US4814288A
Expired / Lapsed
US
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Method of fabricating semiconductor devices which include vertical elements and control elements
Assignee: Hitachi Ltd
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Filing: 1987-07-10
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Granted: 1989-03-21
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Expires: 2007-07-10
Abstract
Abstract A method of fabricating semiconductor devices which include vertical elements and control elements. A well is formed by etching in a semiconductor substrate of a first conductivity type, and a first epitaxial layer having a second conductivity type opposite to the first conductivity type is epitaxially grown, followed by etching and/or grinding and/or polishing to fill said well. Further, a second epitaxial layer of the first conductivity type is epitaxially grown on the substrate and on the first epitaxial layer, and an impurity-doped layer of the second conductivity type for isolation is formed in the second epitaxial layer to penetrate therethrough. A first element is formed in the second epitaxial layer in a portion that corresponds to the well, and a second element having a vertical structure and having a current capability higher than that of the first element is formed except a portion of the second epitaxial layer that corresponds to the well.
Inventors
- 👤 Masatoshi Kimura
- 👤 Takeaki Okabe
- 👤 Isao Yoshida
- 👤 Kouzou Sakamoto
- 👤 Kazuo Hoya
- 👤 Kouichiro Satonaka
- 👤 Toyomasa Koda
- 👤 Shigeo Ohtaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:09
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/0107; H10D84/0109; H10D84/02; H10D84/03; H10D84/038; H10D84/40; H10D84/401
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
167 words
A method of fabricating semiconductor devices comprising: a step for forming a well by selectively etching a semiconductor substrate of a first conductivity type a step for epitaxially growing a first epitaxial layer having a second conductivity type opposite to said first conductivity type so as to fill said well; a step for epitaxially growing a second epitaxial layer of the first conductivity type on said substrate and on said first epitaxial layer; a step for forming an impurity-doped layer of the second conductivity type for isolation in said second epitaxial layer ro penetrate through said second epitaxial layer to said first epitaxial layer; a step for forming a first transistor in a portion of said second epitaxial layer corresponding to said well; and a step for forming a second transistor having a vertical structure, and a current capability higher than that of said first transistor in a portion of said second eptitaxial layer other than the portion of the second epitaxial layer corresponding to said well.
Claim 2
Independent Claim
167 words
A method of fabricating semiconductor devices comprising: a step for forming a well by selectively etching a semiconductor substrate of a first conductivity type a step for epitaxially growing a first epitaxial layer having a second conductivity type opposite to said first conductivity type so as to fill said well; a step for epitaxially growing a second epitaxial layer of the first conductivity type on said substrate and on said first epitaxial layer; a step for forming an impurity-doped layer of the second conductivity type for isolation in said second epitaxial layer ro penetrate through said second epitaxial layer to said first epitaxial layer; a step for forming a first transistor in a portion of said second epitaxial layer corresponding to said well; and a step for forming a second transistor having a vertical structure, and a current capability higher than that of said first transistor in a portion of said second eptitaxial layer other than the portion of the second epitaxial layer corresponding to said well.
Claim 3
Dependent Claim
42 words
A method of fabricating semiconductor devices according to claim 1, wherein after said epitaxial layer is formed, a heavily doped buried layer of the first conductivity type is formed in said first epitaxial layer, and then said second epitaxial layer is formed.
Claim 4
Dependent Claim
28 words
A method of fabricating semiconductor devices according to claim 1, wherein said first transistor consists of a bipolar transistor and said second transistor consists of a MOS transistor.
Claim 5
Dependent Claim
32 words
A method of fabricating semiconductor devices according to claim 1, wherein said first transistor consists of a bipolar transistor and a MOS transistor, and said second transistor consists of a MOS transistor.
Claim 6
Dependent Claim
31 words
A method of fabricating semiconductor devices according to claim 1, wherein said first transistor consists of a bipolar transistor and a MOS transistor, and said second transistor consists a bipolar transistor.
Claim 7
Dependent Claim
45 words
A method of fabricating semiconductor devices according to claim 1, including the further step of forming a diffusion layer of the first conductivity type, extending through the second epitaxial layer, said diffusion layer being positioned between the second transistor and the impurity-doped layer for isolation.
Claim 8
Dependent Claim
25 words
A method of fabricating semiconductor devices according to claim 1, wherein said first transistor includes an n-channel MOSFET and a p-channel forming a CMOS structure.
Claim 9
Dependent Claim
19 words
A method of fabricating semiconductor devices according to claim 1, wherein said second transistor is a power npn transistor.
Claim 10
Dependent Claim
138 words
A method of fabricating semiconductor devices according to claim 1, wherein said step for epitaxially growing the first epitaxial layer having the second conductivity type opposite to the first conductivity type further comprises: a step for forming a first insulating film on said substrate; a step for patterning said first insulating film by photoetching into a desired shape; a step for forming a well in said semiconductor substrate by etching with said first insulating film as a mask; a step for removing said first insulating film; a step for epitaxialky growing said first epitaxial layer on said semiconductor substrate; a step for forming an etching-resistant film in a portion of said first epitaxial layer that corresponds to said well; and a step for removing a portion of said first epitaxial layer so as to provide a filled well.
Claim 11
Dependent Claim
28 words
A method of fabricating semiconductor devices according to claim 9, wherein the step fro removing a portion of the first epitaxial layer includes etching the first epitaxial layer.
