US6107213A
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Method for making thin film semiconductor
Assignee: Sony Corp
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Filing: 1997-03-14
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Granted: 2000-08-22
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Expires: 2017-03-14
Abstract
Abstract The present invention provides new and improved methods for making crystalline semiconductor thin films which may be bonded to different kinds of substrates. The thin films may be flexible. In accordance with preferred methods, a multi-layer porous structure including two or more porous layers having different porosities is formed in a semiconductor substrate. A semiconductor thin film is grown on the porous structure. Electrodes and/or a desired support substrate may be attached to the grown film. The grown film is separated from the semiconductor substrate along a line of weakness defined in the porous structure. The separated thin film attached to the support substrate may be further processed to provide improved film products, solar panels and light emitting diode devices. These thin film semiconductors are excellent in crystallinity and may be inexpensively produced, thereby enabling production of solar cells and light emitting diodes at lower cost.
Inventors
- 👤 Hiroshi Tayanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:06
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/822; H10H20/826; H10H20/8264; H10F; H10F10/00; H10F10/10; H10F10/17; H10F10/174; H10F19/00; H10F19/80; H10F19/85; H10F71/00; H10F71/121; H10F71/139; H10F77/00; H10F77/10; H10F77/16; H10F77/169; H10F77/1692; H10F77/20; H10F77/206; H10F77/211; H10H20/01; H10H20/011; H10H20/014; H10P; H10P14/00; H10P14/20; H10P14/29; H10P14/2901; H10P14/2902; H10P14/2905; H10P14/32; H10P14/3202; H10P14/3204; H10P14/3211; H10P14/3238; H10P14/3242; H10P14/3256; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3411; H10P14/36; H10P14/38; H10P50/00; H10P50/60; H10P50/61; H10P50/613; H10P72/00; H10P72/70; H10P72/74; H10P90/00; H10P90/19; H10P90/1904; H10P90/1906; H10P90/1914; H10P90/1924; H10W; H10W10/00; H10W10/10; H10W10/181; H10P72/7412; H10P72/7426; H10P72/743; H10P72/7432; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/547; Y02P; Y02P70/00; Y02P70/50; Y10; Y10S; Y10S438/00; Y10S438/928; Y10S438/96; Y10S438/977
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
104 words
A method for making a thin film semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; anodizing the semi-conductor substrate to provide a first porous layer adjacent the surface having a first porosity; anodizing the semi-conductor substrate to provide at least one second porous layer adjacent the first porous layer opposite the surface, each said second porous layer having a second porosity greater than said first porosity; forming a semi-conductor film on the first porous layer; and separating the semi-conductor film from the semi-conductor substrate along a line of relative weakness defined in or adjacent one of said second porous layers.
Claim 2
Independent Claim
104 words
A method for making a thin film semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; anodizing the semi-conductor substrate to provide a first porous layer adjacent the surface having a first porosity; anodizing the semi-conductor substrate to provide at least one second porous layer adjacent the first porous layer opposite the surface, each said second porous layer having a second porosity greater than said first porosity; forming a semi-conductor film on the first porous layer; and separating the semi-conductor film from the semi-conductor substrate along a line of relative weakness defined in or adjacent one of said second porous layers.
Claim 3
Independent Claim
175 words
A method for making a thin film semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; anodizing the semi-conductor substrate at a first current density to provide a first porous layer adjacent the surface having a first porosity; anodizing the semi-conductor substrate at a second current density higher than said first current density to provide a second porous layer adjacent the first porous layer opposite the surface, the second porous layer having a second porosity greater than the first porosity; anodizing the semi-conductor substrate at a third current density higher than said second current density to provide a third porous layer in or adjacent the second porous layer, the third porous layer having a third porosity higher than said second porosity; forming at least one semi-conductor film on the surface and first porous layer; and separating the semi-conductor film from the semi-conductor substrate along a line of relative weakness defined in the third porous layer or at or adjacent an interface defined between said third porous layer and the second porous layer.
