Abstract: Granular polycrystalline silicon includes a compact matrix including radiating acicular crystal aggregates of crystal size from 0.001-200 ?m. A process for producing granular polycrystalline silicon includes producing granular silicon in a fluidized bed reactor from a gas mixture containing TCS (20-29 mol %) and hydrogen at a fluidized bed temperature of 900-970° C., dividing the granular silicon in a screen system having at least one screen deck into at least two screen fractions, the smallest screen fraction being ground in a grinding system to give seed particles having a size of 100-1500 ?m and a mass-based median value from 400 to 900 ?m, and these seed particles being supplied to fluidized bed reactor, and a further screen fraction being supplied to a fluidized bed reactor, and being surface-treated with a gas mixture containing TCS (5.1-10 mol %) and hydrogen at a fluidized bed temperature of 870-990° C.

Abstract: A method for the contamination-free heating of a highly pure gas to a temperature of from 300 to 1200° C. involves passing the highly pure gas at a pressure of from 0.1 to 10 bar abs. over a highly pure solid which does not contaminate the gas, the solid being present in a highly pure container whose wall consists of a material which has a transparency of more than 85% for infrared rays and the container being irradiated by means of the infrared rays, the solid being heated thereby and the solid heating the gas.

Abstract: High-purity polysilicon granules are prepared by depositing reaction gas on silicon granules in a fluidized bed reactor having: a reactor space comprising at least two zones lying one above the other, the lower zone weakly fluidized by introduction of a silicon-free gas into silicon granules in the lower zone by a plurality of individual dilution gas nozzles, and a second, reaction zone directly abutting the lower zone, the reaction zone heated via its outwardly bounding wall, introducing silicon-containing reaction gas as a vertical high speed gas jet into the reaction zone by reaction gas nozzle(s), forming local reaction gas jets surrounded by bubble-forming fluidized bed, gas decomposing leading to particle growth, wherein the reaction gas has fully or almost fully reacted to chemical equilibrium conversion before reaching the wall or bed surface.

Abstract: Granular polycrystalline silicon includes a compact matrix including radiating acicular crystal aggregates of crystal size from 0.001-200 ?m. A process for producing granular polycrystalline silicon includes producing granular silicon in a fluidized bed reactor from a gas mixture containing TCS (20-29 mol %) and hydrogen at a fluidized bed temperature of 900-970° C., dividing the granular silicon in a screen system having at least one screen deck into at least two screen fractions, the smallest screen fraction being ground in a grinding system to give seed particles having a size of 100-1500 ?m and a mass-based median value from 400 to 900 ?m, and these seed particles being supplied to fluidized bed reactor, and a further screen fraction being supplied to a fluidized bed reactor, and being surface-treated with a gas mixture containing TCS (5.1-10 mol %) and hydrogen at a fluidized bed temperature of 870-990° C.

Abstract: A polycrystalline granulated silicon is made of particles which have a density of greater than 99.9% of the theoretical solid density and therefore have a pore content of less than 0.1% and have a surface roughness Ra of less than 150 nm.

Abstract: An apparatus for producing silicon seed particles having a size of from 50 ?m to 1000 ?m from silicon granules having a size of from 300 ?m to 5000 ?m, comprising a vertically disposed jet chamber with a low cross sectional area and a jet nozzle at the base of the jet chamber through which a milling gas stream is introduced into the chamber; a larger cross section countercurrent gravity separator adjoining the jet chamber, and an inlet for silicon granules, wherein the jet chamber has a length sufficient to allow the milling gas stream to widen to the cross section of the jet chamber.

Abstract: High-purity polysilicon granules are prepared by depositing reaction gas on silicon granules in a fluidized bed reactor having: a reactor space comprising at least two zones lying one above the other, the lower zone weakly fluidized by introduction of a silicon-free gas into silicon granules in the lower zone by a plurality of individual dilution gas nozzles, and a second, reaction zone directly abutting the lower zone, the reaction zone heated via its outwardly bounding wall, introducing silicon-containing reaction gas as a vertical high speed gas jet into the reaction zone by reaction gas nozzle(s), forming local reaction gas jets surrounded by bubble-forming fluidized bed, gas decomposing leading to particle growth, wherein the reaction gas has fully or almost fully reacted to chemical equilibrium conversion before reaching the wall or bed surface.

Abstract: A method for the contamination-free heating of a highly pure gas to a temperature of from 300 to 1200° C. involves passing the highly pure gas at a pressure of from 0.1 to 10 bar abs. over a highly pure solid which does not contaminate the gas, the solid being present in a highly pure container whose wall consists of a material which has a transparency of more than 85% for infrared rays and the container being irradiated by means of the infrared rays, the solid being heated thereby and the solid heating the gas.

Abstract: An apparatus for producing silicon seed particles having a size of from 50 ?m to 1000 ?m from silicon granules having a size of from 300 ?m to 5000 ?m, comprising a vertically disposed jet chamber with a low cross sectional area and a jet nozzle at the base of the jet chamber through which a milling gas stream is introduced into the chamber; a larger cross section countercurrent gravity separator adjoining the jet chamber, and an inlet for silicon granules, wherein the jet chamber has a length sufficient to allow the milling gas stream to widen to the cross section of the jet chamber.

Abstract: A radiation-heated fluidized-bed reactor and a process for producing high-purity polycrystalline silicon by using this reactor are provided. In this reactor, a heater device (14) is a radiation source for thermal radiation which is arranged outside the inner reactor tube and as a cylinder around the heater zone, without being in direct contact with the inner reactor tube. The inner reactor tube is designed in such a manner that it uses thermal radiation to heat the silicon particles in the heating zone to a temperature which is such that the reaction temperature is established in the reaction zone.

Abstract: A polycrystalline granulated silicon is made of particles which have a density of greater than 99.9% of the theoretical solid density and therefore have a pore content of less than 0.1% and have a surface roughness Ra of less than 150 nm.