Directional Solid Phase Crystallization of Thin Amorphous Silicon for Solar Cell Applications
First Claim
1. A method of heat treating a crystalline silicon substrate, comprising:
- depositing an amorphous silicon film on a first surface of the crystalline silicon substrate, wherein the first surface of the crystalline silicon substrate is generally opposite to a second surface; and
heating the crystalline silicon substrate and the amorphous silicon film to a temperature that is sufficient to crystallize the amorphous silicon film, wherein the heating creates a temperature gradient in which the temperature at the second surface is greater than the temperature at the first surface.
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Abstract
Embodiments of the present invention provide a method for converting a doped amorphous silicon layer deposited onto a crystalline silicon substrate into crystalline silicon having the same grain structure and crystal orientation as the underlying crystalline silicon substrate upon which the amorphous silicon was initially deposited. Additional embodiments of the present invention provide depositing a dielectric passivation layer onto the amorphous silicon layer prior to the conversion. A temperature gradient is provided at a temperature and for a time period sufficient to provide a desired p-n junction depth and dopant profile.
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Citations
22 Claims
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1. A method of heat treating a crystalline silicon substrate, comprising:
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depositing an amorphous silicon film on a first surface of the crystalline silicon substrate, wherein the first surface of the crystalline silicon substrate is generally opposite to a second surface; and heating the crystalline silicon substrate and the amorphous silicon film to a temperature that is sufficient to crystallize the amorphous silicon film, wherein the heating creates a temperature gradient in which the temperature at the second surface is greater than the temperature at the first surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 22)
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9. A method of heat treating a crystalline silicon substrate to form a p-n junction, comprising:
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depositing an amorphous silicon film on a first surface of the crystalline silicon substrate, wherein the first surface of the crystalline silicon substrate is generally opposite to a second surface; depositing a dielectric layer over the amorphous silicon film; and heating the crystalline silicon substrate and the amorphous silicon film to a temperature that is sufficient to crystallize the amorphous silicon film, wherein the heating creates a temperature gradient between the second surface and the first surface so that a temperature of the first surface is higher than a temperature of a point within the deposited amorphous silicon film that is a distance from the first surface. - View Dependent Claims (10, 11, 12, 13, 14, 15, 20, 21)
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16-19. -19. (canceled)
Specification