Patent ID: 6111191
Filing Date: 2000-08-29
Classification: H01L,Y02E,Y02P,Y10S,Y10T

Abstract:
In a process for making an improved columnar-grained polycrystalline sheet, (a) comprising applying granular silicon to a setter material which supports the granular silicon (b) preheating the setter material and granular silicon in a preheat zone, (c) subjecting the setter material and granular silicon to a thermal profile which causes melting of the granular silicon, (d) transporting the melt pool on the silicon net into a growth zone wherein a thermal profile is created to promote columnar growth, (e) transporting the grown sheet to an anneal zone, and (f) removing the polycrystalline sheet from the setter material, the improvement being in controlling nucleation of crystal growth by forming a nucleation layer against the silicon to effect heterogeneous nucleation.