Claim 4
Independent Claim
175 words
A method for making a thin film semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; anodizing the semi-conductor substrate at a first current density to provide a first porous layer adjacent the surface having a first porosity; anodizing the semi-conductor substrate at a second current density higher than said first current density to provide a second porous layer adjacent the first porous layer opposite the surface, the second porous layer having a second porosity greater than the first porosity; anodizing the semi-conductor substrate at a third current density higher than said second current density to provide a third porous layer in or adjacent the second porous layer, the third porous layer having a third porosity higher than said second porosity; forming at least one semi-conductor film on the surface and first porous layer; and separating the semi-conductor film from the semi-conductor substrate along a line of relative weakness defined in the third porous layer or at or adjacent an interface defined between said third porous layer and the second porous layer.
Claim 5
Dependent Claim
37 words
A method as defined in claim 2, wherein in said anodizing steps, the semi-conductor substrate is contacted by an electrolytic solution and exposed to a flow of current at said first, second and third current density, respectively.
Claim 6
Dependent Claim
18 words
A method as defined in claim 3, wherein the electrolytic solution comprises hydrogen fluoride and a hydrocarbon alcohol.
Claim 7
Dependent Claim
26 words
A method as defined in claim 3, wherein in the anodizing steps, the composition of the electrolytic solution used in each anodizing step is the same.
Claim 8
Dependent Claim
24 words
A method as defined in claim 3, wherein in the anodizing steps, the composition of the electrolytic solution used in the anodizing steps varies.
Claim 9
Dependent Claim
30 words
A method as defined in claim 2, further comprising the step of annealing the semi-conductor substrate in a hydrogen atmosphere after the third anodizing step and before the forming step.
Claim 10
Dependent Claim
27 words
A method as defined in claim 7, further comprising the step of oxidizing the anodized substrate after the third anodizing step and before the hydrogen annealing step.
Claim 11
Dependent Claim
18 words
A method as defined in claim 2, wherein in the forming step the semi-conductor film is epitaxially grown.
Claim 12
Dependent Claim
17 words
A method as defined in claim 2, wherein the semi-conductor substrate is a single crystal silicon substrate.
Claim 13
Dependent Claim
16 words
A method as defined in claim 2, wherein the semi-conductor substrate is an impurity-doped semi-conductor substrate.
Claim 14
Dependent Claim
16 words
A method as defined in claim 2, wherein the semi-conductor substrate is a compound semi-conductor substrate.
Claim 15
Dependent Claim
29 words
A method as defined in claim 2, further comprising the step of attaching a support substrate to the semi-conductor film after the forming step and before the separating step.
Claim 16
Dependent Claim
15 words
A method as defined in claim 13, wherein the support substrate is a rigid substrate.
Claim 17
Dependent Claim
15 words
A method as defined in claim 13, wherein the support substrate is a flexible substrate.
Claim 18
Dependent Claim
20 words
A method as defined in claim 13, wherein the support substrate is attached to the semi-conductor film by adhesive bonding.
Claim 19
Independent Claim
217 words
A method for making a thin film semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; anodizing the semi-conductor substrate at a first current density to provide a first porous layer adjacent the surface having a first porosity; anodizing the semi-conductor substrate at a second current density higher than said first current density to provide a second porous layer adjacent the first porous layer opposite the surface, the second porous layer having a second porosity greater than the first porosity; anodizing the semi-conductor substrate at a third current density higher than said second current density to provide a third porous layer in or adjacent the second porous layer, the third porous layer having a third porosity higher than said second porosity; forming at least one semi-conductor film on the surface and first porous layer; and separating the semi-conductor film from the semi-conductor substrate along a line of relative weakness defined in the third porous layer or at or adjacent an interface defined between said third porous layer and the second porous layer, wherein in said anodizing steps, the semi-conductor substrate is contacted by an electrolytic solution and exposed to a flow of current at said first, second and third current density, respectively, and wherein in the anodizing steps, the electrolytic solution is the same.
Claim 20
Independent Claim
217 words
A method for making a thin film semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; anodizing the semi-conductor substrate at a first current density to provide a first porous layer adjacent the surface having a first porosity; anodizing the semi-conductor substrate at a second current density higher than said first current density to provide a second porous layer adjacent the first porous layer opposite the surface, the second porous layer having a second porosity greater than the first porosity; anodizing the semi-conductor substrate at a third current density higher than said second current density to provide a third porous layer in or adjacent the second porous layer, the third porous layer having a third porosity higher than said second porosity; forming at least one semi-conductor film on the surface and first porous layer; and separating the semi-conductor film from the semi-conductor substrate along a line of relative weakness defined in the third porous layer or at or adjacent an interface defined between said third porous layer and the second porous layer, wherein in said anodizing steps, the semi-conductor substrate is contacted by an electrolytic solution and exposed to a flow of current at said first, second and third current density, respectively, and wherein in the anodizing steps, the electrolytic solution is the same.
