Abstract: A process and a device for producing crystalline silicon, particularly poly- or multi-crystalline silicon are described, wherein a melt of a silicon starting material is formed and the silicon melt is subsequently solidified in a directed orientation. A phase or a material is provided in gaseous, fluid or solid form above the melt in such a manner, that a concentration of a foreign atom selected from oxygen, carbon and nitrogen in the silicon melt and thus in the solidified crystalline silicon is controllable, and/or that a partial pressure of a gaseous component in a gas phase above the silicon melt is adjustable and/or controllable, the gaseous component being selected from oxygen gas, carbon gas and nitrogen gas and gaseous species containing at least one element selected from oxygen, carbon and nitrogen.

Abstract: A device is made available for producing monocrystals, for example large-diameter gallium arsenide monocrystals, that has a cylindrical heating appliance with a floor heater (2) and a cover heater (3). The heating surfaces of the floor and the cover heater are considerably larger than the cross-sectional area of the monocrystal to be produced. In addition, an insulator (6) is planned for the reaction space that is designed to prevent a radial heat flow and the guarantee a strictly axial heat flow over the complete height of the reaction space between the cover heater (3) and the floor heater (2).