• Title, Summary, Keyword: Czochralski silicon crystal

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Influence of relative distance between heater and quartz crucible on temperature profile of hot-zone in Czochralski silicon crystal growth (쵸크랄스키법 실리콘 성장로에서 핫존 온도분포 경향에 대한 히터와 석영도가니의 상대적 위치의 영향)

  • Kim, Kwanghun;Kwon, Sejin;Kim, Ilhwan;Park, Junseong;Shim, Taehun;Park, Jeagun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.28 no.5
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    • pp.179-184
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    • 2018
  • To lessen oxygen concentrations in a wafer through modifying the length of graphite heaters, we investigated the influence of relative distance from heater to quartz crucible on temperature profile of hot-zone in Czochralski silicon-crystal growth by simulation. In particular, ATC temperature and power profiles as a function of different ingot body positions were investigated for five different heater designs; (a) typical side heater (SH), (b) short side heater-up (SSH-up), (c) short side heater-low (SSH-low), (d) bottom heater without side heater (Only-BH), and (e) side heater with bottom heater (SH + BH). It was confirmed that lower short side heater exhibited the highest ATC temperature, which was attributed to the longest distance from triple point to heater center. In addition, for the viewpoint of energy efficiency, it was observed that the typical side heater showed the lowest power because it heated more area of quartz crucible than that of others. This result provides the possibility to predict the feed-forward delta temperature profile as a function of various heater designs.

Effect of buoyancy and thermocapillarity on the melt motion and mass transfer for different aspect ratio of flow field in magnetic Czochralski crystal growth of silicon (Cusp 자장이 걸려있는 초크랄스키 실리콘 단결정성장에서 유동장의 종횡비에 따라 부력과 열모세관 현상이 용융물질의 유동과 물질전달에 미치는 영향)

  • 김창녕
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.10 no.3
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    • pp.177-184
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    • 2000
  • The effect of the buyancy and thermocapillarity for differnent aspect ratio of flow field on melt motion and mass transfer has been numerically investigated in magnetic Czochralski crystal growth of silicon. During the process of crystal growth, the melt depth of crucible reduces so the aspect ratio of flow field also reduces. Therefore the shape of magnetic field of the flow field changes and the flow pattern also changes significantly. Together with the melt flow which forms the Marangoni convection (or thermocapillary flow) that comes from the inside the flow field, a flow circulation is observed near the corner close both to the crucible wall and the free surface. Due to this circulation, buoyancy effect has been turned out to be local rather than global. As the aspect ratio decreases, the radial component of the magnetic field prevails compared with the axial component in the flow field. Under the influence of this magnetic field, the melt flow and the temperature distribution in a meridional plane tend to depend on the radial position. As the aspect ratio decreases, the temperature gradient near the edge of the crystal decreases yielding smaller thermocapillarity, and the oxygen concentration near the crystal and the oxygen incorporation rate also decrease.

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Measurement of Velocity and Temperature Field at the Low Prand시 Number Melt Model of the CZ Crystal Growth

  • Kim, Min-Cheol;Lee, Sang-Ho;Yi, Kyung-Woo
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • pp.169-172
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    • 1998
  • A phyaical model of the Czochralski method for silicon single crystals is designed to measure the change of velocities and temperature profilles in the melt. Wood's metal(Bi 50%, Pb 26.7%, Sn 13.3%, Cd 10%, m.p. 70℃) is used to simulate the silicon melt in the crucible. To measure the local velocity change, electromagnetic probe is adopted as a velocity sensor. The output voltage of the sensor shows linear relationship to the velocity of the melt.

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GSMAC-FEM Analysis of Single-Crystal Growth by CUSP MCZ Method

  • Jung, Chung-Hyo;Takahiko Tanahashi;Yuji Ogawa
    • Journal of Mechanical Science and Technology
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    • v.15 no.12
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    • pp.1876-1881
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    • 2001
  • We present the numerical analysis of the growth of a silicon (Si) single crystal. In the MCZ (Magnetic-field-applied Czochralski) method, two magnetic fields that stand opposite to each other generate a cusp magnetic field. In this work, the three cusp magnetic fields used for the analysis are an extern magnetic field, a surface magnetic field and an internal magnetic field. Each case was evaluated mainly as to the degree of stirring, shaft symmetry and the stability of the flow. As a result, the cusp magnetic field that yielded to best conditions was the internal magneic field.

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Comparison of numerical simulation and experiment for the OiSF-Ring diameter in czochralski-grown silicon crystal

  • Oh, Hyun-Jung;Wang, Jong-Hoe;Yoo, Hak-Do
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.10 no.5
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    • pp.356-361
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    • 2000
  • The radial position of OiSF-ring has been meaningful data in industry. Thus it's position was calculated by application of (V/G)/sub crit/ = 0.138 ㎟/minK and point defect dynamics for industrial scale grower with various pull rates. After the calculation, compared with experimental result. OiSF-ring diameters expected with calculation were good agreement with experimental results. In order to show validity of the predicted temperature distribution using STHAMAS which is one of the global simulator for Cz crystal growing, temperature was measured along the axis of crystal using thermocouples, and compared with the calculated temperature. We found the effective thermal conductivity K/sub m/ (r) which gives in accordance with the temperature distribution at the axis of crystal and crystal/melt interface shape between experimental and computational results. Therefore, effective thermal conductivity K/sub m/ (r) was applied instead of solving melt convection problem.

