Wacker-chemitronic Gesellschaft Fur Elektronik-grundstoffe Mbh

Siltronic Ag

Lothar Huber

Georg Priewasser

Peter Wiesner

Holger Lundt

Horst Stock

Gerhard Spatzier

A method for cutting up a workpiece which is in rod or block form by means of a saw, wherein the temperature of the workpiece is measured during the cutting, and the measurement signal is transmitted to a control unit, which generates a control signal which is used to control the temperature of the workpiece, or wherein the temperature of the workpiece is controlled during the cutting by a control signal based on a predetermined control curve.

Method for cutting slices from a workpiece

By means of the process and by means of the apparatus, fused silicon is produced continuously, or in phases, and zonally cast into a mold in which it is caused to solidify zonally. The temperature conditions in the solidification zone are controlled with the aid of a movable heating zone, by means of which the crystallization front is adjusted to the rising level that fills up the mold, this level being in turn controlled by the fusion rate of the silicon. Polycrystalline silicon blocks can be obtained in which, because of the flat shape of the crystallization front, the columnar single-crystal domains within the blocks extend almost vertically and which represent an excellent solar cell base material having high diffusion lengths and lifetimes of the minority charge carriers, from which solar cells of correspondingly high efficiencies can be produced.

Process for casting silicon blocks of columnar structure

A process and apparatus for the manufacture of silicon rods having a colur structure comprising monocrystalline crystal zones with a crystallographic preferred orientation. Molten silicon is transferred from a silicon reservoir into a crystallization chamber which is formed by rollers arranged in a leak-proof manner in the shape of the desired rod cross-section. There the silicon first forms a stable outer shell of solidified material and, while it continues to crystallize, it is withdrawn at the bottom and released by the rollers. Owing to the short period of contact with a vessel wall a silicon rod is obtained that is particularly free of impurites.

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Burghausen, Germany

Lothar Huber