Patent US6495890B1 successfully refreshed from Google Patents.
US6495890B1
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US
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Field-effect transistor with multidielectric constant gate insulation layer
Assignee: Kioxia Corp
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Filing: 2000-08-31
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Granted: 2002-12-17
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Expires: 2020-08-31
Abstract
Abstract A field-effect transistor comprises a semiconductor substrate, a gate insulation film formed selectively on the semiconductor substrate, a gate electrode formed on the gate insulation film, source/drain regions formed in surface portions of the semiconductor substrate along mutually opposed side surfaces of the gate electrode, the source/drain regions having opposed end portions located immediately below the gate electrode, each of the opposed end portions having an overlapping region which overlaps the gate electrode, and a channel region formed in a surface portion of the semiconductor substrate, which is sandwiched between the opposed source/drain regions. That portion of the gate insulation film, which is located at the overlapping region where at least one of the source/drain regions overlaps the gate electrode, has a lower dielectric constant than that portion of the gate insulation film, which is located on the channel region. Thereby, a short channel effect can be fully suppressed, and a high-speed operation can be realized.
Inventors
- 👤 Mizuki Ono
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:09
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D64/00; H10D64/60; H10D64/66; H10D64/671; H10D30/01; H10D30/021; H10D30/0221; H10D30/0223; H10D64/01; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01306; H10D64/01324; H10D64/01332; H10D64/01336; H10D64/01342; H10D64/01344; H10D64/675; H10D64/679; H10D64/68; H10D64/681; H10D64/685; H10D64/691; H10D64/693
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
204 words
A field-effect transistor comprising: a semiconductor substrate; a gate insulation film formed selectively on the semiconductor substrate; a gate electrode layer formed on the gate insulation film; a source region and a drain region formed in surface portions of the semiconductor substrate along opposed ends of the gate electrode layer, the source region and the drain region having opposed end portions located below the gate electrode layer; and a channel region formed in a surface portion of the semiconductor substrate between opposed end portions of the source region and the drain region, a portion of the gate insulation film on at least one of the opposed end portions having a dielectric constant lower than that of the gate insulation film on the channel region, and the gate insulation film on the channel region being formed of a first material, and the portion of the gate insulating film on at least one of the opposed end portions being formed of a second material having a dielectric constant lower than that of the first material, and the first material containing at least one selected from the group consisting of titanium oxide, tantalum pentoxide, zirconium oxide, hafnium oxide, lanthanum oxide, aluminum oxide, yttrium oxide and scandium oxide.
Claim 2
Dependent Claim
204 words
A field-effect transistor comprising: a semiconductor substrate; a gate insulation film formed selectively on the semiconductor substrate; a gate electrode layer formed on the gate insulation film; a source region and a drain region formed in surface portions of the semiconductor substrate along opposed ends of the gate electrode layer, the source region and the drain region having opposed end portions located below the gate electrode layer; and a channel region formed in a surface portion of the semiconductor substrate between opposed end portions of the source region and the drain region, a portion of the gate insulation film on at least one of the opposed end portions having a dielectric constant lower than that of the gate insulation film on the channel region, and the gate insulation film on the channel region being formed of a first material, and the portion of the gate insulating film on at least one of the opposed end portions being formed of a second material having a dielectric constant lower than that of the first material, and the first material containing at least one selected from the group consisting of titanium oxide, tantalum pentoxide, zirconium oxide, hafnium oxide, lanthanum oxide, aluminum oxide, yttrium oxide and scandium oxide.
Claim 3
Dependent Claim
63 words
A field-effect transistor according to claim 1 , wherein the portion of the gate insulation film on at least one of the opposed end portions of the source region and the drain region has a dielectric constant lower than that of the gate insulation film on the channel region, over an entire region in a film thickness direction of the gate insulation film.
Claim 4
Dependent Claim
37 words
A field-effect transistor according to claim 1 , wherein the first material forming the gate insulation film on the channel region extends partially from on the channel region to on the source region and the drain region.
