US5324969A
Expired / Lapsed
US
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High-breakdown voltage field-effect transistor
Assignee: Sanyo Electric Co Ltd
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Filing: 1992-08-12
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Granted: 1994-06-28
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Expires: 2012-08-12
Abstract
Abstract A field-effect transistor including a first channel layer, formed in contacting relationship with a gate electrode, and a second channel layer, formed on one side or both sides of the first channel layer in non-contacting relationship with the gate electrode, the carrier concentration in the second channel layer being higher than that in the first channel layer but lower than that in high-impurity concentration active layers forming drain and source regions. The field-effect transistor employs an offset gate configuration in which the gate electrode is formed in contacting relationship with the first channel layer at a position nearer to the high-impurity concentration active layer forming the source region than to the high-impurity concentration active layer forming the drain region. A dummy gate is formed and ion implantation is performed from two different angles using the dummy gate as a mask, thereby efficiently forming the source region, drain region, and second channel layer in a sequence of successive processing steps. By combining the suitably patterned first and second ion shielding layers, the gate to source electrode spacing and the gate to drain electrode spacing are controlled by the accuracy to which the second ion shielding layer can be formed.
Inventors
- 👤 Shigeyuki Murai
- 👤 Takayoshi Higashino
- 👤 Masao Nishida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:47
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/061; H10D30/0612; H10D30/0614; H10D30/80; H10D30/87; H10D62/00; H10D62/10; H10D62/17; H10D62/213; H10D62/221; H10D64/00; H10D64/01; H10D64/012; H10D64/0124; H10D64/0125
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
184 words
A field-effect transistor, comprising: a semiconductor substrate; a gate electrode; a drain region of a first high carrier concentration of a first conductivity type; said drain region being in said substrate; a source region of a second high carrier concentration of a first conductivity type; said source region being in said substrate; a first channel layer, interposed between said drain region and said source region, contacting said gate electrode, and having a first carrier concentration of said first conductivity type; a second channel layer interposed between said first channel layer and said drain region in a non-contacting relationship with said gate electrode and having a second carrier concentration of said first conductivity type higher than said first carrier concentration of said first channel layer; said first channel layer having a thickness W1; said second channel layer having a thickness W2 satifying the expression W2≦(ε.sub.r ·ε.sub.0 ·E.sub.a)/(q·N) where ε r =relative permitivity of said second channel layer, ε 0 =permitivity of free space, E a =critical field strength at said second channel layer, q=unit charge of electron, N=carrier concentration of said second channel layer, W2<W1.
Claim 2
Dependent Claim
184 words
A field-effect transistor, comprising: a semiconductor substrate; a gate electrode; a drain region of a first high carrier concentration of a first conductivity type; said drain region being in said substrate; a source region of a second high carrier concentration of a first conductivity type; said source region being in said substrate; a first channel layer, interposed between said drain region and said source region, contacting said gate electrode, and having a first carrier concentration of said first conductivity type; a second channel layer interposed between said first channel layer and said drain region in a non-contacting relationship with said gate electrode and having a second carrier concentration of said first conductivity type higher than said first carrier concentration of said first channel layer; said first channel layer having a thickness W1; said second channel layer having a thickness W2 satifying the expression W2≦(ε.sub.r ·ε.sub.0 ·E.sub.a)/(q·N) where ε r =relative permitivity of said second channel layer, ε 0 =permitivity of free space, E a =critical field strength at said second channel layer, q=unit charge of electron, N=carrier concentration of said second channel layer, W2<W1.
