US5804473A
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Thin film semiconductor device having a polycrystal active region and a fabrication process thereof
Assignee: Sharp Corp
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Filing: 1996-09-24
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Granted: 1998-09-08
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Expires: 2016-09-24
Abstract
Abstract A method for fabricating a thin film semiconductor device includes the steps of introducing, into an amorphous film of a semiconductor material, at least one metallic element that forms an intermetallic compound with the semiconductor material and at least one nonmetallic element selected from group VIa elements, group VIIa elements or nitrogen, and crystallizing the amorphous film, after introducing the metallic element and the nonmetallic element, by a thermal annealing process, to convert the amorphous film to a crystalline film.
Inventors
- 👤 Yutaka Takizawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:21
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/20; H10P14/24; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/031; H10D30/0312; H10D30/0314; H10D30/0316; H10D30/0321; H10P14/29; H10P14/2901; H10P14/2922; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3411; H10P14/3438; H10P14/3441; H10P14/3442; H10P14/3444; H10P14/3451; H10P14/3452; H10P14/3456; H10P14/38; H10P14/3802; H10P14/3806; Y; Y10; Y10S; Y10S148/00; Y10S148/016
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
130 words
A method for fabricating a thin film semiconductor device, comprising the steps of: introducing, into an amorphous film of a semiconductor material, at least one metallic element that forms a compound with said semiconductor material and at least one nonmetallic element, said nonmetallic element being selected from the group Via elements, group VIIa elements or nitrogen; crystallizing said amorphous film, after introducing said metallic element and said nonmetallic element therein, by a thermal annealing process, to convert said amorphous film to a crystalline film; and cooling said crystalline film, said cooling process including a step of annealing said crystalline film at a temperature lower than a temperature used in said crystallizing step to form a compound comprising the at least one metallic element and the at least one non-metallic element.
Claim 2
Independent Claim
130 words
A method for fabricating a thin film semiconductor device, comprising the steps of: introducing, into an amorphous film of a semiconductor material, at least one metallic element that forms a compound with said semiconductor material and at least one nonmetallic element, said nonmetallic element being selected from the group Via elements, group VIIa elements or nitrogen; crystallizing said amorphous film, after introducing said metallic element and said nonmetallic element therein, by a thermal annealing process, to convert said amorphous film to a crystalline film; and cooling said crystalline film, said cooling process including a step of annealing said crystalline film at a temperature lower than a temperature used in said crystallizing step to form a compound comprising the at least one metallic element and the at least one non-metallic element.
Claim 3
Dependent Claim
24 words
A method as claimed in claim 1, wherein said nonmetallic element is selected from a group consisting of O, S, Cl, F and N.
Claim 4
Dependent Claim
66 words
A method as claimed in claim 1, wherein said step of introducing at least one metallic element includes a step of introducing first and second metallic elements to said amorphous film, and wherein said step of crystallizing said amorphous film includes a step of annealing said amorphous film in the state that said amorphous film contains said first and second metallic elements and said nonmetallic element.
Claim 5
Dependent Claim
48 words
A method as claimed in claim 3, wherein said first and second metallic elements comprise Ni and Pt, said nonmetallic element contains oxygen, and wherein said cooling process is conducted such that said crystalline film contains PtNiO as a product of a reaction between Ni, Pt and oxygen.
Claim 6
Dependent Claim
49 words
A method as claimed in claim 3, wherein said first and second metallic elements comprise Ni and Au, said nonmetallic element contains oxygen, and wherein said thermal annealing process is conducted such that said crystalline film contains AuNiO as a product of a reaction between Ni, Au and oxygen.
Claim 7
Dependent Claim
38 words
A method as claimed in claim 3, wherein said first and second metallic elements are selected from a group consisting of B, Al, Fe, Co, Ni, Mo, Ag, In, Sn, Hf, W, Pt, Au, Pb, Pd and Bi.
Claim 8
Dependent Claim
68 words
A thin film semiconductor device, comprising: a support substrate of an insulating material; a crystalline silicon film formed on said support substrate; and an active region formed in said crystalline silicon film; wherein said crystalline silicon film contains at least one compound comprising at least one metallic element and at least one non-metallic element, said nonmetallic element being selected from group VIa elements, group VIIa elements or nitrogen.
Claim 9
Dependent Claim
68 words
A thin film semiconductor device, comprising: a support substrate of an insulating material; a crystalline silicon film formed on said support substrate; and an active region formed in said crystalline silicon film; wherein said crystalline silicon film contains at least one compound comprising at least one metallic element and at least one non-metallic element, said nonmetallic element being selected from group VIa elements, group VIIa elements or nitrogen.
Claim 10
Dependent Claim
27 words
A thin film semiconductor device as claimed in claim 7, wherein said nonmetallic element is selected from a group consisting of O, S, Cl, F and N.
Claim 11
Dependent Claim
115 words
A liquid crystal display device, comprising: a liquid crystal layer; a glass substrate confining said liquid crystal layer; a plurality of pixel electrodes formed on a first side of said glass substrate; a plurality of thin film transistors formed on said first side of said glass substrate respectively in correspondence to said plurality of pixel electrodes; each of said thin film transistors comprising: a crystalline silicon film formed on said glass substrate; and an active region formed in said crystalline silicon film; wherein said crystalline silicon film contains a compound of at least one metallic element and least one nonmetallic element, said nonmetallic element being selected from group VIa elements, group VIIa elements or nitrogen.