Claim 5
Dependent Claim
182 words
A field effect transistor comprising: a semiconductor substrate; a gate insulation film formed selectively on the semiconductor substrate; a gate electrode layer formed on the gate insulation film; a source region and a drain region formed in surface portions of the semiconductor substrate along opposed ends of the gate electrode layer, the source region and the drain region having opposed end portions located below the gate electrode layer; and a channel region formed in a surface portion of the semiconductor substrate between the opposed end portions of the source region and the drain region, the gate insulation film on the channel region being formed of a first film, and a portion of the gate insulating film on at least one of the opposed end portions being formed of a second film having a dielectric constant lower than that of the first film, and the first film containing a mixed film formed of at least two selected from the group consisting of titanium oxide, silicon nitride, silicon oxynitride, tantalum pentoxide, zirconium oxide, hafnium oxide, lanthanum oxide, aluminum oxide, yttrium oxide and scandium oxide.
Claim 6
Dependent Claim
182 words
A field effect transistor comprising: a semiconductor substrate; a gate insulation film formed selectively on the semiconductor substrate; a gate electrode layer formed on the gate insulation film; a source region and a drain region formed in surface portions of the semiconductor substrate along opposed ends of the gate electrode layer, the source region and the drain region having opposed end portions located below the gate electrode layer; and a channel region formed in a surface portion of the semiconductor substrate between the opposed end portions of the source region and the drain region, the gate insulation film on the channel region being formed of a first film, and a portion of the gate insulating film on at least one of the opposed end portions being formed of a second film having a dielectric constant lower than that of the first film, and the first film containing a mixed film formed of at least two selected from the group consisting of titanium oxide, silicon nitride, silicon oxynitride, tantalum pentoxide, zirconium oxide, hafnium oxide, lanthanum oxide, aluminum oxide, yttrium oxide and scandium oxide.
Claim 7
Dependent Claim
144 words
A field-effect transistor comprising: a semiconductor substrate; a gate electrode layer formed above the semiconductor substrate; a gate insulation film formed between the gate electrode layer and the semiconductor substrate, the gate insulation film having a portion drawn back inwardly from at least one of opposed ends of the gate electrode layer, an interlayer insulation film formed on opposed side surfaces of the gate electrode layer and put in contact with the semiconductor substrate, so as to make a void together with the gate electrode layer, the gate insulation film, which is spaced apart from the interlayer insulation film, and the substrate; and a source region and a drain region formed in surface portions of the semiconductor substrate along the opposed ends of the gate electrode layer, the source region and the drain region having opposed end portions located below the gate electrode layer.
Claim 8
Dependent Claim
144 words
A field-effect transistor comprising: a semiconductor substrate; a gate electrode layer formed above the semiconductor substrate; a gate insulation film formed between the gate electrode layer and the semiconductor substrate, the gate insulation film having a portion drawn back inwardly from at least one of opposed ends of the gate electrode layer, an interlayer insulation film formed on opposed side surfaces of the gate electrode layer and put in contact with the semiconductor substrate, so as to make a void together with the gate electrode layer, the gate insulation film, which is spaced apart from the interlayer insulation film, and the substrate; and a source region and a drain region formed in surface portions of the semiconductor substrate along the opposed ends of the gate electrode layer, the source region and the drain region having opposed end portions located below the gate electrode layer.
Claim 9
Dependent Claim
36 words
A field-effect transistor according to claim 5 , wherein the void is made at a region between the gate electrode layer and one of the opposed end portions of the source region and the drain region.
Claim 10
Dependent Claim
40 words
A field-effect transistor according to claim 5 , wherein the gate insulating film contains at least one selected from the group consisting of titanium oxide, tantalum pentoxide, zirconium oxide, hafnium oxide, lanthanum oxide, aluminum oxide, yttrium oxide and scandium oxide.
Claim 11
Dependent Claim
23 words
A field-effect transistor according to claim 5 , wherein the gate insulation film has a higher dielectric constant than a silicon oxide film.
Claim 12
Dependent Claim
159 words
A field-effect transistor comprising: a semiconductor substrate; a gate electrode layer formed above the semiconductor substrate; a gate insulation film formed between the gate electrode layer and the semiconductor substrate, the gate insulation film having a portion drawn back inwardly from at least one of opposed ends of the gate electrode layer, the gate electrode layer having facets at end portions thereof which face the semiconductor substrate; an interlayer insulation film formed on opposed side surfaces of the gate electrode layer and put in contact with the semiconductor substrate, so as to make a void together with the gate electrode layer, the gate insulation film, which is spaced apart from the interlayer insulation film, and the substrate; and a source region and a drain region formed in surface portions of the semiconductor substrate along the opposed ends of the gate electrode layer, the source region and the drain region having opposed end portions located below the gate electrode layer.