Claim 3
Dependent Claim
186 words
A field-effect transistor, comprising: a gate electrode; a semiconductor substrate; a drain region of a first high carrier concentration of a first conductivity type; said drain region being in said substrate; a source region of a second high carrier concentration of a first conductivity type; said source region being in said substrate; a first channel layer, interposed between said source and said drain regions, in a contacting relationship with said gate electrode, said gate electrode having a position being nearer to said source region than to said drain region; and a second channel layer, interposed between said first channel layer and said drain region, in a non-contacting relationship with said gate electrode and having a carrier concentration higher than that in said first channel layer; said first channel layer having a thicknes W1; and said second channel layer having a thickness W2 satisfying the expression W2≦(ε.sub.r ·ε.sub.0 ·E.sub.a)/(q·N) where ε r =relative permitivity of said second channel layer, ε 0 =permitivity of free space, E a =critical field strength at said second channel layer, q=unit charge of electron, N=carrier concentration of said second channel layer, W2<W1.
Claim 4
Dependent Claim
186 words
A field-effect transistor, comprising: a gate electrode; a semiconductor substrate; a drain region of a first high carrier concentration of a first conductivity type; said drain region being in said substrate; a source region of a second high carrier concentration of a first conductivity type; said source region being in said substrate; a first channel layer, interposed between said source and said drain regions, in a contacting relationship with said gate electrode, said gate electrode having a position being nearer to said source region than to said drain region; and a second channel layer, interposed between said first channel layer and said drain region, in a non-contacting relationship with said gate electrode and having a carrier concentration higher than that in said first channel layer; said first channel layer having a thicknes W1; and said second channel layer having a thickness W2 satisfying the expression W2≦(ε.sub.r ·ε.sub.0 ·E.sub.a)/(q·N) where ε r =relative permitivity of said second channel layer, ε 0 =permitivity of free space, E a =critical field strength at said second channel layer, q=unit charge of electron, N=carrier concentration of said second channel layer, W2<W1.
Claim 5
Dependent Claim
207 words
A field-effect transistor, comprising: a semiconductor substrate; a gate electrode; a drain region of a first high carrier concentration of a first conductivity type; said drain region being in said substrate; a source region of a second high carrier concentration of a first conductivity type; said source region being in said substrate; a first channel layer, interposed between said drain region and said source region, contacting said gate electrode, and having a first carrier concentration of said first conductivity type; second channel layers including one of said second channel layers being interposed between said first channel layer and said drain region, and another of said second channel layers being interposed between said first channel layer and said source region; said second channel layers being in a non-contacting relationship with said gate electrode and having a second carrier concentration of said first conductivity type higher than said first carrier concentration of said first channel layer; and said second channel layers each having a thickness W2 satisfying the expression W2≦(ε.sub.r ·ε.sub.0 ·E.sub.a)/(q·N) where ε r =relative permitivity of said second channel layer ε 0 =permitivity of free space E a =critical field strength at said second channel layer q=unit charge of electron N=carrier concentration of said second channel layer.
Claim 6
Dependent Claim
207 words
A field-effect transistor, comprising: a semiconductor substrate; a gate electrode; a drain region of a first high carrier concentration of a first conductivity type; said drain region being in said substrate; a source region of a second high carrier concentration of a first conductivity type; said source region being in said substrate; a first channel layer, interposed between said drain region and said source region, contacting said gate electrode, and having a first carrier concentration of said first conductivity type; second channel layers including one of said second channel layers being interposed between said first channel layer and said drain region, and another of said second channel layers being interposed between said first channel layer and said source region; said second channel layers being in a non-contacting relationship with said gate electrode and having a second carrier concentration of said first conductivity type higher than said first carrier concentration of said first channel layer; and said second channel layers each having a thickness W2 satisfying the expression W2≦(ε.sub.r ·ε.sub.0 ·E.sub.a)/(q·N) where ε r =relative permitivity of said second channel layer ε 0 =permitivity of free space E a =critical field strength at said second channel layer q=unit charge of electron N=carrier concentration of said second channel layer.
Claim 7
Dependent Claim
35 words
A field-effect transistor as set forth in claim 3, wherein said second carrier concentration in said second channel layers is lower than said first and second high carrier concentrations of said drain and source regions.
Claim 8
Dependent Claim
20 words
A field-effect transistor as set forth in claim 3, comprising said first channel layer having a thickness W1 where W2≦W1.
