US5096845A
Expired / Lapsed
US
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Method of making field effect transistors in an inner region of a hole
Assignee: Mitsubishi Electric Corp
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Filing: 1990-03-21
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Granted: 1992-03-17
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Expires: 2010-03-21
Abstract
Abstract A channel surface with a channel region and a gate electrode opposing to each other is formed approximately vertical to a main surface of a semiconductor substrate in the field effect transistor (FET). A p type (n type) single crystal silicon layer is formed in a hole of an insulating layer on the main surface of the substrate. N type (p type) drain and source regions are formed defining the channel region in the single crystal silicon layer. A gate electrode is formed above the channel region on the side wall of the single crystal silicon layer in the hole. The area of the main surface of the substrate occupied by one FET can be reduced in this manner. A semiconductor device can be provided in which FETs are integrated to a higher degree without degrading performance of the transistors. The method for manufacturing the semiconductor device comprises the steps of forming an insulating layer with a hole reaching to the main surface of the substrate, forming a single crystal silicon layer in the hole, forming a gate electrode on the side wall surface of the single crystal silicon layer, and forming source and drain regions in the single crystal silicon layer in selfalignment.
Inventors
- 👤 Yasuo Inoue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:06
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H10D62/149; H10D62/151; H10D30/00; H10D30/01; H10D30/021; H10D30/026; H10D30/027; H10D30/0275; H10D30/60; H10D64/00; H10D64/01; H10D64/025; H10D64/027; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0165; H10D84/02; H10D84/03; H10D84/038; H10D84/90; H10D84/903; H10D84/907; H10D84/80; H10D84/82; H10D84/83; H10D84/85; H10D84/859
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
199 words
A method for manufacturing a semiconductor device having a field effect transistor of a first conductivity type and a field effect transistor of a second conductivity type, comprising the steps of: preparing a semiconductor substrate having a main surface; forming an insulating layer on the main surface of said semiconductor substrate; forming a hole whose bottom surface is a portion of the main surface, which is exposed, of said semiconductor substrate in said insulating layer; forming a single crystal semiconductor layer on the main surface of said semiconductor substrate in said hole; forming a first single crystal semiconductor layer portion of a first conductivity type by selectively doping impurities of the first conductivity type in said single crystal semiconductor layer; forming a second single crystal semiconductor layer portion of a second conductivity type by selectively doping impurities of the second conductivity type in said single crystal semiconductor layer; forming a field effect transistor of the second conductivity type in an inner region of said hole including said first single crystal semiconductor layer portion; and forming a field effect transistor of the first conductivity type in an inner region of said hole including said second single crystal semiconductor layer portion.
Claim 2
Independent Claim
199 words
A method for manufacturing a semiconductor device having a field effect transistor of a first conductivity type and a field effect transistor of a second conductivity type, comprising the steps of: preparing a semiconductor substrate having a main surface; forming an insulating layer on the main surface of said semiconductor substrate; forming a hole whose bottom surface is a portion of the main surface, which is exposed, of said semiconductor substrate in said insulating layer; forming a single crystal semiconductor layer on the main surface of said semiconductor substrate in said hole; forming a first single crystal semiconductor layer portion of a first conductivity type by selectively doping impurities of the first conductivity type in said single crystal semiconductor layer; forming a second single crystal semiconductor layer portion of a second conductivity type by selectively doping impurities of the second conductivity type in said single crystal semiconductor layer; forming a field effect transistor of the second conductivity type in an inner region of said hole including said first single crystal semiconductor layer portion; and forming a field effect transistor of the first conductivity type in an inner region of said hole including said second single crystal semiconductor layer portion.
Claim 3
Independent Claim
249 words
A method for manufacturing a semiconductor device having field effect transistors, comprising the steps of: preparing a semiconductor substrate having a main surface; forming an insulating layer on the main surface of said semiconductor substrate; forming a hole with a bottom surface being a portion of the main surface, which is exposed, of said semiconductor substrate in said insulating layer; forming a single crystal semiconductor on the main surface of said semiconductor substrate in said hole; and forming a field effect transistor in an inner region of said hole including said single crystal semiconductor layer; wherein said step of forming the field effect transistor comprises the steps of: forming a single crystal semiconductor layer of a first conductivity type by doping impurities of the first conductivity type in said single crystal semiconductor layer; forming a hole for forming a gate electrode whose bottom surface is the main surface of said semiconductor substrate and whose side wall surface is at least said single crystal semiconductor layer, by selectively removing said single crystal semiconductor layer; forming a gate insulating layer on the side wall surface of said single crystal semiconductor layer in said hole for forming the gate electrode; forming the gate electrode on said gate insulating layer in said hole for forming the gate electrode; and forming first and second impurity regions of a second conductivity type spaced apart from each other by selectively doping impurities of the second conductivity type in a region of said single crystal semiconductor layer.
