Patent US6472685B2 successfully refreshed from Google Patents.
US6472685B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor device
Assignee: Panasonic Holdings Corp
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Filing: 1998-12-02
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Granted: 2002-10-29
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Expires: 2018-12-02
Abstract
Abstract A first silicon layer (Si layer), a second silicon layer (Si1Cy layer) containing carbon and a third silicon layer not containing carbon are stacked in this order on a silicon substrate. Since the lattice constant of the Si1-yCy layer is smaller than that of the Si layer, the conduction band and the valence band of the second silicon layer receive a tensile strain to be split. Electrons having a smaller effective mass, which have been induced by an electric field applied to a gate electrode, are confined in the second silicon layer, and move in the channel direction. Thus, an n-MOSFET having extremely high mobility can be obtained. Furthermore, if the second silicon layer is made of Sil-x-yGexCy, a structure suitable for a high-performance CMOS device can be formed. A high-performance field effect transistor can be provided at lower costs by using a heterojunction structure mainly composed of silicon.
Inventors
- 👤 Takeshi Takagi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:55
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: 9
Claim 1
Independent Claim
141 words
A semiconductor device comprising an n-channel and a p-channel field effect transistor on a substrate, wherein the n-channel field effect transistor includes: a first silicon layer formed on a substrate; a first SiGeC layer in which an n-channel is formed, and which is formed on the first silicon layer, contains carbon and germanium and has received a tensile strain from the first silicon layer; and a gate electrode formed over the first SiGeC layer, the p-channel field effect transistor including: a second silicon layer formed on a substrate; a second SiGeC layer in which a p-channel is formed, and which is formed on the second silicon layer, contains carbon and germanium and has received a tensile strain from the second silicon layer; and a gate electrode formed over the second SiGeC layer, wherein the semiconductor device functions as a complementary device.
Claim 2
Dependent Claim
141 words
A semiconductor device comprising an n-channel and a p-channel field effect transistor on a substrate, wherein the n-channel field effect transistor includes: a first silicon layer formed on a substrate; a first SiGeC layer in which an n-channel is formed, and which is formed on the first silicon layer, contains carbon and germanium and has received a tensile strain from the first silicon layer; and a gate electrode formed over the first SiGeC layer, the p-channel field effect transistor including: a second silicon layer formed on a substrate; a second SiGeC layer in which a p-channel is formed, and which is formed on the second silicon layer, contains carbon and germanium and has received a tensile strain from the second silicon layer; and a gate electrode formed over the second SiGeC layer, wherein the semiconductor device functions as a complementary device.
Claim 3
Dependent Claim
46 words
The semiconductor device of claim 1 , wherein electrons are confined by a heterobarrier formed between the first silicon layer and the first SiGeC layer of the n-channel field effect transistor; and holes are confined in the second SiGeC layer of the p-channel field effect transistor.
Claim 4
Dependent Claim
62 words
The semiconductor device of claim 1 , further comprising a heavily doped layer which is formed in the first silicon layer in the vicinity of the first SiGeC layer and contains a high-concentration n-type dopant; and a heavily doped layer which is formed in the second silicon layer in the vicinity of the second SiGeC layer and contains a high-concentration p-type dopant.
Claim 5
Dependent Claim
16 words
The semiconductor device of claim 2 , wherein the first SiGeC layer is a quantum well.
Claim 6
Dependent Claim
117 words
The semiconductor device of claim 1 , further comprising a third silicon layer which is formed on the first SiGeC layer and under the gate electrode and applies a tensile strain to the first SiGeC layer; and a fourth silicon layer which is formed on the second SiGeC layer and under the gate electrode and applies a tensile strain to the second SiGeC layer, wherein electrons are confined in the first SiGeC layer by a heterobarrier formed in a boundary between the first SiGeC layer and the third silicon layer, and wherein holes are confined in the second SiGeC layer by a heterobarrier formed in a boundary between the second SiGeC layer and the fourth silicon layer.
Claim 7
Dependent Claim
62 words
The semiconductor device of claim 1 , further comprising a heavily doped layer which is formed in the third silicon layer in the vicinity of the first SiGeC layer and contains a high-concentration n-type dopant; and a heavily doped layer which is formed in the fourth silicon layer in the vicinity of the second SiGeC layer and contains a high-concentration p-type dopant.
Claim 8
Dependent Claim
29 words
The semiconductor device of claim 1 , further comprising a gate insulating film formed under an n-gate electrode and a second gate insulating film formed under a p-gate electrode.
Claim 9
Dependent Claim
35 words
The semiconductor device of claim 1 , wherein the thickness of the first SiGeC layer is smaller than a critical thickness which is determined by the composition of carbon and above which dislocations are generated.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-10-28 | 2006-04-29 | 2006-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-10-28 | 2010-04-29 | 2010-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-10-28 | 2014-04-29 | 2014-10-29 | $7700.00 | Window Closed / Lapsed |