US4819043A
Expired / Lapsed
US
⏱️ 0.0 years remaining
MOSFET with reduced short channel effect
Assignee: Hitachi Ltd
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Filing: 1986-12-01
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Granted: 1989-04-04
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Expires: 2006-12-01
Abstract
Abstract An MOSFET provided with a gate insulating film formed on a semiconductor surface between a source region and a drain region, a gate electrode formed on the gate insulating film, and a channel region sandwiched between the source region and the drain region and made up of a first layer and a second layer is disclosed in which the first layer lies beneath the gate insulating film and is opposite in conductivity type to the source and drain regions, the second layer lies beneath the first layer and has the same conductivity type as the source and drain regions, and the length of the second layer between the source region and the drain region is greater than the length of the first layer between the source region and the drain region.
Inventors
- 👤 Yoshiaki Yazawa
- 👤 Yutaka Kobayashi
- 👤 Akira Fukami
- 👤 Takahiro Nagano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:19
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/601; H10D30/01; H10D30/021; H10D30/0223; H10D30/0227; H10D30/637; H10D30/67; H10D30/6704; H10D30/6713; H10D30/6715; H10D30/6757; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0165; H10D84/0167; H10D84/02; H10D84/03; H10D84/038; Y; Y10; Y10S; Y10S257/00; Y10S257/90
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
179 words
A semiconductor switching device comprising: source and drain regions each having a first conductivity type formed on a semicodnuctor substrate opposite in conductivity type to said source and drain regions; a gate insulating film formed on a semiconductor surface between said source region and said drain region; a gate electrode formed on said gate insulating film; and a semiconductor layer lying beneath said gate insulating film and sandwiched between said source region and said drain region, said semiconductor layer being made up of a first layer and a second layer, said first layer being contiguous to said gate insulating film and opposite in conductivity type to said source and drain regions, said second layer lying beneath said first layer and having the same conductivity type as said source and drain regions, the length of said second layer between said source region and said drain region being greater than the length of said first layer between said source region and said drain region, wherein said first layer has an electric potential substantially equal to an electric potential of said substrate.
Claim 2
Dependent Claim
179 words
A semiconductor switching device comprising: source and drain regions each having a first conductivity type formed on a semicodnuctor substrate opposite in conductivity type to said source and drain regions; a gate insulating film formed on a semiconductor surface between said source region and said drain region; a gate electrode formed on said gate insulating film; and a semiconductor layer lying beneath said gate insulating film and sandwiched between said source region and said drain region, said semiconductor layer being made up of a first layer and a second layer, said first layer being contiguous to said gate insulating film and opposite in conductivity type to said source and drain regions, said second layer lying beneath said first layer and having the same conductivity type as said source and drain regions, the length of said second layer between said source region and said drain region being greater than the length of said first layer between said source region and said drain region, wherein said first layer has an electric potential substantially equal to an electric potential of said substrate.
Claim 3
Dependent Claim
45 words
A semiconductor switching device according to claim 1, wherein a depletion layer due to a PN junction between said first layer and said second layer and another depletion layer due to a PN junction between said second layer and said semiconductor substrate, overlap each other.
Claim 4
Dependent Claim
205 words
A semiconductor switching device comprising: source and drain regions formed in a semiconductor material; a gate insulating film formed on a semiconductor surface between said source region and said rain region; a gate electrode formed on said gate insulating film; and a semiconductor layer lying beneath said gate insulating film and sandwiched between said source region and said drain region, said semicodnuctor layer being made up of a first layer and a second layer, said first layer being contiguous to said gate insulating film and opposite in conductivity type to said source and drain regions, said second layer lying beneath said first layer and having the same conductivity type as said source and drain regions, the length of said second layer between said source region and said drain region being greater than the length of said first layer between said source region and said drain region, wherein said source region, said drain region and said semiconductor layer are provided on an insulating material, wherein a depletion layer due to a PN junction between said first layer and said second layer is extended to said insulating material, and wherein said first layer has an electrical potential substantially equal to an electrical potential of said source region.
Claim 5
Dependent Claim
205 words
A semiconductor switching device comprising: source and drain regions formed in a semiconductor material; a gate insulating film formed on a semiconductor surface between said source region and said rain region; a gate electrode formed on said gate insulating film; and a semiconductor layer lying beneath said gate insulating film and sandwiched between said source region and said drain region, said semicodnuctor layer being made up of a first layer and a second layer, said first layer being contiguous to said gate insulating film and opposite in conductivity type to said source and drain regions, said second layer lying beneath said first layer and having the same conductivity type as said source and drain regions, the length of said second layer between said source region and said drain region being greater than the length of said first layer between said source region and said drain region, wherein said source region, said drain region and said semiconductor layer are provided on an insulating material, wherein a depletion layer due to a PN junction between said first layer and said second layer is extended to said insulating material, and wherein said first layer has an electrical potential substantially equal to an electrical potential of said source region.
Claim 6
Dependent Claim
76 words
A semiconductor switching device according to claim 1, wherein a third layer having the same conductivity type as said source and drain regions and having an impurity concentration which is intermediate between the impurity concentration of said source and drain regions and the impurity concentration of said second layer, is provided between said semiconductor layer and each of said source and drain regions, and wherein said third layer acts as a portion of said second layer.
Claim 7
Dependent Claim
63 words
A semiconductor switching device according to claim 1, wherein a third layer having the same conductivity type as said source and drain regions and having an impurity concentration which is intermediate between the impurity concentration of said source and drain regions and the impurity concentration of said second layer, is provided between said first layer and each of said source and drain regions.
Claim 8
Dependent Claim
63 words
A semiconductor switching device according to claim 1, wherein the length of said second layer between the source and drain regions is set to a predetermined length relative to the length of the first layer between the source and drain regions and to predetermined length of said gate electrode to prevent a short channel effect for the predetermined length of said gate electrode.
Claim 9
Dependent Claim
171 words
A semiconductor switching device comprising: source and drain regions each having a firs conductivity type formed on a semiconductor substrate opposite in conductivity type to said source and drain regions; a gate insulating film formed on a semiconductor surface between said source region and said drain region; a gate electrode formed on said gate insulating film; and a semiconductor layer lying beneath said gate insulating film and sandwiched between said source region and said drain region, said semiconductor layer being made up of a first layer and a second layer, said first layer being contiguous to said gate insulating film and opposite in conductivity type to said source and drain regions, said second layer lying beneath said first layer and having the same conductivity type as said source and drain regions, the length of said second layer between said source region and said drain region being greater than the length of said first layer between said source region and said drain region, wherein first layer is not isolated from said substrate.
Claim 10
Dependent Claim
171 words
A semiconductor switching device comprising: source and drain regions each having a firs conductivity type formed on a semiconductor substrate opposite in conductivity type to said source and drain regions; a gate insulating film formed on a semiconductor surface between said source region and said drain region; a gate electrode formed on said gate insulating film; and a semiconductor layer lying beneath said gate insulating film and sandwiched between said source region and said drain region, said semiconductor layer being made up of a first layer and a second layer, said first layer being contiguous to said gate insulating film and opposite in conductivity type to said source and drain regions, said second layer lying beneath said first layer and having the same conductivity type as said source and drain regions, the length of said second layer between said source region and said drain region being greater than the length of said first layer between said source region and said drain region, wherein first layer is not isolated from said substrate.
References Cited (Backward Citations)
US3283221A
Cited
US3936857A
Cited
US4000504A
Cited
GB2027992A
Cited
JPS5731177A
Cited
JPS6050960A
Cited
US4636822A
Cited
US4613882A
Cited
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