• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.4
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• pp.137-139
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• 2008

Floating zone, neutron transmutation-doped and magnetic Czochralski silicon crystals are being widely used for fabrication power devices. To improve the quality of these devices and to decrease their production cost, it is necessary to use large-diameter wafers with high and uniform resistivity. Recent developments in the crystal growth technology of Czochralski silicon have enable to produce Czochralski silicon wafers with sufficient resistivity and with well-controlled, suitable concentration of oxygen. In addition, using Czoehralski silicon for substrate materials may offer economical benefits, First, Czoehralski silicon wafers might be cheaper than standard floating zone silicon wafers, Second, Czoehralski wafers are available up to diameter of 300 mm. Thus, very large area devices could be manufactured, which would entail significant saving in the costs, In this work, the conventional Czochralski silicon crystals were grown with higher oxygen concentrations using high pure polysilicon crystals. The silicon wafers were annealed by several steps in order to obtain saturated oxygen precipitation. In those wafers high resistivity over $5,000{\Omega}$ cm is kept even after thermal donor formation annealing.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.3
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• pp.119-123
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• 2013

Most of the world's solar cells in photovoltaic industry are currently fabricated using crystalline silicon. Czochralski-grown silicon crystals are more expensive than multicrystalline silicon crystals. The future of solar-grade Czochralski-grown silicon crystals crucially depends on whether it is usable for the mass-production of high-efficiency solar cells or not. It is generally believed that the main obstacle for making solar-grade Czochralski-grown silicon crystals a perfect high-efficiency solar cell material is presently light-induced degradation problem. In this work, the substitution of boron with gallium in p-type silicon single crystal is studied as an alternative to reduce the extent of lifetime degradation. The diamond-wire sawing technology is employed to slice the silicon ingot. In this paper, the quality of the diamond wire-sawn gallium-doped silicon wafers is studied from the chemical, electrical and structural points of view. It is found that the characteristic of gallium-doped silicon wafers including texturing behavior and surface metallic impurities are same as that of conventional boron-doped Czochralski crystals.

• Proceedings of the Materials Research Society of Korea Conference
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• 1995.11a
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• pp.31-31
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• 1995

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.17-20
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• 1998

Thermal behavior of Flow Pattern Defect (FPD) and Large Pit (LP) in Czochralski Silicon crystals was investigated by applying high temperature ($\geq$1100$^{\circ}C$) annealing and non-agitation Secco etching. For evaluation of the effect of LP upon device performance / yield, DRAM and ASIC devices were fabricated. The results indicate that high temperature annealing generates LPs whereas it decreases FPD density drastically, and LP does not have detrimental effects on the performance /

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.4
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• pp.129-134
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• 2005

A numerical analysis was performed on magnetic field effects of silicon melt motion in Czochralski crystal puller. The turbulent modeling was used to simulate the transport phenomena in 18' single crystal growing process. For small crucible angular velocity, the natural convection is dominant. As the crucible angular velocity is increased, the forced convection is increased and the distribution of temperature profiles is broadened. The cusp magnetic field reduces effectively the natural and forced convection near the crucible and the temperature profiles of the silicon fluids is similar in the case of conduction.

• International Journal of Control, Automation, and Systems
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• v.3 no.2
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• pp.252-257
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• 2005

In this work, we propose a simple but efficient method to design a target temperature trajectory for pulling speed tracking control of the crystal grower in the Czochralski crystallization process. In the suggested method, the model predictive control strategy is used to incorporate the complex dynamic effect of the heater temperature on the pulling speed into the temperature trajectory design quantitatively. The feedforward trajectories designed by the proposed method were implemented on 200 mm and 300 mm silicon crystal growers in the commercial Czochralski process. The application results have demonstrated its excellent and consistent tracking performance of pulling speed along whole bulk crystal growth.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.1
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• pp.27-40
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• 1997

The heat in Czochralski method is transfered by all transport mechanisms such as convection, conduction and radiation and convection is caused by the temperature difference in the molden pool, the rotations of crystal or crucible and the difference of surface tension. This study delvelops the simulation model of Czochralski growth by using the finite difference method with fixed grids combined with new latent heat treatment model. The radiative heat transfer occured in the surfce of the system is treated by calculating the view factors among surface elements. The model shows that the flow is turbulent, therefore, turbulent modeling must be used to simulate the transport phenomena in the real system applied to 8" Si single crystal growth process. The effects of a cusp magnetic field imposed on the Czochralski silicon melt are studied by numerical analysis. The cusp magnetic field reduces the natural and forced convection due to the rotation of crystal and crucible very effectively. It is shown that the oxygen concentration distribution on the melt/crystal interface is sensitively controlled by the change of the magnetic field intensity. This provides an interesting way to tune the desired O concentration in the crystal during the crystal growing.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.6
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• pp.259-263
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• 2001

The continuum model of transient point defect dynamics to predict the concentrations of interstitial and vacancy is established by estimating expressions for the thermophysical properties of intrinsic point defects. And the point defect distribution in a Czochralski-grown 200 mm silicon crystal and the location of oxidation-induced stacking fault ring(OiSF-ring) created during the cooling of crystals are calculated by using the numerical analysis. The purpose of this paper is to show that his approach lead to predictions that are consistent with experimental results. Predicted point defect distributions by transient point defect dynamic analysis are in good qualitative agreement with experimental data under widely and abruptly varying crystal pull rates when correlated with the position of the OiSF-ring .

• Korean Journal of Metals and Materials
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• v.47 no.11
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• pp.734-739
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• 2009

It is well known that the temperature and the flow pattern of the crystal-melt interface affect the qualities of the single crystal in the Czochralski process. Thus the temperature profile in the growth system is very important information. This work focuses on controlling the temperature of the silicon melt with a thermal gradient of the crucible. Therefore, the side heater is divided into three parts and an extra heater is added at the bottom for thermal gradient. The temperature of the silicon melt can be strongly influenced and controlled by the electric power of each heater.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.4
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• pp.141-147
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• 2018

Solar energy has attracted big attentions as one of clean and unlimited renewable energy. Solar energy is transformed to electrical energy by solar cells which are comprised of multi-silicon wafer or mono-silicon wafer. Monosilicon wafers are fabricated from the Czochralski method. In order to decrease fabrication cost, increasing a poly-silicon charge size in one quartz crucible has been developed very much. When we increase a charge size, the temperature control of a Czochralski equipment becomes more difficult due to a strong melt convection. In this study, we simulated a Czochralski equipment temperature at 20 inch and 24 inch in quartz crucible diameter and various charge sizes (90 kg, 120 kg, 150 kg, 200 kg, 250 kg). The simulated temperature profiles are compared with real temperature profiles and analyzed. It turns out that the simulated temperature profiles and real temperature profiles are in good agreement. We can use a simulated profile for the optimization of real temperature profile in the case of increasing charge sizes.