Control of oscillatory Czochralski convection by ACRT

Title & Authors
Control of oscillatory Czochralski convection by ACRT
Choe, Jeong-Il; Seong, Hyeong-Jin;

Abstract
A numerical study was made of the control of transient oscillatory flow modes in Czochralski convection. The reduction of temperature oscillation was achieved by changing the rotation rate of crystal rod, .OMEGA.$\small{_{S}}$=.OMEG $\small{A_{S0}}$(1+ $\small{A_{S}}$sin(2.pi. $\small{f_{S}}$/ $\small{t_{p}}$t)). The temporal behavior of oscillation flow was scrutinized over broad ranges of two parameters, i.e., the rotation amplitude( $\small{A_{S}}$.leq.0.5) and the nondimensional frequency (0.9.leq. $\small{f_{S}}$.leq.1.5). The mixed convection parameter was ranged 0.225.leq.Ra/PrR $\small{e^{2}}$.leq.0.929, which encompassed the buoyancy-and forced-dominant convection regimes. Computational results revealed that the temperature oscillations could be reduced effectively by a proper adjustment of the control parameters. The uniformity of temperature distribution near the crystal rod was examined. The control of oscillatory flow modes was also made for a realistic, low value of Pr.
Keywords
Czochralski Convection;Accerelated Crucible/Crystal Rotation Technique;Single Crystal Growth;Striation Control;Crystal/Melt Interface Homogeneity;
Language
Korean
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