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A numerical study on the optimum operation condition for axial oxygen concentration in 8 inch silicon growth by cusp MCZ (8인치 실리콘성장을 위한 커스프 MCZ계에서 축방향 산소분포에 대한 연구)

  • 이승철;윤종규
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.7 no.3
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    • pp.406-417
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    • 1997
  • A numerical study was conducted on the optimum magnetic field intensity and asymmetric factor for uniform axial oxygen concentration in 8 inch silicon single crystal growing process by magnetic Czochralski method. For constant shape of cusp field, a change of coil and crucible position were compared. In case of symmetric cusp field, magnetic field intensity variation shows concave downward with crystal growing for uniform, axial oxygen concentration. A numerical results show similar value of standard deviation of average oxygen concentration for uniform oxygen concentration between coil and crucible position change. In case of asymmetric cusp field. asymmetric factor is increased with crystal growing to have uniform oxygen concentration.

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A study on point defects induced with neutron irradiation in silicon wafer (중성자 조사에 의해 생성된 점결함 연구)

  • 김진현;류근걸
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.62-66
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    • 2002
  • The conventional floating zone(FZ) crystal and Czochralski(CZ) silicon crystal have resistivity variations longitudinally as well as radially The resistivity variations of the conventional FZ and CZ crystal are not conformed to requirement of dopant distribution for power devices and thyristors. These resistivity variations in conventional cystals limits the reverse breakdown voltage that could be achieved and forced designers of high power diodes and thyristors to compromise the desired current-voltage characteristics. So to produce high Power diodes and thyristors, Neutron Transmutation Doping(NTD) technique is the one method just because NTD silicon provides very homogeneous distribution of doping concentration. This procedure involves the nuclear transmutation of silicon to phosphorus by bombardment of neutron to the crystal according to the reaction $^{30}$ Si(n,${\gamma}$)longrightarrow$^{31}$ Silongrightarrow(2.6 hr)$^{31}$ P+$\beta$$^{[-10]}$ . The radioactive isotope $^{31}$ Si is formed by $^{31}$ Si capturing a neutron, which then decays into the stable $^{31}$ P isotope (i.e., the donor atom), whose distribution is not dependent on the crystal growth parameters. In this research, neutron was irradiated on FZ silicon wafers which had high resistivity(1000~2000 Ω cm), for 26 and 8.3hours for samples of HTS-1 and HTS-2, and 13, 3.2, 2.0 hours for samples of IP-1, IP-2 and IP-3, respectively, to compare resistivity changes due to time differences. The designed resistivities were approached, which were 2.l Ωcm for HTS-1, 7.21 Ω cm for HTS-2, 1.792cm for IP-1, 6.83 Ωcm for IP-2, 9.23 Ωcm for IP-3, respectively. Point defects were investigated with Deep Level Transient Spectroscopy(DLTS). Four different defects were observed at 80K, 125K, 230K, and above 300K.

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A Numerical study of the fluctuation behavior of the oxygen concentration and the temperature in the silicon melt of Czochralski crystal growth system

  • Yi, Kyung-Woo;Kim, Min-Cheol
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • pp.197-201
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    • 1997
  • The momentum, heat and mass trasfer phenomena in the silicon melt of the Czochralki crystal growth system are calculated using a three dimensional numerical simulation thechnique. Even though axisymmetrical boundary conditions are imposed to all calculations in a 3cm diameter crucible, several types of non-axisymmetric profiles of velocities, temperature and oxygen concentration appeared in the melt. Because of the non-axisymmetric profiles of velocities, temperature and oxygen concentration appeared in the melt. Because of the non-axisymmetric profiles and rotations of fluid induced by the crucible rotation, temperatures and oxygen concentrations in the silicon melt fluctuate. The rotating velocity of the profile is calculated from the phase shift of the data of temperature or oxygen at two different points which have same radius from center but 90 degree angular difference. From this calculation, it is found that the rotating veolocity of the oxygen and temperature is different from the crucible rotation rates. Therefore the frequencies of the oscillating temperature and oxygen concentrations are not same to the frequencies of the crucible rotations. Futhermore, the components of the frequencies of the temperature and oxygen concentration at the same point are not same. The fluctuation behaviors of the temperature or oxygen themselves are also different when the points are different. The calculation show that the temperature and the oxygen concentration near the interface also fluctuate. The results suggest that the striation pattern found in the grown silicon single crystals may ben generated by the oxygen concentration and the temperature oscillations of the melt occurred near the interface.

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Estimation of mechanical damage by minority carrier recombination lifetime and near surface micro defect in silicon wafer (실리콘 웨이퍼에서 소수 반송자 재결합 수명과 표면 부위 미세 결함에 의한 기계적 손상 평가)

  • 최치영;조상희
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.2
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    • pp.157-161
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    • 1999
  • We investigated the effect of mechanical back side damage in Czochralski silicon wafer. The intensity of mechanical damage was evaluated by minority carrier recombination lifetime by laser excitation/microwave reflection photoconductance decay ($\mu$-PCD) technique, wet oxidation/preferential etching methods, near surface micro defect (NSMD) analysis, and X-ray section topography. The data indicate that the higher the mechanical damage intensity, the lower the minority carrier lifetime, and NSMD density increased proportionally, also correlated to the oxidation induced stacking fault (OISF) density. Thus, NSMD technique can be used separately from conventional etching method in OISF measurement.

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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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