 운전 제어할 수 있는 방안을 만들어야 한다. 이 운전 제어 방안은 두 가지 기능을 만족할 수 있도록 구성해야 하는데, 초기 실험실에서 ECR 이온원의 성능 검증을 하기에 유리하도록 알고리즘이나 시퀀스를 보다 용이하게 변경할 수 있도록 만들고 이후 확정된 알고리즘과 시퀀스를 이용하여 이온원의 안전을 보장하면서 최소한의 운전자만으로도 운전 가능하도록 구성해야 한다. 이를 구현하기 위해서 ECR 이온원 운전 제어와 관계된 모든 부대 장치들을 EPICS (Experimental Physics and Industrial Control System)로 운전하고 제어할 수 있도록 통합하면서 알고리즘의 복잡함으로 인해 발생할 수 있는 불확실성을 줄이기 위해 부대 장치를 구성하는 개별 장치 단위로 알고리즘을 만들어 EPICS database로 구현하고 운전 및 장치 보호를 위해 필요한 시퀀스는 EPICS sequencer를 이용하여 구현하였다. 현재까지 ECR 플라즈마 생성, 빔인출 그리고 입자 진단을 위해 사용된 전원 장치들을 운전 제어하기 위해 구현된 내용을 소개하고 이를 바탕으로 개별 장치에 확대하여 적용할 수 있는 방안에 대하여 연구하였다.

  • PDF

An Investigation of Selective Etching of GaAs to Al\ulcornerGa\ulcornerAs Using BCI$_3$SF\ulcorner Gas Mixture in ECR Plasma (ECR 플라즈마에서 $BCI_3/SF_6$ 혼합 가스를 이용한 $Al_{0.25}Ga_{0.75}As$에 대한 GaAs의 선택적 식각에 대한 연구)

  • 이철욱;이동율;손정식;배인호;박성배
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.11 no.6
    • /
    • pp.447-452
    • /
    • 1998
  • The selective dry etching of GaAs to Al\ulcornerGa\ulcornerAs using $BCI_3/SF_6$ gas mixture in electron cyclotron resonance(ECR) plasma is investigated. A selectivity of GaAs to AlGaAs of more than 100 and maximum etch rate of GaAs are obtained at a gas ratio $SF_6/BCI_3+SF_6$ of 25%. We verified the formation of $AlF_3$ on $Al_{0.25}Ga_{0.75}As$from the Auger spectra which enhanced the etch selectivity. In order to investigate surface damage of AlGaAs caused by ECR plasma, we performed a low temperature photoluminescence(PL) measurement as a function of RF power. As the RF power. As the RF power increases, the PL intensity decreases monotonically from 50 to 100 Wand then repidly decreases until 250 W. This behavior is due to surface damage by plasma treatment. This dry etching technique using $BCI_3/SF_6$ gas mixture in ECR plasma is suitable for gate recess formation on the GaAs based pseudomorphic high electron mobility transistor(PHEMT)

  • PDF

Low Temperature Thermal Oxidation using ECR Oxygen Plasma (ECR 산소 플라즈마를 이용한 저온 열산화)

  • 이정열;강석원;이진우;한철희;김충기
    • Journal of the Korean Institute of Telematics and Electronics A
    • /
    • v.32A no.3
    • /
    • pp.68-77
    • /
    • 1995
  • Characteristics of electron cyclotron resonance (ECR) plasma thermal oxide grown at low-temperature have been investigated. The effects of several process parameters such as substrate temperature, microwave power, gas flow rate, and process pressure on the growth rate of the oxide have been also investigated. It was found that the plasma density, reactive ion species, is strongly related to the growth rate of ECR plasma oxied. It was also found that the plasma density increases with microwave power while it decreases with decreasing O2 flow rate. The oxidation time dependence of the oxide thichness showed parabolic characteristics. Considering ECR plasma thermal oxidation at low-temperature, the linear as well as parabolic rate constants calculated from fitting data by using the Deal-Grove model was very large in comparison with conventional thermal oxidation. The ECR plasma oxide grown on (100) crystalline-Si wafer exhibited good electrical characteristics which are comparable to those of thermal oxide: fixed oxide charge(N$_{ff}$)= 7${\times}10^{10}cm^{-2}$, interface state density(N$_{it}$)=4${\times}10^[10}cm^{-2}eV^{-1}$, and breakdown field > 8MV/cm.

