• Proceedings of the Materials Research Society of Korea Conference
• /
• 2007.11a
• /
• pp.13.1-13.1
• /
• 2007

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2008.05a
• /
• pp.30.2-30.2
• /
• 2008

• 대한방사선방어학회:학술대회논문집
• /
• 2009.11a
• /
• pp.166-167
• /
• 2009

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.8 no.1
• /
• pp.18-28
• /
• 1998

A laboratory experiment was made of a control of temperature oscillation in Czochralski convection. Numerical computation was also made to delineate the control of temperature oscillation. The suppression of temperature oscillation was achieved by varying the rotation rate of crystal rod ($\Omega=\Omega_0(1+A sin 2{\pi}ft/t_p)$), where A denotes the amplitude of rotation rate and f the frequency factor. Based on the inherent dimesionless time period of temperature oscillation ($t_p$), the suppression rate of temperature oscillation was characterized by the mixed convection parameter ($0.217{\leq}Ra/PrRe^2{\leq}1.658$). The optimal values of A and f were also scrutinized. To understand the suppression mechanism of temperature oscillation, the controls of isotherm($\theta$) and equi-vorticity($\omega$) were investigated.

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

• Proceedings of the Korea Crystallographic Association Conference
• /
• 2001.05a
• /
• pp.27-27
• /
• 2001

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.9 no.2
• /
• pp.149-156
• /
• 1999

An experimental simulation on the flow in Czochralski melt using a cold model was carried out to obtain the velocities of fluid flow which affects the oxygen concentration of Czochralski crystal growing system. Low melting point Woods metal with similar Pr number to the silicon melt was adopted as a working fluid. Local flow velocities at numerous positions in the melt were simulataneously measured in three dimension using incorporated magnet probe. The measured velocity field showed a non-axisymmetric pattern dominated by natural convection. The analysis on the correlation between data set of temperatures simultaneously measured at two melt positions showed that the values of correlation coefficients were smaller than those of previous study on the small size of silicon melt and these phenomena are believed to occur because turbulent behavior becomes stronger in large size of the melt.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2005.05a
• /
• pp.259-259
• /
• 2005

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.7 no.4
• /
• pp.536-547
• /
• 1997

For various angular velocities of crucible and crystal, the characteristics of melt flows, temperatures and concentrations of oxygen are numerically studied in the Czochralski furnace with a uniform axial magnetic field. Buoyancy effect due to the heating of crucible wall and thermocapillary effect due to the temperature gradient at the free surface, can be differentiably suppressed by the centrifugal forces due to the rotations of the crucible and crystal. The most important factor which yields the centrifugal forces is the rotation velocity of the crucible, that influences the fields of velocities, temperatures and concentrations. In the case that the crucible rotation velocity is not high, the rotations of the crystal gives rise to the centrifugal forces effectively.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.7 no.1
• /
• pp.108-116
• /
• 1997

A laboratory experiment was made of critical transition flow modes in Czocllralski convection. Numerical computation was also made to delineate the dynamic transition. The period of temperature oscillation ($t_p$) and the interval of temperature oscillation ($\Delta\theta$) were scrutinized to capture the critical transition regime. The mixed convection parameter was varied in the range of $0.134\le Ra/PrRe^2 \le3.804$. The data from calculation were in good agreement with ones from experiment. The influence of the Prandtl number on the transition was examined for Pr ＝ 910, 4445 and 8889. To understand the transition mechanism, the detailed temperature oscillation modes, the isolines of meridional temperature and the axial velocity profiles were investigated.