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US 7,022,591 B2Granted
Method of fabricating a polysilicon thin film
AssigneeAu Optronics Corporation
InventorMao-Yi Chang
Life of this patent
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Abstract
The present invention uses higher protrusions of an initially formed silicon layer as crystalline seeds in the subsequent crystallization step so that the newly-formed polysilicon thin film has smoother and bigger silicon grains, and has lesser density of protrusions. Furthermore, the polysilicon thin film of the present invention can be applied to form polysilicon thin film transistors or other devices.
Claims21
A method of fabricating a polysilicon thin film, comprising:
- forming a first solid phase silicon layer having a plurality of first protrusions with different heights on a substrate, wherein the maximum distance between the top of said first protrusions and the surface of said substrate is X1, and the minimum distance between the top of said first protrusions and the surface is said substrate is Y1;
- reducing the density of the first protrusions such that a portion of said first protrusions having a distance which is between the top of said first protrusions and the surface of said substrate and larger than Z1 wherein Y1<Z1<X1, is retained and becomes a plurality of silicon grains;
- and
- performing a crystallization process using said silicon grains as crystalline seeds.
1 more element
A method of fabricating a polysilicon thin film, comprising:
- forming a first polysilicon layer on a substrate, wherein said first polysilicon layer has a plurality of first protrusions with different heights, and a maximum distance between the top of said first protrusions and the surface of said substrate is X1, and the minimum distance between the top of said first protrusions and the surface of said substrate is Y1;
- forming a first amorphous silicon layer on said first polysilicon layer;
- performing a first annealing process to liquidize the first amorphous silicon layer, said first polysilicon layer and said first protrusions having a thickness of Z1 to form a plurality of second protrusions, wherein Y1<Z1<X1 and the number of said second protrusions is less than the number of said first protrusions;
- and
- performing a crystallization process using said second protrusions as crystallization seeds to form a second polysilicon layer.
2 more elements
A method of fabricating a polysilicon thin film, comprising:
- forming a first polysilicon layer on a substrate, wherein said first polysilicon layer has a plurality of first protrusions with different heights, and the maximum distance between the top of said first protrusions and the surface of said substrate is X2, and the minimum distance between the top of said first protrusions and the surface of said substrate is Y2;
- etching a portion of said first polysilicon layer to remove said first protrusions and said first polysilicon layer having a thickness of Z2 to form a plurality of second protrusions on said substrate, wherein Y2<Z2<X2 and the number of said second protrusions is less than the number of said first protrusions;
- forming a first amorphous silicon layer on said substrate and said second protrusions;
- and
- performing a first annealing process to crystallize to form a second polysilicon layer by using said second protrusions as crystalline seeds.
2 more elements
Dependencies are inferred from the claim text.