  • PDF

Characteristics of copper/C films on PET substrate prepared by ECR-MOCVD at room temperature (상온 ECR-MOCVD에 의해 제조되는 Cu/C박막특성)

  • Lee, Joong-Kee;Jeon, Bup-Ju;Hyun, Jin;Byun, Dong-Jin
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.6 no.3
    • /
    • pp.44-53
    • /
    • 2003
  • Cu/C films were prepared at room temperature under $Cu(hfac)_2-Ar-H_2$ atmosphere in order to obtain metallized polymer by using ECR-MOCVD(Electron Cyclotron Resonance Metal Organic Chemical Vapor Deposition) coupled with a DC bias system. The room temperature MOCVD on polymer substrate could be possible by collaboration of ECR and a DC bias. Structural analysis of the films by ECR was found that fine copper grains embedded in an amorphous polymer matrix with indistinctive interfacial layer. The increase in $H_2$ contents brought on copper-rich film formation with low electric resistance. On the other hand carbon-rich films with low sheet electric resistance were prepared in argon atmosphere. The electric sheet resistance of Cu/C films with good interfacial property were controlled at $10^8$~$10^0$ Ohm/sq. ranges by the $H_2$/Ar mole ratio and the shielding effectiveness of the film showed maximum up to 45dB in the our experimental range.

EGR Effects on Exhaust Gas of Heavy-Duty Turbo Charge Engine with Low Pressure Route System (저압방식을 적용한 대형과급기관의 배기가스에 관한 EGR효과)

  • 오용석
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.3 no.1
    • /
    • pp.58-62
    • /
    • 2002
  • The efforts of EGR on performance and emissions were investigated in this study. The engine used for the tests was a six-cylinder, 11 liter, and turbo-charged, heavy-duty diesel engine with a low pressure route ECR system. The volume of recirculated gas was controlled by a manually operated valve which was installed between the turbine outlet and compressor inlet. The experiments were performed at various engine speeds and loads while the ECR rates were set at 4% and 8%. Exhaust emissions with EGR system were compared with the baseline emissions.

  • PDF

Optical properties of diamond-like carbon films deposited by ECR-PECVD method (ECR-PECVD 방법으로 증착한 Diamond-Like carbon 박막의 광 특성)

  • Kim, Dae-Nyoun;Kim, Ki-Hong;Kim, Hye-Dong
    • Journal of Korean Ophthalmic Optics Society
    • /
    • v.9 no.2
    • /
    • pp.291-299
    • /
    • 2004
  • DLC films were deposited using the ECR-PECVD method with the fixed deposition condition, such as ECR power, methane and hydrogen gas-flow rates and deposition time, for various substrate bias voltage. We have investigated the ion bombardment effect induced by the substrate bias voltage on films during the deposition of film. The characteristic of the films were analyzed using the FTIR, Raman, and UV/Vis spectroscopy analysis shows that the amount of dehydrogenation in films was increased with the increase of substrate bias voltage and films thickness was decreased. Raman scattering analysis shows that integrated intensity ratio(ID/IG) of the D and G peak was increased as the substrate bias voltage increased and films hardness was increased. Optical transmittances of DLC film were decreased with increasing deposition time and substrate bias voltage. From these results, it can be concluded that films deposited at this experimental have the enhanced characteristics of DLC because of the ion bombardment effect on films during the deposition of film.

