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US 5,487,354 AGranted
Method for pulling a silicon single crystal
AssigneeWacker-Chemitronic Gesellschaft fuer Eletronik-Grundstoffe mbH
InventorsWilfried von Ammon, Erich Dornberger, Hans Oelkrug, Peter Gerlach, Franz Segieth
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Abstract
A method for pulling a silicon single crystal has the single crystal being pulled at a speed defined as maximum pulling speed in the vertical direction with respect to a silicon melt held in a crucible. The value of the maximum pulling speed is approximately proportional to the axial temperature gradient in the growing single crystal.
Claims6
A method for pulling a single crystal in the vertical direction with respect to a silicon melt held in a crucible, which method comprises
- pulling the single crystal having a solid/liquid phase boundary at a speed which is not higher than a maximum pulling speed (.sup.v crit) which is calculated according to the empirical formula
- .sup.v crit=f*G
- where f is a proportionality factor having the value 13*10.sup.-4 cm.sup.2 /K*min and
- G is an axial temperature gradient in the region of the solid/liquid phase boundary of the growing single crystal in the unit [K/cm] and the maximum pulling speed .sup.v crit is obtained in the unit [cm/min].
1 more element
Dependencies are inferred from the claim text.