Claim 4
Independent Claim
249 words
A method for manufacturing a semiconductor device having field effect transistors, comprising the steps of: preparing a semiconductor substrate having a main surface; forming an insulating layer on the main surface of said semiconductor substrate; forming a hole with a bottom surface being a portion of the main surface, which is exposed, of said semiconductor substrate in said insulating layer; forming a single crystal semiconductor on the main surface of said semiconductor substrate in said hole; and forming a field effect transistor in an inner region of said hole including said single crystal semiconductor layer; wherein said step of forming the field effect transistor comprises the steps of: forming a single crystal semiconductor layer of a first conductivity type by doping impurities of the first conductivity type in said single crystal semiconductor layer; forming a hole for forming a gate electrode whose bottom surface is the main surface of said semiconductor substrate and whose side wall surface is at least said single crystal semiconductor layer, by selectively removing said single crystal semiconductor layer; forming a gate insulating layer on the side wall surface of said single crystal semiconductor layer in said hole for forming the gate electrode; forming the gate electrode on said gate insulating layer in said hole for forming the gate electrode; and forming first and second impurity regions of a second conductivity type spaced apart from each other by selectively doping impurities of the second conductivity type in a region of said single crystal semiconductor layer.
Claim 5
Dependent Claim
139 words
A method for manufacturing a semiconductor device having field effect transistors according to claim 2, wherein said step of forming said hole in said insulating layer comprises formation of a hole having an approximately rectangular horizontal shape in the insulating layer; said step of forming the single crystal semiconductor layer in said hole comprises formation of a single crystal semiconductor layer having a horizontal shape of approximately rectangular with one side opened; said step of forming said gate electrode comprises formation of a conductive layer buried in said hole for forming the gate electrode sandwiched by the single crystal semiconductor layer of said approximately rectangular shape with one side opened; and said step of forming said first and second impurity regions comprises formation of impurity regions on opposing end portions of said approximately rectangular shape with one side opened.
Claim 6
Dependent Claim
93 words
A method for manufacturing a semiconductor device having field effect transistors according to claim 2, wherein said step of forming said gate electrode comprises formation of the electrode portion buried in said hole for forming the gate electrode and of the contact portion extending from the electrode portion over the upper surface of said single crystal semiconductor layer with an insulating layer interposed therebetween; and said step of forming said first and second impurity regions comprises formation of the impurity regions in selfalignment using said contact portion as a portion of a mask.
Claim 7
Independent Claim
434 words
A method for manufacturing a semiconductor device having field effect transistors, comprising the steps of: preparing a semiconductor substrate having a main surface; forming an insulating layer on the main surface of said semiconductor substrate; forming a hole with a bottom surface being a portion of the main surface, which is exposed, of said semiconductor substrate in said insulating layer; forming a single crystal semiconductor on the main surface of said semiconductor substrate in said hole; forming a first single crystal semiconductor layer portion of a first conductivity type by selectively doping impurities of the first conductivity type in said single crystal semiconductor layer; forming a second single crystal semiconductor layer portion of a second conductivity type by selectively doping impurities of the second conductivity type in said single crystal semiconductor layer; forming a field effect transistor of the second conductivity type in an inner region of said hole including said first single crystal semiconductor layer portion; forming a field effect transistor of the first conductivity type in an inner region of said hole including said second single crystal semiconductor layer portion and forming a hole for forming a gate electrode whose bottom surface is the main surface of said semiconductor substrate and whose side wall surface is at least said single crystal semiconductor layer portion and said second single crystal semiconductor layer portion, by selectively removing said single crystal semiconductor layer; wherein said step of forming the field effect transistor of said second conductivity type comprises the steps of forming a first gate insulating layer on the side wall surface of said first single crystal semiconductor layer portion in said hole for forming the gate electrode, forming a first gate electrode on said first gate insulating layer in said hole for forming the gate electrode, and forming first and second impurity regions of the second conductivity type spaced apart from each other by selectively doping impurities of the second conductivity type in a region of said first single crystal semiconductor layer portion; and said step of forming the field effect transistor of said first conductivity type comprises the steps of forming a second gate insulating layer on the side wall surface of said second single crystal semiconductor layer portion in said hole for forming the gate electrode, forming a second gate electrode on said second gate insulating layer in said hole for forming the gate electrode, and forming third and fourth impurity regions of the first conductivity type spaced apart from each other by selectively doping impurities of the first conductivity type in a region of said second single crystal semiconductor layer portion.