Claim 13
Dependent Claim
159 words
A field-effect transistor comprising: a semiconductor substrate; a gate electrode layer formed above the semiconductor substrate; a gate insulation film formed between the gate electrode layer and the semiconductor substrate, the gate insulation film having a portion drawn back inwardly from at least one of opposed ends of the gate electrode layer, the gate electrode layer having facets at end portions thereof which face the semiconductor substrate; an interlayer insulation film formed on opposed side surfaces of the gate electrode layer and put in contact with the semiconductor substrate, so as to make a void together with the gate electrode layer, the gate insulation film, which is spaced apart from the interlayer insulation film, and the substrate; and a source region and a drain region formed in surface portions of the semiconductor substrate along the opposed ends of the gate electrode layer, the source region and the drain region having opposed end portions located below the gate electrode layer.
Claim 14
Dependent Claim
40 words
A field-effect transistor according to claim 9 , wherein said gate insulating film contains at least one selected from the group consisting of titanium oxide, tantalum pentoxide, zirconium oxide, hafnium oxide, lanthanum oxide, aluminum oxide, yttrium oxide and scandium oxide.
Claim 15
Dependent Claim
23 words
A field-effect transistor according to claim 9 , wherein the gate insulation film has a higher dielectric constant than a silicon oxide film.
Claim 16
Independent Claim
152 words
A method of fabricating a field-effect transistor, the method comprising: forming a gate electrode layer over a semiconductor substrate, with a gate insulation film interposed therebetween, using, as material of the gate insulation film, at least one selected from the group consisting of titanium oxide, tantalum pentoxide, zirconium oxide, hafnium oxide, lanthanum oxide, aluminum oxide, yttrium oxide and scandium oxide; forming a source region and a drain region in surface portions of the semiconductor substrate in a self-alignment manner with the gate electrode layer; removing a portion of the gate insulation film from at least one side of the gate insulation film, using the gate electrode layer as a mask; and forming a gate insulation film region, which has a lower dielectric constant than the gate insulation film, at a region from which the portion of the gate insulation film is removed and along a side surface of the gate electrode layer.
Claim 17
Independent Claim
152 words
A method of fabricating a field-effect transistor, the method comprising: forming a gate electrode layer over a semiconductor substrate, with a gate insulation film interposed therebetween, using, as material of the gate insulation film, at least one selected from the group consisting of titanium oxide, tantalum pentoxide, zirconium oxide, hafnium oxide, lanthanum oxide, aluminum oxide, yttrium oxide and scandium oxide; forming a source region and a drain region in surface portions of the semiconductor substrate in a self-alignment manner with the gate electrode layer; removing a portion of the gate insulation film from at least one side of the gate insulation film, using the gate electrode layer as a mask; and forming a gate insulation film region, which has a lower dielectric constant than the gate insulation film, at a region from which the portion of the gate insulation film is removed and along a side surface of the gate electrode layer.
Claim 18
Dependent Claim
92 words
A method according to claim 12 , wherein the forming of the gate insulation region with a lower dielectric constant than the gate insulation film includes forming, following the removing of the portion of the gate insulation film from at least one side of the gate insulation film, an interlayer insulation film on the semiconductor substrate so as to cover the gate electrode layer, and filling a portion of the interlayer insulation film, as the gate insulation region, in the region from which the portion of the gate insulation film is removed.
Claim 19
Dependent Claim
90 words
A method according to claim 12 , wherein the forming of the gate insulation region with a lower dielectric constant than the gate insulation film includes forming, following the removing of the portion of the gate insulation film from at least one side of the gate insulation film, an interlayer insulation film on the semiconductor substrate so as to cover the gate electrode layer, the interlayer insulation film forming a void as the gate insulation region at the region from which the portion of the gate insulation film is removed.