Claim 12
Dependent Claim
30 words
A method of fabricating semiconductor devices according to claim 9, wherein the step for removing a portion of the first epitaxial layer includes grinding and polishing the first epitaxial layer.
Claim 13
Dependent Claim
30 words
A method of fabricating semiconductor devices according to claim 9, wherein the step for removing a portion of the first epitaxial layer includes etching and polishing the first epitaxial layer.
Claim 14
Dependent Claim
43 words
A method of fabricating semiconducttor devices according to claim 9, wherein after said first epitaxial layer is formed, a heavily doped buried layer of the first conductivity type is provided in said first epitaxial layer, and then said second epitaxial layer is formed.
Claim 15
Dependent Claim
28 words
A method of fabricating semiconductor devices according to claim 13, wherein said first transistor consists of a bipolar transistor and said second element consists of a MOS transistor.
Claim 16
Dependent Claim
33 words
A method of fabricating a semiconductor device according to claim 13, wherein said first element consists of a bipolar transistor and a MOS transistor, and said second element consists of a MOS transistor.
Claim 17
Dependent Claim
65 words
A method of fabricating semiconductor devices according to claim 1, wherein said step for epitaxially growing a first epitaxial layer includes sub-steps of forming the first epitaxial layer to fill the well and to extend on the substrate, and of removing a portion of the formed first epitaxial layer so as to leave the well filled with a remaining portion of the first epitaxial layer.
Claim 18
Dependent Claim
33 words
A method of fabricating semiconductor devices according to claim 16, wherein the sub-step of removing a portion of the first epitaxial layer provides a planor surface of the filled well and substrate surface.
Claim 19
Dependent Claim
19 words
A method of fabricating semiconductor devices according to claim 16, wherein the sub-step of removing exposes the substrate surface.
Claim 20
Dependent Claim
21 words
A method of fabricating semiconductor devices according to claim 11, wherein the sub-step of removing includes etching the first epitaxial layer.
Claim 21
Dependent Claim
23 words
A method of fabricaring semiconductor devices according to claim 16, wherein the sub-step of removing includes grinding and polishing the first epitaxial layer.
Claim 22
Dependent Claim
23 words
A method of fabricating semiconductor devices according to claim 16, wherein the sub-step of removing includes etching and polishing the first epitaxial layer.
Claim 23
Independent Claim
236 words
A method of fabricating semiconductor devices comprising: a step for epitaxially growing a first epitaxial layer having a second conductivity type opposite to a first conductivity type on a semiconductor substrate of said first conductivity type; a step for forming a first insulating film on said first epitaxial layer; a step for patterning said first insulating film by photoetching into a desired shape; a step for forming a well in said first epitaxial layer by etching with said first insulating film as a mask; a step for removing said first insulating film; a step for epitaxially growing a second epitaxial layer of the first conductivity type on said first epitaxial layer and in said well; a step for removing a portion of said second epitaxial layer so as to provide a filled well; a step for forming an impurity-doped layer of the second conductivity type for isolation in said second epitaxial layer so as to penetrate through the second epitaxial layer to the first epitaxial layer; a step for forming at least one first transistor having a vertical structure in a portion of said second epitaxial layer that corresponds to said well; and a step for forming at least one second transistor in said second epitaxial layer in a portion other than the portion that corresponds to said well, a first transistor having a current capability higher than that of the at least one second transistor.
Claim 24
Independent Claim
236 words
A method of fabricating semiconductor devices comprising: a step for epitaxially growing a first epitaxial layer having a second conductivity type opposite to a first conductivity type on a semiconductor substrate of said first conductivity type; a step for forming a first insulating film on said first epitaxial layer; a step for patterning said first insulating film by photoetching into a desired shape; a step for forming a well in said first epitaxial layer by etching with said first insulating film as a mask; a step for removing said first insulating film; a step for epitaxially growing a second epitaxial layer of the first conductivity type on said first epitaxial layer and in said well; a step for removing a portion of said second epitaxial layer so as to provide a filled well; a step for forming an impurity-doped layer of the second conductivity type for isolation in said second epitaxial layer so as to penetrate through the second epitaxial layer to the first epitaxial layer; a step for forming at least one first transistor having a vertical structure in a portion of said second epitaxial layer that corresponds to said well; and a step for forming at least one second transistor in said second epitaxial layer in a portion other than the portion that corresponds to said well, a first transistor having a current capability higher than that of the at least one second transistor.
Claim 25
Dependent Claim
33 words
A method of fabricating semiconductor devices according to claim 22, wherein the step of removing a portion of the second epitaxial layer leaves a remaining portion on the substrate and in the well.
Claim 26
Dependent Claim
67 words
A method of fabricating semiconductor devices according to claim 22, wherein the step for removing is performed by etching, and the method includes the further steps of forming an etching-resistant film on a portion of the second epitaxial layer that corresponds to said well prior to the etching, and removing the etching-resistant film after the etching, the etching being performed using the etching-resistant film as a mask.
Claim 27
Dependent Claim
21 words
A method of fabricating semiconductor devices according to claim 22, wherein the step for removing is performed by grinding and polishing.
Claim 28
Dependent Claim
21 words
A method of fabricating semiconductor devices according to claim 22, wherein the step for removing is performed by grinding and polishing.
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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) | 1992-03-20 | 1992-09-19 | 1993-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-20 | 1996-09-19 | 1997-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-20 | 2000-09-19 | 2001-03-21 | $7700.00 | Window Closed / Lapsed |