Claim 8
Independent Claim
434 words
A method for manufacturing a semiconductor device having field effect transistors, comprising the steps of: preparing a semiconductor substrate having a main surface; forming an insulating layer on the main surface of said semiconductor substrate; forming a hole with a bottom surface being a portion of the main surface, which is exposed, of said semiconductor substrate in said insulating layer; forming a single crystal semiconductor on the main surface of said semiconductor substrate in said hole; forming a first single crystal semiconductor layer portion of a first conductivity type by selectively doping impurities of the first conductivity type in said single crystal semiconductor layer; forming a second single crystal semiconductor layer portion of a second conductivity type by selectively doping impurities of the second conductivity type in said single crystal semiconductor layer; forming a field effect transistor of the second conductivity type in an inner region of said hole including said first single crystal semiconductor layer portion; forming a field effect transistor of the first conductivity type in an inner region of said hole including said second single crystal semiconductor layer portion and forming a hole for forming a gate electrode whose bottom surface is the main surface of said semiconductor substrate and whose side wall surface is at least said single crystal semiconductor layer portion and said second single crystal semiconductor layer portion, by selectively removing said single crystal semiconductor layer; wherein said step of forming the field effect transistor of said second conductivity type comprises the steps of forming a first gate insulating layer on the side wall surface of said first single crystal semiconductor layer portion in said hole for forming the gate electrode, forming a first gate electrode on said first gate insulating layer in said hole for forming the gate electrode, and forming first and second impurity regions of the second conductivity type spaced apart from each other by selectively doping impurities of the second conductivity type in a region of said first single crystal semiconductor layer portion; and said step of forming the field effect transistor of said first conductivity type comprises the steps of forming a second gate insulating layer on the side wall surface of said second single crystal semiconductor layer portion in said hole for forming the gate electrode, forming a second gate electrode on said second gate insulating layer in said hole for forming the gate electrode, and forming third and fourth impurity regions of the first conductivity type spaced apart from each other by selectively doping impurities of the first conductivity type in a region of said second single crystal semiconductor layer portion.
Claim 9
Dependent Claim
47 words
A method for manufacturing a semiconductor device having field effect transistors according to claim 5, wherein said steps of forming said first gate electrode and said second gate electrode comprise formation of a common gate electrode in which the first and second gate electrodes are formed integrally.
Claim 10
Dependent Claim
265 words
A method for manufacturing a semiconductor device having field effect transistors according to claim 5, wherein said step of forming said hole in said insulating layer comprises formation of a hole having an approximately rectangular horizontal shape in the insulating layer; said step of forming said first single crystal semiconductor layer portion comprises formation of the single crystal semiconductor layer portion of the first conductivity type having a horizontal shape of approximately rectangular with one side opened along one side wall surface of said hole; said step of forming said second single crystal semiconductor layer portion comprises formation of the single crystal semiconductor layer portion of the second conductivity type having a horizontal shape of approximately rectangular with one side opened along the other side wall surface of said hole opposing to said first single crystal semiconductor layer portion; said steps of forming said first gate electrode and said second gate electrode comprise formation of a conductive layer in a region surrounded by said first single crystal semiconductor layer portion and said second single crystal semiconductor layer portion, insulated therefrom and buried in said hole for forming the gate electrode; said step of forming said first and second impurity regions comprises formation of the impurity regions at opposing end portions of the approximately rectangular shape with one side opened of said first single crystal semiconductor layer portion; and said step of forming said third and fourth impurity regions comprises formation of the impurity regions at opposing end portions of the approximately rectangular shape with one side opened of said second single crystal semiconductor layer portion.
Claim 11
Dependent Claim
115 words
A method for manufacturing a semiconductor device having field effect transistors according to claim 5, wherein said steps of forming said first gate electrode and said second gate electrode comprise formation of an electrode portion buried in said hole for forming the gate electrode and of a contact portion extending from the electrode portion over upper surfaces of said first single crystal semiconductor layer portion and said second single crystal semiconductor layer portion with an insulating layer interposed therebetween; and said steps of forming said first and second impurity regions and said third and fourth impurity regions comprise formation of the impurity regions in selfalignment using said contact portion as a portion of a mask.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1995-03-17 | 1995-09-16 | 1996-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-17 | 1999-09-16 | 2000-03-17 | $3760.00 | Window Closed / Lapsed |
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