EP1089344A2
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EP
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Insulated gate field effect transistor and method of fabricating the same
Assignee: Toshiba Corp
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Filing: 2000-09-13
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Granted: —
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Expires: 2020-09-13
Abstract
Abstract A field-effect transistor comprises a semiconductor substrate (101), a gate insulation film (111, 109') formed selectively on the semiconductor substrate (101), a gate electrode (106) formed on the gate insulation film (111, 109'), source/drain regions (107) formed in surface portions of the semiconductor substrate (101) along mutually opposed side surfaces of the gate electrode (106), the source/drain regions (107) having opposed end portions located immediately below the gate electrode (106), each of the opposed end portions having an overlapping region which overlaps the gate electrode (106), and a channel region (104) formed in a surface portion of the semiconductor substrate (101), which is sandwiched between the opposed source/drain regions (107). That portion (109') of the gate insulation film (111, 109'), which is located at the overlapping region where at least one of the source/drain regions (107) overlaps the gate electrode (106), has a lower dielectric constant than that portion (111) of the gate insulation film (111, 109'), which is located on the channel region (104). Thereby, a short channel effect can be fully suppressed, and a high-speed operation can be realized.
Inventors
- 👤 Ono Intellectual Property Division Mizuki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 01:24
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: 22
Claim 1
Independent Claim
174 words
A field-effect transistor characterized by
comprising: a semiconductor substrate (101); a gate insulation film (111, 109', 109, 116)
formed selectively on the semiconductor substrate
(101); a gate electrode (106) formed on the gate
insulation film; source/drain regions (107) formed in surface
portions of the semiconductor substrate (101) along
mutually opposed side surfaces of the gate electrode
(106), the source/drain regions (107) having opposed
end portions located immediately below the gate
electrode (106), each of the opposed end portions
having an overlapping region which overlaps the gate
electrode (106); and a channel region (104) formed in a surface portion
of the semiconductor substrate (101), which is
sandwiched between the opposed source/drain regions
(107), wherein that portion (109', 109, 116) of the gate
insulation film (111, 109', 109, 116), which is located
at the overlapping region where at least one of the
source/drain regions (107) overlaps the gate electrode
(106), has a lower dielectric constant than that
portion (111) of the gate insulation film (111, 109',
109, 116), which is located on the channel region (104).
Claim 2
Dependent Claim
70 words
A field-effect transistor according to claim 1,
characterized in that that portion (109', 109, 116) of
the gate insulation film (111, 109', 109, 116), which
has the lower dielectric constant, has a lower
dielectric constant than that portion (111) of the gate
insulation film (111, 109', 109, 116), which is located
on the channel region (104), over an entire region in a
film thickness direction of the gate insulation film.
Claim 3
Dependent Claim
80 words
A field-effect transistor according to claim 1,
characterized in that that portion (111) of the gate
insulation film (111, 109', 109, 116), which is located
on the channel region (104), is formed of a first
material, and at least a gate electrode end-side
portion (109', 109, 116) of said overlapping region
between at least one of the source/drain regions (107)
and the gate electrode (106) is formed of a second
material having a lower dielectric constant than the
first material.
Claim 4
Dependent Claim
48 words
A field-effect transistor according to claim 3,
characterized in that the first material forming that
portion (111) of the gate insulation film (111, 109',
109, 116) which is located on the channel region (104)
extends partially from on the channel region (104) to
on the source/drain regions (107).
Claim 5
Dependent Claim
58 words
A field-effect transistor according to
claim 3, characterized in that the first material
contains at least one selected from the group
consisting of a titanium oxide film, a silicon nitride
film, a silicon oxynitride film, a tantalum pentoxide
film, zirconium oxide film, hafnium oxide film,
lanthanum oxide film, aluminum oxide film, yttrium
oxide film and scandium oxide film.
Claim 6
Dependent Claim
50 words
A field effect transistor according to claim 3,
characterized in that the first material contains 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
190 words
A field-effect transistor characterized by
comprising: a semiconductor substrate (101, 103); a gate electrode (106, 112) formed above the
semiconductor substrate (101, 103); a gate insulation film (111) formed between the
gate electrode (106, 112) and the semiconductor
substrate (101, 103), the gate insulation film (111)
retreating from at least one of mutually opposed ends
of the gate electrode (106, 112); an interlayer insulation film (109) formed on at
least one of mutually opposed side surfaces of the gate
electrode (106, 112), that portion of the interlayer
insulation film (109), which is located on a side where
the gate insulation film (111) retreats, being put in
contact with the semiconductor substrate (103), and
creating a void (117) with the gate electrode (106,
112), the gate insulation film (111) and the substrate
(103); and source/drain regions (107) formed in surface
portions of the semiconductor substrate (103) along the
mutually opposed side surfaces of the gate electrode
(106, 112), the source/drain regions (107) having
opposed end portions located immediately below the gate
electrode (106, 112), each of the opposed end portions
having an overlapping region which overlaps the gate
electrode (106, 112).
Claim 8
Dependent Claim
30 words
A field-effect transistor according to
claim 7, characterized in that the void (117) is
created at the overlapping region between the gate
electrode (106, 112) and the source/drain region (107).
Claim 9
Dependent Claim
28 words
A field-effect transistor according to
claim 7, characterized in that the gate electrode (106,
112) has facets (112) at end portions thereof which
face the semiconductor substrate (103).