Claim 21
Independent Claim
216 words
A method for making a thin film semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; anodizing the semi-conductor substrate at a first current density to provide a first porous layer adjacent the surface having a first porosity; anodizing the semi-conductor substrate at a second current density higher than said first current density to provide a second porous layer adjacent the first porous layer opposite the surface, the second porous layer having a second porosity greater than the first porosity; anodizing the semi-conductor substrate at a third current density higher than said second current density to provide a third porous layer in or adjacent the second porous layer, the third porous layer having a third porosity higher than said second porosity; forming at least one semi-conductor film on the surface and first porous layer; and separating the semi-conductor film from the semi-conductor substrate along a line of relative weakness defined in the third porous layer or at or adjacent an interface defined between said third porous layer and the second porous layer, wherein in said anodizing steps, the semi-conductor substrate is contacted by an electrolytic solution and exposed to a flow of current at said first, second and third current density, respectively, and wherein the electrolytic solution used in the anodizing steps varies.
Claim 22
Independent Claim
216 words
A method for making a thin film semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; anodizing the semi-conductor substrate at a first current density to provide a first porous layer adjacent the surface having a first porosity; anodizing the semi-conductor substrate at a second current density higher than said first current density to provide a second porous layer adjacent the first porous layer opposite the surface, the second porous layer having a second porosity greater than the first porosity; anodizing the semi-conductor substrate at a third current density higher than said second current density to provide a third porous layer in or adjacent the second porous layer, the third porous layer having a third porosity higher than said second porosity; forming at least one semi-conductor film on the surface and first porous layer; and separating the semi-conductor film from the semi-conductor substrate along a line of relative weakness defined in the third porous layer or at or adjacent an interface defined between said third porous layer and the second porous layer, wherein in said anodizing steps, the semi-conductor substrate is contacted by an electrolytic solution and exposed to a flow of current at said first, second and third current density, respectively, and wherein the electrolytic solution used in the anodizing steps varies.
Claim 23
Independent Claim
115 words
A method for making a thin filn semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; anodizing said semi-conductor substrate at a first current density to provide a first porous layer adjacent said surface having a first porosity; anodizing said semi-conductor substrate at a second current density higher than said first current density to provide a second porous layer adjacent said first porous layer opposite said surface, said second porous layer having a second porosity greater than said first porosity; annealing said semi-conductor substrate in a hydrogen atmosphere after said step of anodizing said semi-conductor substrate to provide said second porous layer; and forming at least one semi-conductor film on said surface.
Claim 24
Independent Claim
115 words
A method for making a thin filn semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; anodizing said semi-conductor substrate at a first current density to provide a first porous layer adjacent said surface having a first porosity; anodizing said semi-conductor substrate at a second current density higher than said first current density to provide a second porous layer adjacent said first porous layer opposite said surface, said second porous layer having a second porosity greater than said first porosity; annealing said semi-conductor substrate in a hydrogen atmosphere after said step of anodizing said semi-conductor substrate to provide said second porous layer; and forming at least one semi-conductor film on said surface.
Claim 25
Independent Claim
68 words
A method for making a thin film semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; forming a first porous layer adjacent said surface having a first porosity; forming a second porous layer within said first porous layer having a second porosity higher than said first porosity; forming at least one semi-conductor film on said surface; and separating said semi-conductor film from said semi-conductor substrate.
Claim 26
Independent Claim
68 words
A method for making a thin film semi-conductor comprising the steps of: providing a semi-conductor substrate having a surface; forming a first porous layer adjacent said surface having a first porosity; forming a second porous layer within said first porous layer having a second porosity higher than said first porosity; forming at least one semi-conductor film on said surface; and separating said semi-conductor film from said semi-conductor substrate.
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