  • PDF

The prevalence and characteristics of external cervical resorption based on cone-beam computed tomographic imaging: a cross-sectional study

  • Matheus Diniz Ferreira;Matheus Barros-Costa;Felipe Ferreira Costa;Deborah Queiroz Freitas
    • Restorative Dentistry and Endodontics
    • /
    • v.47 no.4
    • /
    • pp.39.1-39.12
    • /
    • 2022
  • Objectives: This study investigated the prevalence and characteristics of external cervical resorption (ECR) regarding sex, age, tooth, stages of progression, and portal of entry, using cone-beam computed tomography (CBCT) scans. Materials and Methods: CBCT scans of 1,313 patients from a Brazilian subpopulation comprising 883 female and 430 male patients (mean age, 55.2 years), acquired using a PreXion 3D CBCT unit, were evaluated. All permanent teeth included in the scans were evaluated for the presence of ECR according to the 3-dimensional classification and the portal of entry. The association between the presence of ECR and the factors studied was assessed using the χ2 test. Intra-observer agreement was analyzed with the kappa test (α = 0.05). Results: In total, 6,240 teeth were analyzed, of which 84 (1.35%) were affected by ECR. A significant association was found between the presence of ECR and sex, with a higher prevalence in male patients (p = 0.002). The most frequently affected teeth were the mandibular and maxillary central incisors. The most common height was the mid-third of the root. For the portal of entry, 44% of cases were on the proximal surfaces, 40.5% on the lingual/palatal surface and 15.5% on the buccal surface. Intra-observer agreement was excellent. Conclusions: The prevalence of ECR was 1.35%, with a higher prevalence in male patients and a wide age distribution. The mandibular and maxillary central incisors were the most commonly affected teeth, and cases of ECR most frequently showed a height into the mid-third of the root and proximal entry.

A Study on the Optimal Magnet for ECR (ECR 용 최적 마그네트에 관한 연구)

  • Kim, Y.T.;Kim, Y.J.;Kim, K.S.;Lee, Y.J.;Son, M.H.
    • Proceedings of the KIEE Conference
    • /
    • 1992.07b
    • /
    • pp.649-652
    • /
    • 1992
  • ECR(Electron Cyclotron Resonance) occure at ${\omega}_c$=${\omega}$, ${\omega}_c$:electron cycltron frequency, ${\omega}$:electromagnetic wave frequency. ECR system have several merit, 1) power transefer efficiency 2) low neutral gas pressure (below 1 mTorr) 3) high plasma density($10^{12}$ $cm^{-3}$). It is applicated variously in the field of semiconductor and new materials as the manufacturing equipment. Magnetic field in ECR system contruct resonance layer (${\omega}$=2.45GHz, $B_z$=875 Gauss) and control plasma. Plasma is almost generated at resonance layer. If the distance between substrate and resonance layer is short, uniformity of plasma is related with profile of resonance layer. Plasma have the property "Cold in Field", so directonality of magnetic field is one of the control factors of anisotropic etching. In this study, we calculate B field and flux line distribution, optimize geometry and submagnet current and improve of magnetic field directionality (99.9%) near substrate. For the purpose of calculation, vector potential A(r,z) and magnetic field B(r,z), green function and numerical integration is used. Object function for submagnet optimization is magnetic field directionality on the substrate and Powell method is used as optimization skim.

  • PDF

Effect of Cooled-EGR on the Characteristics of Performance and Exhaust in a HCCI Diesel Engine (균일 예혼합 압축 착화 디젤 엔진의 성능 및 배출물 특성에 미치는 Cooled-EGR 효과)

  • Lee, Chang-Sik;Yoon, Young-Hoon;Kim, Myung-Yoon
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.13 no.5
    • /
    • pp.35-41
    • /
    • 2005
  • The effects of cooled-ECR on the characteristics of combustion and exhaust emissions were investigated in a single cylinder HCCI diesel engine The premixed charge (gasoline or diesel) was obtained with premixing chamber and high-pressure (5.5MPa) injection system. Exhaust pressure control and cooled ECR system were used in order to reduce pressure fluctuation and to mix the exhaust gas well with the fresh intake air. The experimental results show that NOx emissions from conventional diesel engine are steeply decreased by HCCI diesel combustion with cooled-EGR in both case of gasoline and diesel premixing. But soot emissions are rapidly increased with the increase of ECR rate. The recycled exhaust gas increased the ignition delay of mixture and decreased maximum combustion pressure. HC and CO emissions of HCCI combustion are increased with ECR rate.