Abstract: A plate-like silicon crystal having a columnar structure formed along the direction of the shortest axis, produced by cooling molten silicon, which may contain a doping agent, in a temperature gradient between the two largest boundary surfaces of the melt, one of which has a maximum temperature of 1200.degree. C., and the opposite surface being at least 200.degree. to 1000.degree. C. higher, but below the melting point of silicon.

Abstract: The invention relates to a process and apparatus for manufacturing silicon astings or moldings, having a columnar structure of single-crystal regions of crystal with a preferential crystallographic orientation, and which can be manufactured cheaply and in large numbers in a semi-continuous mode of production. Liquid silicon is cast in a casting station, under an inert gas and preferably under reduced pressure, preferably in graphite molds which are exposed to a temperature gradient of 200.degree. to 1,000.degree. C. After cooling, the silicon is withdrawn automatically via a transport chamber connected to the casting station into special cooling stations, while the casting station is reloaded with an empty mold for repeating the process. The silicon blocks which have preferably been produced by this procedure are use as basic material for inexpensive solar cells having efficiencies of more than 10%, after they have been sawn into individual small wafers and have been doped and lead-bonded.

Abstract: Process for the manufacture of silicon of large surface area bonded to a substrate, which comprises depositing silicon to a thickness of from 30 to 500 .mu.m onto panel-shaped substrates of glassy carbon (a glass-like carbon obtained by carbonizing a spatially cross-linked synthetic resin) that are heated by direct passage of an electric current to temperatures above the melting point of silicon, and thereafter cooling the silicon to a temperature below its melting point in the direction from its free surface toward the substrate. The invention also comprises the silicon panels so made which are especially useful in the manufacture of solar cells.

Abstract: 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.

Abstract: 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.