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Title: Polycrystalline semiconductor processing

Patent ·
OSTI ID:7256468

A process is described for forming large-grain polycrystalline films from amorphous films for use as photovoltaic devices. The process operates on the amorphous film and uses the driving force inherent to the transition from the amorphous state to the crystalline state as the force which drives the grain growth process. The resultant polycrystalline film is characterized by a grain size that is greater than the thickness of the film. A thin amorphous film is deposited on a substrate. The formation of a plurality of crystalline embryos is induced in the amorphous film at predetermined spaced apart locations and nucleation is inhibited elsewhere in the film. The crystalline embryos are caused to grow in the amorphous film, without further nucleation occurring in the film, until the growth of the embryos is halted by impingement on adjacently growing embryos. The process is applicable to both batch and continuous processing techniques. In either type of process, the thin amorphous film is sequentially doped with p and n type dopants. Doping is effected either before or after the formation and growth of the crystalline embryos in the amorphous film, or during a continuously proceeding crystallization step. 10 figs.

Research Organization:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
DOE Contract Number:
FG02-79ET00081
Assignee:
Massachusetts Inst. of Tech., Cambridge, MA (United States)
Patent Number(s):
US 4379020; A
Application Number:
PPN: US 6-311850
OSTI ID:
7256468
Resource Relation:
Patent File Date: 16 Oct 1981
Country of Publication:
United States
Language:
English