Claim 9
Dependent Claim
34 words
A field-effect transistor as set forth in claim 3, wherein a distance between said gate electrode and said drain region is substantially equal to the distance between said gate electrode and said source region.
Claim 10
Dependent Claim
236 words
A field-effect transistor, comprising: a semiconductor substrate; a gate electrode; a drain region of a first high carrier concentration of a first conductivity type; said drain region being in said substrate; a source region of a second high carrier concentration of a first conductivity type; said source region being in said substrate; a first channel layer, interposed between said drain region and said source region, contacting said gate electrode, and having a first carrier concentration of said first conductivity type; a second channel layers interposed between said first channel layer and said drain region, and said first channel layer and said source region; said second channel layers being in a non-contacting relationship with said gate electrode and having a second carrier concentration of said first conductivity type higher than said first carrier concentration of said first channel layer; said second carrier concentration being less than said first and said second high carrier concentrations of said source and said drain regions; said first channel layer having a thickness W1; said second channel layers each having a thickness W2 satisfying the expression W2≦(ε.sub.r ·ε.sub.0 ·E.sub.a)/(q·N) where ε r =relative permitivity of said second channel layer, ε.sub. = permitivity of free space, E a =critical field strength at said second channel layer, q=unit charge of electron, N=carrier concentration of said second channel layer, W2≦W1; and said gate electrode being positioned substantially equidistant from said source and said drain region.
Claim 11
Dependent Claim
236 words
A field-effect transistor, comprising: a semiconductor substrate; a gate electrode; a drain region of a first high carrier concentration of a first conductivity type; said drain region being in said substrate; a source region of a second high carrier concentration of a first conductivity type; said source region being in said substrate; a first channel layer, interposed between said drain region and said source region, contacting said gate electrode, and having a first carrier concentration of said first conductivity type; a second channel layers interposed between said first channel layer and said drain region, and said first channel layer and said source region; said second channel layers being in a non-contacting relationship with said gate electrode and having a second carrier concentration of said first conductivity type higher than said first carrier concentration of said first channel layer; said second carrier concentration being less than said first and said second high carrier concentrations of said source and said drain regions; said first channel layer having a thickness W1; said second channel layers each having a thickness W2 satisfying the expression W2≦(ε.sub.r ·ε.sub.0 ·E.sub.a)/(q·N) where ε r =relative permitivity of said second channel layer, ε.sub. = permitivity of free space, E a =critical field strength at said second channel layer, q=unit charge of electron, N=carrier concentration of said second channel layer, W2≦W1; and said gate electrode being positioned substantially equidistant from said source and said drain region.
Claim 12
Dependent Claim
16 words
A field-effect transistor as set forth in claim 7, wherein said semiconductor substrate comprises gallium arsenide.
Claim 13
Dependent Claim
52 words
A field-effect transistor as set forth in claim 7, comprising: first insulating layers formed of a SiN film; second insulating layers formed of a SiO 2 film; and said first and second insulating layers separating said gate electrode from each of said second channel layer, said drain region, and said source region.
Claim 14
Dependent Claim
16 words
A field-effect transistor as set forth in claim 1, wherein said semiconductor substrate comprises gallium arsenide.
Claim 15
Dependent Claim
52 words
A field-effect transistor as set forth in claim 1, comprising: first insulating layers formed of a SiN film; second insulating layers formed of a SiO 2 film; and said first and second insulating layers separating said gate electrode from each of said second channel layer, said drain region, and said source region.
Claim 16
Dependent Claim
16 words
A field-effect transistor as set forth in claim 3, wherein said semiconductor substrate comprises gallium arsenide.
Claim 17
Dependent Claim
52 words
A field-effect transistor as set forth in claim 3, comprising: first insulating layers formed of a SiN film; second insulating layers formed of a SiO 2 film; and said first and second insulating layers separating said gate electrode from each of said second channel layer, said drain region, and said source region.
References Cited (Backward Citations)
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