Schott Ag

Uwe Sahr

Ingo Schwirtlich

Matthias Mueller

Michael Clauss

Markus Finkbeiner

Frank-Thomas Lentes

Frank Buellesfeld

In the method of making a monocrystalline or polycrystalline semiconductor material semiconductor raw material is introduced into a melting crucible and directionally solidified using a vertical gradient freeze method. The molten material trickles downward, so that the raw material that has not yet melted gradually slumps in the melting crucible. The semiconductor raw material is replenished from above onto a zone of semiconductor raw material which has not yet melted or is not completely melted to at least partly compensate for shrinkage of the raw material and to raise the filling level. To reduce the melting time and influence the thermal conditions in the system as little as possible, the semiconductor raw material to be replenished is heated to a temperature below its melting temperature and introduced into the crucible in the heated state.

Method for producing a monocrystalline or polycrystalline semiconductor material

The device for production of a monocrystalline or a multicrystalline material blank, especially a silicon multicrystalline blank, using the VGF method has a crucible with a rectangular or square cross section. A flat heating device, especially a jacket heater, which generates an inhomogeneous temperature profile, is arranged around the crucible. This temperature profile corresponds to the temperature gradient formed in the center of the crucible. The heat output of the flat heating device decreases from the top to the bottom end of the crucible. The flat heating device includes parallel heating webs, which extend in a meandering course. The heat outputs from the heating webs differ according to their different conductor cross sections. To avoid local overheating in corner areas of the crucible, constrictions of the cross sections of the heating webs are provided at inversion zones of their meandering course.

Device for making monocrystalline or multicrystalline materials, in particular multicrystalline silicon

The method of producing monocrystalline or multicrystalline blanks, especially silicon blanks, by using a vertical-gradient-freeze method, includes providing a crucible with a rectangular or square-shaped cross section and a heating jacket disposed around the crucible, which has a number of flat heating elements with a meandering course disposed on side faces of the crucible. The heating jacket generates an inhomogeneous temperature profile corresponding to a temperature gradient in the center of the crucible. The flat heating elements preferably comprise parallel heating webs, whose heat output is set by varying the conductor cross section. To avoid local overheating in corner areas of the crucible, constrictions of the cross section are provided at inversion zones of the meandering courses of the webs. The flat heating elements can be formed from a plurality of interconnected individual segments.

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Nuremberg, Germany

Uwe Sahr