EP1020900A2
Expired / Lapsed
EP
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Semiconductor device and method for fabricating the same
Assignee: Panasonic Corp
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Filing: 2000-01-12
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Granted: —
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Expires: 2020-01-12
Abstract
Abstract An Si 1-y Ge y layer (where 0<y<1), an Si layer containing C, a gate insulating film and a gate electrode are formed in this order on a semiconductor substrate. An Si/SiGe heterojunction is formed between the Si and Si 1-y Ge y layers. Since C is contained in the Si layer, movement, diffusion and segregation of Ge atoms in the Si 1-y Ge y layer can be suppressed. As a result, the Si/Si 1-y Ge y interface can have its structural disorder eased and can be kept definite and planar. Thus, the mobility of carriers moving along the interface in the channel can be increased. That is to say, the thermal budget of the semiconductor device during annealing can be improved. Also, by grading the concentration profile of C, the diffusion of C into the gate insulating film can be suppressed and decline in reliability can be prevented.
Inventors
- 👤 Koichiro Yuki
- 👤 Tohru Saitoh
- 👤 Minoru Kubo
- 👤 Kiyoshi Ohnaka
- 👤 Akira Asai
- 👤 Koji Katayama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 20:19
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/80; H10P; H10P30/00; H10P30/20; H10P30/202; H10P30/204; H10D30/00; H10D30/60; H10D30/751; H10D30/791; H10D30/798; H10D62/00; H10D62/80; H10D62/82; H10D62/822; H10D62/83; H10D62/834; H10P30/208; H10P30/225
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
87 words
A semiconductor device comprising: a semiconductor substrate; a first semiconductor layer, which is formed within the
semiconductor substrate and is made of mixed crystals of multiple
elements; and a second semiconductor layer, which is formed within the
semiconductor substrate to be in contact with the first semiconductor
layer and contains an inhibitor for suppressing
movement of at least one of the constituent elements of the
first semiconductor layer, wherein the semiconductor device functions as a device
using a heterojunction formed between the first and second
semiconductor layers.
Claim 2
Dependent Claim
33 words
The device of Claim 1, wherein the first semiconductor
layer is made of Si 1-y Ge y , where 0<y<1, the second semiconductor
layer is made of Si, and the inhibitor is C.
Claim 3
Dependent Claim
14 words
The device of Claim 2, wherein the concentration of C
is 1% or less.
Claim 4
Dependent Claim
57 words
The device of Claim 2, wherein the Si layer is located
closer to the surface of the semiconductor substrate than
the Si 1-y Ge y layer is, and wherein a concentration of C in the Si layer has such a
profile as decreasing from the Si 1-y Ge y layer toward the surface
of the semiconductor substrate.
Claim 5
Dependent Claim
28 words
The device of Claim 2, wherein the Si 1-y Ge y layer has a
thickness equal to or smaller than its critical thickness, and
receives a compressive strain.
Claim 6
Dependent Claim
33 words
The device of Claim 2, which is a field effect transistor
further comprising: a gate electrode formed on the semiconductor substrate;
and a channel formed in the Si layer under the gate electrode.
Claim 7
Dependent Claim
20 words
The device of Claim 6, further comprising a gate insulating
film interposed between the gate electrode and the
Si layer.
Claim 8
Dependent Claim
21 words
The device of Claim 7, further comprising an intrinsic
Si layer interposed between the Si layer and the gate insulating
film.
Claim 9
Dependent Claim
57 words
The device of Claim 6, wherein the Si layer is located
closer to the surface of the semiconductor substrate than
the Si 1-y Ge y layer is, and wherein a concentration of C in the Si layer has such a
profile as decreasing from the Si 1-y Ge y layer toward the surface
of the semiconductor substrate.