Claim 10
Dependent Claim
42 words
A field-effect transistor according to
claim 7, characterized in that said gate insulation
film (111) contains at least one selected from the
group consisting of a titanium oxide film, a silicon
nitride film, a silicon oxynitride film and a tantalum
pentoxide film.
Claim 11
Dependent Claim
25 words
A field-effect transistor according to
claim 7, characterized in that the gate insulation film
(111) has a higher dielectric constant than a silicon
oxide film.
Claim 12
Independent Claim
110 words
A method of fabricating a field-effect
transistor, the method characterized by comprising the
steps of: forming a gate electrode (106) over a
semiconductor substrate (101, 103), with a gate
insulation film (111) interposed therebetween; forming source/drain regions (107) in surface
portions of the semiconductor substrate (101) in a
self-alignment manner with the gate electrode (106); removing a portion of the gate insulation film
(111) from at least one side of the gate insulation
film (111); and forming a gate insulation region (109, 116), which
has a lower dielectric constant than the gate
insulation film (111), at a region from which the
portion of the gate insulation film (111) is removed.
Claim 13
Dependent Claim
109 words
A method according to claim 12, characterized
in that the step of forming the gate insulation region
(109, 116) with a lower dielectric constant than the
gate insulation film (111) includes a step of forming,
following the step of removing the portion of the gate
insulation film (111) from at least one side of the
gate insulation film (111), an interlayer insulation
film (109, 116) on the semiconductor substrate (103) so
as to cover the gate electrode (106), and filling a
portion of the interlayer insulation film (109, 116),
as the gate insulation region, in the region from which
the portion of the gate insulation film (111) is
removed.
Claim 14
Dependent Claim
107 words
A method according to claim 12, characterized
in that the step of forming the gate insulation region
(109, 116) with a lower dielectric constant than the
gate insulation film (111) includes a step of forming,
following the step of removing the portion of the gate
insulation film (111) from at least one side of the
gate insulation film (111), an interlayer insulation
film (109, 116) on the semiconductor substrate so as to
cover the gate electrode (106), the interlayer
insulation film (109, 116) forming a void (117) as the
gate insulation region at the region from which the
portion of the gate insulation film (111) is removed.
Claim 15
Dependent Claim
38 words
A method according to claim 12, characterized
in that the step of removing the portion of the gate
insulation film (111) from at least one side of the
gate insulation film (111) includes a step using
isotropic etching.
Claim 16
Dependent Claim
86 words
A method according to claim 12, characterized
in that the step of forming the gate electrode (106)
over the semiconductor substrate (103) with the gate
insulation film (111) interposed includes a step of
using, as material of the gate insulation film (111),
at least one selected from the group consisting of a
titanium oxide film, a silicon nitride film, a silicon
oxynitride film, a tantalum pentoxide film, zirconium
oxide film, hafnium oxide film, lanthanum oxide film,
aluminum oxide film, yttrium oxide film and scandium
oxide film.
Claim 17
Dependent Claim
50 words
A field effect transistor according to
claim 12, characterized in that the first material
contains 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 18
Independent Claim
104 words
A method of fabricating a field-effect
transistor, the method characterized by comprising the
steps of: forming a gate electrode (106) over a
semiconductor substrate, with a gate insulation film
(111) interposed therebetween; forming a conductor film (114) selectively on a
side surface of the gate electrode (106); forming source/drain regions (107) in surface
portions of the semiconductor substrate (103) in a
self-alignment manner with the gate electrode (106)
including the conductor film (114); and forming a gate insulation region (109), which has
a lower dielectric constant than the gate insulation
film (111), at a region between the conductor film
(114) and the substrate (103).
Claim 19
Dependent Claim
97 words
A method according to claim 18, characterized
in that the step of forming the gate insulation region
(109) with a lower dielectric constant than the gate
insulation film (111) includes a step of forming,
following the step of forming the conductor film (114)
selectively on the side surface of the gate electrode
(106), an interlayer insulation film (109) on the
semiconductor substrate so as to cover the gate
electrode (106), and filling a portion of the
interlayer insulation film (109), as the gate
insulation region, in the region between the conductor
film (114) and the substrate (103).
Claim 20
Dependent Claim
101 words
A method according to claim 18, characterized
in that the step of forming the gate insulation region
with a lower dielectric constant than the gate
insulation film (111) includes a step of forming,
following the step of forming the conductor film (114)
selectively on the side surface of the gate electrode
(106), an interlayer insulation film (109) on the
semiconductor substrate (103) so as to cover the gate
electrode (106), the interlayer insulation film (109)
forming a void (117) as the gate insulation region at a
region among the gate insulation film (111), the
conductor film (114) and the substrate (103).
Claim 21
Dependent Claim
44 words
A method according to claim 18, characterized
in that the step of forming the conductor film (114)
selectively on the side surface of the gate electrode
(106) includes a step of growing a silicon layer (114)
on the gate electrode (106) formed of polysilicon.
Claim 22
Dependent Claim
69 words
A method according to claim 18, characterized
in that the step of forming the gate electrode (106)
over the semiconductor substrate (103) with the gate
insulation film (111) interposed therebetween includes
a step of using, as material of the gate insulation
film (111), at least one selected from the group
consisting of a titanium oxide film, a silicon nitride
film, a silicon oxynitride film and a tantalum
pentoxide film.
References Cited (Backward Citations)
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