Claim 12
Dependent Claim
115 words
A liquid crystal display device, comprising: a liquid crystal layer; a glass substrate confining said liquid crystal layer; a plurality of pixel electrodes formed on a first side of said glass substrate; a plurality of thin film transistors formed on said first side of said glass substrate respectively in correspondence to said plurality of pixel electrodes; each of said thin film transistors comprising: a crystalline silicon film formed on said glass substrate; and an active region formed in said crystalline silicon film; wherein said crystalline silicon film contains a compound of at least one metallic element and least one nonmetallic element, said nonmetallic element being selected from group VIa elements, group VIIa elements or nitrogen.
Claim 13
Independent Claim
175 words
A method for fabricating a thin film semiconductor device, comprising the steps of: (A) depositing a semiconductor film of a semiconductor material on a substrate in the form of an amorphous semiconductor film; (B) introducing at least one metallic element that forms a compound with said semiconductor material, into said amorphous semiconductor film; (C) dispersing, after said step (B), said metallic element in said amorphous semiconductor film; (D) introducing at least one nonmetallic element selected from group VIa elements, group VIIa elements and nitrogen into said amorphous semiconductor film; (E) dispersing, after said step (D), said nonmetallic element in said amorphous semiconductor film; (F) crystallizing, after said step (C), said amorphous semiconductor film at a first temperature to convert said amorphous semiconductor film to a crystalline semiconductor film on said substrate; and (G) annealing, after said steps (D) and (F), said crystalline semiconductor film at a second temperature lower than said first temperature, said second temperature being set such that said metallic element and said nonmetallic element form a precipitate in said crystalline semiconductor film.
Claim 14
Independent Claim
175 words
A method for fabricating a thin film semiconductor device, comprising the steps of: (A) depositing a semiconductor film of a semiconductor material on a substrate in the form of an amorphous semiconductor film; (B) introducing at least one metallic element that forms a compound with said semiconductor material, into said amorphous semiconductor film; (C) dispersing, after said step (B), said metallic element in said amorphous semiconductor film; (D) introducing at least one nonmetallic element selected from group VIa elements, group VIIa elements and nitrogen into said amorphous semiconductor film; (E) dispersing, after said step (D), said nonmetallic element in said amorphous semiconductor film; (F) crystallizing, after said step (C), said amorphous semiconductor film at a first temperature to convert said amorphous semiconductor film to a crystalline semiconductor film on said substrate; and (G) annealing, after said steps (D) and (F), said crystalline semiconductor film at a second temperature lower than said first temperature, said second temperature being set such that said metallic element and said nonmetallic element form a precipitate in said crystalline semiconductor film.
Claim 15
Dependent Claim
34 words
A method as claimed in claim 10, wherein at least two of said step (A), said step (B), said step (C), said step (D), said step (E) and said step (F) are conducted concurrently.
Claim 16
Dependent Claim
28 words
A method as claimed in claim 10, wherein said step (F) is conducted by irradiating said amorphous semiconductor film with either an ultraviolet light or an infrared light.
Claim 17
Dependent Claim
30 words
A method as claimed in claim 10, wherein said steps (C) and (E) are conducted by irradiating said amorphous semiconductor film with either an ultraviolet light or an infrared light.
Claim 18
Dependent Claim
33 words
A method as claimed in claim 10, wherein said step (G) includes a step of annealing said crystalline semiconductor film at a temperature lower than the highest temperature reached throughout said steps (A)-(F).
Claim 19
Dependent Claim
54 words
A method as claimed in claim 10, wherein said step (C), said step (E) and said step (F) are conducted by causing a melting of said semiconductor film, after said at least one metallic element and said at least one nonmetallic element are introduced, and further causing a supercooling of said molten semiconductor film.
Claim 20
Dependent Claim
19 words
A method as claimed in claim 15, wherein said step (G) is conducted by annealing said supercooled semiconductor film.
Claim 21
Dependent Claim
99 words
A method as claimed in claim 10, further comprising the steps of: forming an insulation film on said crystalline semiconductor film; forming a metal film on said insulation film; patterning said insulation film and said metal film to form a gate electrode as a part of said metal film and a gate insulation film as a part of said insulation film, such that said gate insulation film is located underneath said gate electrode; and forming a source electrode and a drain electrode on said crystalline semiconductor film; wherein said step (G) is conducted after said insulation film is formed.
Claim 22
Dependent Claim
51 words
A method as claimed in claim 10, further comprising a doping step, said doping step including the steps of adding an impurity element selected from group IIIa and group Va elements to said crystalline semiconductor film and activating said impurity element; wherein said step (G) is conducted after said doping step.
Claim 23
Dependent Claim
116 words
A method as claimed in claim 10, further comprising the steps of: forming an insulation film on said crystalline semiconductor film; forming a metal film on said insulation film; patterning said insulation film and said metal film to form a gate electrode as a part of said metal film and a gate insulation film as a part of said insulation film, such that said gate insulation film is located underneath said gate electrode; and forming a source electrode and a drain electrode on said crystalline semiconductor film; wherein said step (D) includes an ion implantation process of said nonmetallic element selectively into a part of said semiconductor film while using said gate electrode as a mask.
Claim 24
Dependent Claim
69 words
A method as claimed in claim 19, wherein said step (A) and said step (B) are conducted substantially concurrently, said method further including: a first doping step conducted concurrently with said step (A) for introducing an impurity element into said amorphous silicon film; and a second doping step conducted after said step (F) for introducing said impurity element further into said crystalline semiconductor film by an ion implantation process.
References Cited (Backward Citations)
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