EP0921575A2
Expired / Lapsed
EP
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Semiconductor device comprising a heterostructure MIS field-effect transistor having a strained channel layer
Assignee: Panasonic Holdings Corp
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Filing: 1998-12-02
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Granted: —
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Expires: 2018-12-02
Abstract
Abstract A MISFET having extremely high mobility comprising a first silicon layer (Si layer)(12), a silicon layer containing carbon (Si 1-y C y layer)(13) and an optional, second silicon layer (Si layer)(14) stacked in this order on a silicon substrate (10). The carbon content and thickness of the Si 1-y C y layer acting as a channel layer of the MISFET are such that said Si 1-y C y layer is under tensile strain whereby the conduction and valence bands thereof are split. Therefore, charge carriers having a smaller effective mass, which have been induced by an electric field applied to an insulated gate electrode (15,16), are confined in the Si 1-y C y layer, and move in the channel direction. Furthermore, if the silicon layer containing carbon is made of Si 1-x-y Ge x C y , a structure suitable for a high-performance CMOS device can be formed. Alternatively, the silicon layers may contain a slight amount of carbon or germanium, and a Schottky gate may be provided whereby a MESFET is achieved.
Inventors
- 👤 Takeshi Takagi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 11:07
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/40; H10D30/47; H10D30/471; H10D30/475; H10D30/473; H10D30/751; H10D30/791; H10D30/798; H10D30/80; H10D30/801; H10D62/00; H10D62/80; H10D62/83; H10D62/832
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
74 words
A semiconductor device comprising a field effect
transistor on a substrate, the field effect transistor including: a first silicon layer formed on the substrate; a second silicon layer, which is formed on the first
silicon layer, contains carbon and has received a tensile
strain from the first silicon layer; and a gate electrode formed over the second silicon layer, wherein the second silicon layer functions as a channel
region of the field effect transistor.
Claim 2
Dependent Claim
29 words
The semiconductor device of Claim 1, wherein the
field effect transistor is an n-channel field effect transistor,
and wherein the second silicon layer is an n-channel
where electrons move.
Claim 3
Dependent Claim
27 words
The semiconductor device of Claim 2, wherein electrons
are confined by a heterobarrier formed between the first
and second silicon layers of the n-channel field effect transistor.
Claim 4
Dependent Claim
34 words
The semiconductor device of Claim 2, further comprising
a heavily doped layer, which is formed in the first silicon
layer in the vicinity of the second silicon layer and
contains a high-concentration n-type dopant.
Claim 5
Dependent Claim
15 words
The semiconductor device of Claim 3, wherein the second
silicon layer is a quantum well.
Claim 6
Dependent Claim
59 words
The semiconductor device of Claim 2, further comprising
a third silicon layer, which is formed on the second
silicon layer and under the gate electrode and applies a tensile
strain to the second silicon layer, wherein electrons are confined in the second silicon
layer by a potential well formed in a boundary between the
second and third silicon layers.
Claim 7
Dependent Claim
34 words
The semiconductor device of Claim 6, further comprising
a heavily doped layer, which is formed in the third silicon
layer in the vicinity of the second silicon layer and
contains a high-concentration n-type dopant.
Claim 8
Dependent Claim
66 words
The semiconductor device of Claim 2, further comprising
a third silicon layer, which is formed on the second
silicon layer and under the gate electrode and applies a tensile
strain to the second silicon layer, wherein electrons are confined in the second silicon
layer by a heterobarrier formed between the first and second
silicon layers and another heterobarrier formed between the
second and third silicon layers.
Claim 9
Dependent Claim
29 words
The semiconductor device of Claim 1, wherein the
field effect transistor is a p-channel field effect transistor,
and wherein the second silicon layer is a p-channel where
holes move.
Claim 10
Dependent Claim
27 words
The semiconductor device of Claim 9, wherein holes
are confined by a heterobarrier formed between the first and
second silicon layers of the p-channel field effect transistor.
Claim 11
Dependent Claim
34 words
The semiconductor device of Claim 9, further comprising
a heavily doped layer, which is formed in the first
silicon layer in the vicinity of the second silicon layer and
contains a high-concentration p-type dopant.
Claim 12
Dependent Claim
15 words
The semiconductor device of Claim 9, wherein the
second silicon layer is a quantum well.
Claim 13
Dependent Claim
59 words
The semiconductor device of Claim 9, further comprising
a third silicon layer, which is formed on the second
silicon layer and under the gate electrode and applies a tensile
strain to the second silicon layer, wherein holes are confined in the second silicon layer by
a potential well formed in a boundary between the second and
third silicon layers.
Claim 14
Dependent Claim
34 words
The semiconductor device of Claim 13, further comprising
a heavily doped layer, which is formed in the third
silicon layer in the vicinity of the second silicon layer and
contains a high-concentration p-type dopant.
Claim 15
Dependent Claim
67 words
The semiconductor device of Claim 9, further comprising
a third silicon layer, which is formed on the second
silicon layer and under the gate electrode and applies a tensile
strain to the second silicon layer, wherein holes are confined in the second silicon layer
defined by a heterobarrier formed between the first and second
silicon layers and another heterobarrier formed between the
second and third silicon layers.
Claim 16
Dependent Claim
17 words
The semiconductor device of Claim 1, further comprising
a gate insulating film formed under the gate electrode.
Claim 17
Dependent Claim
34 words
The semiconductor device of Claim 1, wherein the
thickness of the second silicon layer is smaller than a critical
thickness, which is determined by the composition of carbon
and above which dislocations are generated.
Claim 18
Dependent Claim
14 words
The semiconductor device of Claim 1, wherein the
second silicon layer further contains germanium.
Claim 19
Dependent Claim
100 words
The semiconductor device of Claim 1, wherein the
field effect transistor is an n-channel field effect transistor
in which the second silicon layer is an n-channel, and wherein the semiconductor device further comprises a
p-channel field effect transistor including: a fourth silicon layer formed on the substrate; a fifth silicon layer, which is formed on the fourth
silicon layer, contains carbon and has received a tensile
strain from the fourth silicon layer; and a gate electrode formed over the fifth silicon layer, the fifth silicon layer functioning as a p-channel region, whereby the semiconductor device functions as a complementary
device.
Claim 20
Dependent Claim
40 words
The semiconductor device of Claim 19, wherein carbon
contained in the second silicon layer of the n-channel field
effect transistor has an equal composition to that of carbon
contained in the fifth silicon layer of the p-channel field
effect transistor.
Claim 21
Dependent Claim
18 words
The semiconductor device of Claim 19, further comprising
a gate insulating film formed just under the gate
electrode.
Claim 22
Dependent Claim
34 words
The semiconductor device of Claim 19, wherein the
thickness of the fifth silicon layer is smaller than a critical
thickness, which is determined by the composition of carbon
and above which dislocations are generated.
Claim 23
Dependent Claim
16 words
The semiconductor device of Claim 19, wherein the
second and fifth silicon layers further contain germanium.
Claim 24
Dependent Claim
28 words
The semiconductor device of Claim 23, wherein germanium
contained in the second silicon layer has an equal composition
to that of germanium contained in the fifth silicon
layer.
References Cited (Backward Citations)
No citation records indexed.
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