Consortium Fur Elektrochemische Industrie Gmbh

Heliotronic Forschungs- Und Entwicklungsgesellschaft Fur

Helictronic Forschungs- Und Entwicklungs- Gesellschaft Fur

Heliotronic Forshungs Und Entwicklungsgesellschaft Fur Solarzellen

Heliotronic Gmbh

Claus Holm

Josef Dietl

Erhard Sirtl

Jorg Kotilge

Michael Wohlschlager

Franz Holzlwimmer

A process for preparing molded bodies of granular material of silicon, germanium or mixed crystals of these elements. The granular material is introduced into a defined three dimensional mold and a chemical transport reaction is started which proceeds with the transport of silicon or germanium. As a result, the particles of the granular material intergrow with each other and eventually form a solid, porous molded body. By varying the starting material, the transport agent, and by adding dopants, the electrical properties of the product can be varied.

Process for producing molded bodies from granular material of silicon,

Pure silicon is obtained in a semicontinuous process by reducing quartz sand with aluminum in a slag medium based on alkaline earth metal silicates. The slag serves thereby simultaneously as a solvent for the aluminum oxide that forms and as an extraction medium for impurities that occur. The silicon formed separates out of the silicate slag and can be separated off. The aluminum oxide produced by the reduction can be separated from the slag and used for recovery of reusable aluminum.

Semicontinuous process for the production of pure silicon

A process for making doped semiconductor bodies in thick sheets by epitaxial growth of a doped monocrystalline semiconductor layer on a substrate body by means of a transfer reaction, the transfer system being so arranged that dead spaces are avoided and that within the transfer system a gradient of maximally 1.degree. C./mm is maintained. The invention makes it possible to obtain doped layers of larger thickness than heretofore known.

Process for making doped semiconductors

Pure silicon is obtained in a cyclic process by reducing quartz sand with aluminum; the finely divided quartz is dissolved in an aluminum sulphide slag and is reduced by molten aluminum. The molten aluminum also serves as a solvent for the elemental silicon which crystallizes out and precipitates as the temperature falls. Aluminum oxide formed during the reduction is extracted from the slag and passed on for melt electrolysis in order to recover the aluminum.

Semicontinuous process for the manufacture of pure silicon

A method of purifying metallurgical-grade silicon for the production of silicon solar cells is provided, in which metallurgical-grade silicon is dissolved in aluminum and brought into contact with an aluminum sulphide extraction melt. Thereafter, the silicon is crystallized out and separated off by cooling the melt to a minimum temperature of 600.degree. C. The aluminum melt remaining can then be recharged with silicon, heated, brought into contact with the extraction melt, so that additional silicon can be crystallized out.

Growing community of inventors

Baldham, Germany

Claus Holm