Claim 20
Dependent Claim
32 words
A method according to claim 12 , wherein the removing of the portion of the gate insulation film from at least one side of the gate insulation film includes using isotropic etching.
Claim 21
Independent Claim
139 words
A method of fabricating a field effect transistor comprising: forming a gate electrode layer over a semiconductor substrate, with a gate insulation film interposed therebetween; forming a source region and a drain region in surface portions of the semiconductor substrate in a self-alignment manner with the gate electrode layer; removing a portion of the gate insulation film from at least one side of the gate insulation film; and forming a gate insulation region, which has a lower dielectric constant than the gate insulation film, at a region from which the portion of the gate insulation film is a removed, the gate insulation region containing a mixed film formed of at least two selected from the group consisting of titanium oxide, silicon nitride, silicon oxynitride, tantalum pentoxide, zirconium oxide, hafnium oxide, lanthanum oxide, aluminum oxide, yttrium oxide and scandium oxide.
Claim 22
Independent Claim
139 words
A method of fabricating a field effect transistor comprising: forming a gate electrode layer over a semiconductor substrate, with a gate insulation film interposed therebetween; forming a source region and a drain region in surface portions of the semiconductor substrate in a self-alignment manner with the gate electrode layer; removing a portion of the gate insulation film from at least one side of the gate insulation film; and forming a gate insulation region, which has a lower dielectric constant than the gate insulation film, at a region from which the portion of the gate insulation film is a removed, the gate insulation region containing a mixed film formed of at least two selected from the group consisting of titanium oxide, silicon nitride, silicon oxynitride, tantalum pentoxide, zirconium oxide, hafnium oxide, lanthanum oxide, aluminum oxide, yttrium oxide and scandium oxide.
Claim 23
Independent Claim
97 words
A method of fabricating a field-effect transistor, the method comprising: forming a gate electrode layer over a semiconductor substrate, with a gate insulation film interposed therebetween; forming a semiconductor film selectively on a side surface of the gate electrode layer; forming a source region and a drain region in surface portions of the semiconductor substrate in a self-alignment manner with the gate electrode layer including the semiconductor film; and forming a gate insulation region, which has a dielectric constant lower than that of the gate insulation film, at a region between the semiconductor film and the substrate.
Claim 24
Independent Claim
97 words
A method of fabricating a field-effect transistor, the method comprising: forming a gate electrode layer over a semiconductor substrate, with a gate insulation film interposed therebetween; forming a semiconductor film selectively on a side surface of the gate electrode layer; forming a source region and a drain region in surface portions of the semiconductor substrate in a self-alignment manner with the gate electrode layer including the semiconductor film; and forming a gate insulation region, which has a dielectric constant lower than that of the gate insulation film, at a region between the semiconductor film and the substrate.
Claim 25
Dependent Claim
84 words
A method according to claim 17 , wherein the forming of the gate insulation region with a lower dielectric constant than the gate insulation film includes forming, following the forming of the semiconductor film selectively on the side surface of the gate electrode layer, an interlayer insulation film on the semiconductor substrate so as to cover the gate electrode layer, and filling a portion of the interlayer insulation film as the gate insulation region, in the region between the semiconductor film and the substrate.
Claim 26
Dependent Claim
88 words
A method according to claim 17 , wherein the forming of the gate insulation region with a dielectric constant lower than that of the gate insulation film includes forming, following the forming of the semiconductor film selectively on the side surface of the gate electrode layer, an interlayer insulation film on the semiconductor substrate so as to cover the gate electrode layer, the interlayer insulation film forming a void as the gate insulation region at a region among the gate insulation film, the semiconductor film and the substrate.
Claim 27
Dependent Claim
37 words
A method according to claim 17 , wherein the forming of the semiconductor film selectively on the side surface of the gate electrode layer includes growing a silicon layer on the gate electrode layer formed of polysilicon.
Claim 28
Dependent Claim
61 words
A method according to claim 17 , wherein the forming of the gate electrode layer over the semiconductor substrate with the gate insulation film interposed therebetween includes using, as material of the gate insulation film, at least one selected from the group consisting of titanium oxide, tantalum pentoxide, zirconium oxide, hafnium oxide, lanthanum oxide, aluminum oxide, yttrium oxide and scandium oxide.
References Cited (Backward Citations)
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