Claim 10
Dependent Claim
176 words
The device of Claim 2, wherein the Si layer is located
closer to the surface of the semiconductor substrate
than the Si 1-y Ge y layer is, and wherein the device further comprises: a second Si layer, which is formed under the Si 1-y Ge y layer and contains C; an Si 1-x Ge x layer formed under the second Si layer, where
0<x<1; and a δ-doped layer, which is formed within the Si 1-x Ge x layer in a region thereof closer to the second Si layer and
contains a high-concentration carrier dopant, and wherein the semiconductor device is a CMOS device including: a p-channel field effect transistor, which includes a
gate electrode and a p-channel, the gate electrode being
formed on the semiconductor substrate, the p-channel being
defined in the Si 1-x Ge x layer under the gate electrode; and an n-channel field effect transistor, which includes a
gate electrode and an n-channel, the gate electrode being
formed on the semiconductor substrate, the n-channel being
defined in the Si layer under the gate electrode.
Claim 11
Dependent Claim
31 words
The device of Claim 10, wherein the Si and second Si
layers receive a tensile strain, and wherein a strain applied to the Si 1-x Ge x layer has been
relaxed.
Claim 12
Dependent Claim
28 words
The device of Claim 10, further comprising gate insulating
films formed between the gate electrodes of the p- and
n-channel field effect transistors and the Si layer, respectively.
Claim 13
Dependent Claim
29 words
The device of Claim 12, further comprising intrinsic
Si layers formed between the gate insulating films of the p- and
n-channel field effect transistors and the Si layer, respectively.
Claim 14
Dependent Claim
34 words
The device of Claim 12, wherein a concentration of C
in the Si layer has such a profile as decreasing from the
Si 1-y Ge y layer toward the surface of the semiconductor substrate.
Claim 15
Dependent Claim
35 words
The device of Claim 10, wherein a concentration of C
in the second Si layer has such a profile as decreasing from
the Si 1-x Ge x layer toward the Si 1-y Ge y layer.
Claim 16
Dependent Claim
27 words
The device of Claim 10, wherein a content of Ge in
the Si 1-y Ge y layer increases from the second Si layer toward the
Si layer.
Claim 17
Independent Claim
109 words
A method for fabricating a semiconductor device,
comprising the steps of: a) forming a first semiconductor layer, which is made of
mixed crystals of multiple elements, on a substrate; b) forming a second semiconductor layer on the first
semiconductor layer; and c) doping the first and second semiconductor layers with
an inhibitor by implanting ions of the inhibitor thereto, the
inhibitor suppressing movement of at least one of the constituent
elements of the first semiconductor layer, wherein the step c) is performed after the step b) has
been performed, and wherein the semiconductor device functions as a device
using a heterojunction formed between the first and second
semiconductor layers.
Claim 18
Dependent Claim
33 words
The method of Claim 17, wherein the first semiconductor
layer is made of Si 1-y Ge y , where 0<y<1, the second
semiconductor layer is made of Si, and the inhibitor is C.
Claim 19
Dependent Claim
56 words
The method of Claim 18, further comprising the steps
of: forming an intrinsic Si layer on the Si layer after the
step b) has been performed and before the step c) is performed;
and forming an oxide film substantially reaching the Si
layer by oxidizing the intrinsic Si layer after the step c)
has been performed.
Claim 20
Independent Claim
95 words
A method for fabricating a semiconductor device,
comprising the steps of: a) forming a first semiconductor layer, which is made of
mixed crystals of multiple elements, on a substrate; and b) forming a second semiconductor layer, which contains
an inhibitor, on the first semiconductor layer such that the
concentration of the inhibitor in the second semiconductor
layer decreases upward, the inhibitor suppressing movement of
at least one of the constituent elements of the first semiconductor
layer, wherein the semiconductor device functions as a device
using a heterojunction formed between the first and second
semiconductor layers.
Claim 21
Dependent Claim
17 words
The method of Claim 20, wherein in the step b), CVD,
UHV-CVD or MBE process is performed.
Claim 22
Dependent Claim
35 words
The method of Claim 20 or 21, wherein the first
semiconductor layer is made of Si 1-y Ge y , where 0<y<1, the second
semiconductor layer is made of Si, and the inhibitor is
C.
Claim 23
Dependent Claim
42 words
The method of Claim 22, further comprising the steps
of: forming an intrinsic Si layer on the Si layer after the
step b) has been performed; and forming an oxide film substantially reaching the Si
layer by oxidizing the intrinsic Si layer.
References Cited (Backward Citations)
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