Wacker-chemitronic Gesellschaft Fur Elektronik-grundstoffe Mbh

Heliotronic Forschungs- Und Entwicklungsgesellschaft Fur

Helictronic Forschungs- Und Entwicklungs- Gesellschaft Fur

Consortium Fur Elektrochemische Industrie Gmbh

Heliotronic Gmbh

Erhard Sirtl

Josef Dietl

Heinz-Jorg Rath

Claus Holm

Franz Koppl

Rudolf Griesshammer

Dieter Seifert

Winfried Lang

Bernhard Authier

Dieter Helmreich

Cord Gessert

Erich Bildl

Hans-Dieter Miller

Gerhard Ast

Herbert Pichler

Theo Zollner

Rudolf Rothlehner

Franz Holzlwimmer

Hermann Dicker

Rolf Bauregger

A novel material can be obtained by chemical reaction from elemental or alloyed silicon powder, to which fillers are optionally added. The novel material, which can be worked mechanically, can be further refined by means of subsequent heat treatment and/or surface coating, and can in many cases be used instead of polycrystalline or sintered silicon.

Material comprising silicon and process for its manufacture

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,

The invention relates to a process for the direct manufacture of semiconductor wafers, wherein the semiconductor wafers are obtained from molten semiconductor material by providing an area of the surface of the semiconductor melt that corresponds approximately to the size of the wafer with at least one seed crystal, by allowing this area of the surface to cool until it solidifies, the cooling being brought about at least substantially by loss of heat by radiation, and finally, by removing the crystallized-out wafer from the surface. If elemental silicon is used as the semiconductor material, wafers that are suitable for further processing to form solar cells are obtained.

Process for the manufacture of semiconductor wafers

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

Competitive current generation by the exploitation of solar energy requires cheap solar cells. A process is described which makes it possible to manufacture from silicon a base material for solar cells of this type in an economical manner and in large quantities. This is achieved by bringing silicon from a supply container into contact with a non-elemental lubricating melt, which is immiscible with silicon but will not wet silicon and has a melting point below that of silicon, and by drawing off a silicon film, sliding on this lubricating melt, and solidifying the silicon continuously by cooling to below its' melting point.

Process for making solar cell base material

To make solar energy competitive, as compared against other sources of energy, inexpensive solar cells are required. To accomplish this goal, a method is provided which enables one to produce silicon rods having a columnar structure made of monocrystalline zones with preferential crystallographic orientation. This is effected by feeding a silicon melt into a crystallization chamber having a vertically movable cooled bottom face under the influence of a temperature gradient directed parallel to the rod axis, so that the rods can be made continuously or semicontinuously with high drawing speeds.

Method for making silicon rods

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

The invention relates to the preparation of a material more favorably pri that the usual quartz crucible for use in the crucible-pulling of silicon according to Czochralski. To prevent reaction of the crucible wall with molten silicon, the surface of the shaped carbon body is coated by means of chemical vapor deposition first with a carbon-enriched silicon carbide layer and then with a carbon-enriched silicon nitride layer. The carbon-enriched silicon carbide layer is obtained by reacting a gaseous silicon compound with a gaseous carbon compound at a temperature of the shaped carbon body to be coated at 1250.degree. to 1350.degree. C. while the carbon-enriched silicon nitride layer is obtained by reacting a gaseous organosilicon compound with ammonia at a temperature of the shaped carbon body of 1000.degree. to 1200.degree. C.

Process for applying a protective layer to shaped carbon bodies

Process for producing large-size, self-supporting plates of silicon deposd from the gaseous phase on a substrate body, which comprises heating a graphite substrate to deposition temperature of silicon, which is deposited on the substrate from a gaseous compound to which a dopant has been added until a layer of about 200 to 650 .mu.m has formed, subsequently melting 40-100% of this layer from the free surface downward, resolidifying the molten silicon by adjustment of a temperature gradient from the substrate body upward, and finally separating the silicon therefrom. The plates so formed are used primarily for making solar cells.

Process for producing large-size, self-supporting plates of silicon

A process for producing large-size, substrate-based semiconductor material of silicon deposited on a substrate body from the gaseous phase, which comprises the steps of heating a substrate body by direct current passage to deposition temperature, contacting said body with a gaseous silicon-containing mixture to which a dopant has been added, until a deposit having a thickness from about 10 to 200 .mu.m has been formed, subsequently melting 80 to 100% of the deposited silicon layer from the free surface downward, and resolidifying the molten silicon by adjustment of a temperature gradient from the substrate body upward. Large-sized plates obtained by cutting up the semiconductor material are used as solar cells.

Growing community of inventors

Marktl, Germany

Erhard Sirtl