Patent US5639689A successfully refreshed from Google Patents.
US5639689A
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Method for fabricating storage electrode of semiconductor device
Assignee: SK Hynix Inc
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Filing: 1994-12-28
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Granted: 1997-06-17
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Expires: 2014-12-28
Abstract
Abstract A method for fabricating a storage electrode of a semiconductor device, capable of forming the storage electrode to have a rough surface with hemispherical lugs by use of simplified deposition process and heat treatment using a single process tube to obtain a high capacitance in spite of a small cell area, thereby greatly improving the operation characteristic of the semiconductor device. The method includes the steps of bring a doped amorphous silicon film into contact with a portion of a substrate to be contact with the storage electrode, repeatedly forming an undoped amorphous silicon film and another doped amorphous silicon film over the doped amorphous silicon film at least one time, subjecting all the doped and undoped amorphous silicon films to a thermal treatment in an inert gas atmosphere for a time so that a dopant of each doped amorphous silicon film is diffused in a portion of the undoped amorphous silicon film while all the doped and undoped amorphus silicon films are crystallized into polysilicon films respectively; and etching the polysilicon films by use of a wet etch solution exhibiting an etch selectivity to an undoped one of the polysilicon film so that doped ones of the polysilicon films are etched at a higher rate than the undoped polysilicon film.
Inventors
- 👤 Sang Ho Woo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:24
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/692; H10D1/711; H10D1/712; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/922; Y10S438/964
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
199 words
A method for fabricating a storage electrode of a semiconductor memory device, comprising the steps of: bringing a doped amorphous silicon film into contact with a portion of a substrate to be in contact with the storage electrode; at least one time forming an undoped amorphous silicon film and another doped amorphous silicon film over the doped amorphous silicon film; patterning the doped and undoped amorphous silicon films; subjecting all the doped and undoped amorphous silicon films to a thermal treatment in an inert gas atmosphere so that dopants of each doped amorphous silicon film are diffused in a portion of the undoped amorphous silicon film while all the doped and undoped amorphous silicon films are crystallized into doped and undoped polysilicon films respectively wherein the thermal treatment is controlled for the dopants to be diffused into a grain boundary of the undoped polysilicon film; and selectively etching the doped polysilicon films by use of a wet etch solution, to leave remaining a portion of the doped polysilicon film in order that the undoped polysilicon film is electrically connected to the substrate, whereby the undoped polysilicon films have a rough surface while the doped polysilicon films are selectively etched.
Claim 2
Independent Claim
199 words
A method for fabricating a storage electrode of a semiconductor memory device, comprising the steps of: bringing a doped amorphous silicon film into contact with a portion of a substrate to be in contact with the storage electrode; at least one time forming an undoped amorphous silicon film and another doped amorphous silicon film over the doped amorphous silicon film; patterning the doped and undoped amorphous silicon films; subjecting all the doped and undoped amorphous silicon films to a thermal treatment in an inert gas atmosphere so that dopants of each doped amorphous silicon film are diffused in a portion of the undoped amorphous silicon film while all the doped and undoped amorphous silicon films are crystallized into doped and undoped polysilicon films respectively wherein the thermal treatment is controlled for the dopants to be diffused into a grain boundary of the undoped polysilicon film; and selectively etching the doped polysilicon films by use of a wet etch solution, to leave remaining a portion of the doped polysilicon film in order that the undoped polysilicon film is electrically connected to the substrate, whereby the undoped polysilicon films have a rough surface while the doped polysilicon films are selectively etched.
Claim 3
Dependent Claim
29 words
A method in accordance with claim 1 wherein the formation of each of the doped amorphous silicon films is carried out at a temperature of 480° to 550° C.
Claim 4
Dependent Claim
27 words
A method in accordance with claim 1, wherein the thermal treatment is carried out at a temperature of 650° to 750° C. for 30 to 60 minutes.
Claim 5
Dependent Claim
31 words
A method in accordance with claim 1, wherein the wet etch solution consists essentially of a mixture of a water with a nitric acid, an acetic acid, and a fluoric acid.
Claim 6
Dependent Claim
17 words
A method in accordance with claim 1, wherein the doped amorphous silicon film is supersaturated with dopants.
Claim 7
Dependent Claim
27 words
A method in accordance with claim 1, wherein a thickness of the doped amorphous silicon film is less than a thickness of the undoped amorphous silicon film.
Claim 8
Dependent Claim
23 words
A method in accordance with claim 1, further comprising the steps of forming a doped amorphous silicon film prior to the thermal treatment.
Claim 9
Independent Claim
198 words
A method for fabricating a storage electrode of a semiconductor memory device, comprising the steps of: bringing a doped amorphous silicon film into contact with a portion of a substrate to be in contact with the storage electrode; at least one time forming an undoped amorphous silicon film and another doped amorphous silicon film over the doped amorphous silicon film; subjecting all the doped and undoped amorphous silicon films to a thermal treatment in an inert gas atmosphere so that dopants of each doped amorphous silicon film are diffused in a portion of the undoped amorphous silicon film while all the doped and undoped amorphous silicon films are crystallized into doped and undoped polysilicon films respectively, wherein the thermal treatment is controlled for the dopants to be diffused into a grain boundary of the undoped polysilicon film; and patterning the doped and undoped polysilicon films; selectively etching the doped polysilicon films by use of a wet etch solution, to leave remaining a portion of the doped polysilicon film in order that the undoped polysilicon film is electrically connected to the substrate, whereby the undoped polysilicon film has a rough surface while the doped polysilicon film is selectively etched.
Claim 10
Independent Claim
198 words
A method for fabricating a storage electrode of a semiconductor memory device, comprising the steps of: bringing a doped amorphous silicon film into contact with a portion of a substrate to be in contact with the storage electrode; at least one time forming an undoped amorphous silicon film and another doped amorphous silicon film over the doped amorphous silicon film; subjecting all the doped and undoped amorphous silicon films to a thermal treatment in an inert gas atmosphere so that dopants of each doped amorphous silicon film are diffused in a portion of the undoped amorphous silicon film while all the doped and undoped amorphous silicon films are crystallized into doped and undoped polysilicon films respectively, wherein the thermal treatment is controlled for the dopants to be diffused into a grain boundary of the undoped polysilicon film; and patterning the doped and undoped polysilicon films; selectively etching the doped polysilicon films by use of a wet etch solution, to leave remaining a portion of the doped polysilicon film in order that the undoped polysilicon film is electrically connected to the substrate, whereby the undoped polysilicon film has a rough surface while the doped polysilicon film is selectively etched.
Claim 11
Dependent Claim
29 words
A method in accordance with claim 8, wherein the formation of each of the doped amorphous silicon films is carried out at a temperature of 480° to 550° C.
Claim 12
Dependent Claim
27 words
A method in accordance with claim 8, wherein the thermal treatment is carried out at a temperature of 650° to 750° C. for 30 to 60 minutes.
References Cited (Backward Citations)
US4143178A
Cited
US4240196A
Cited
US5164337A
Cited
US5053351A
Cited
US5281549A
Cited
US5147820A
Cited
US5298436A
Cited
US5371039A
Cited
US5350698A
Cited
US5441904A
Cited
US5478769A
Cited
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