Patent ID: 6027563
Filing Date: 2000-02-22
Classification: C30B,H01L,Y02E,Y02P,Y10T

Abstract:
A method for the oriented solidification of molten silicon to form an ingot in a bottomless slotted cold-wall crucible which is surrounded by an induction coil, having a supporting body which bears the ingot and which is removed from the cold-wall crucible with the already solidified part of the ingot by a relative movement in proportion to further silicon feed and solidification rate, the silicon being adjusted to a temperature at which it is indictively heated by its electrical conductivity, wherein(a) on the hollow metal supporting body configured as a cooling body, a seed body initially at least largely closing the cold-wall crucible and having an axially parallel crystal structure from the coarsely crystalline to monocrystalline group is placed with broad-surface contact and is superficially melted by the molten silicon,(b) a preloaded amount of lump silicon is preheated from above by radiation heating until a sufficient electrical conductivity is reached, and(c) the cooling body is left at first uncooled during the superficial melting of the seed body and the cooling is turned on at substantially the same time as the relative movement between the cooling body and the cold-wall crucible, whereby, due to the coarsely crystalline to monocrystalline crystal structure of the seed body an axially parallel corresponding crystal structure is forced upon the ingot being built up which consists of monocrystalline to columnar crystals of large cross section and diameter.