Patent US5858855A successfully refreshed from Google Patents.
US5858855A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor substrate, process for production thereof, and semiconductor device
Assignee: Renesas Electronics Corp
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Filing: 1997-06-13
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Granted: 1999-01-12
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Expires: 2017-06-13
Abstract
Abstract The present invention relates to a semiconductor substrate which is a composite substrate obtained by (1) forming, on one side of a first single-crystal silicon substrate of first conductivity and low impurity content, a polycrystalline silicon layer of first conductivity and higher impurity content than the impurity content of the first single-crystal silicon substrate, which layer later becomes a life-time killer of a second-conductivity carrier, (2) bonding, on the polycrystalline silicon layer, a second single-crystal silicon substrate of second conductivity and high impurity content, and (3) subjecting the resulting bonded wafer to a heat treatment, as well as to a process for production of the semiconductor substrate. The present invention relates particularly to a semiconductor substrate useful for formation of a vertical power semiconductor device and a process for production of the semiconductor substrate. The present invention relates also to a semiconductor device obtained using the above semiconductor substrate.
Inventors
- 👤 Kenya Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:20
CPC Classifications
H; H10; H10P; H10P90/00; H10P90/19; H10P90/1904; H10P90/1906; H10P90/1914; H10W; H10W10/00; H10W10/10; H10W10/181
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
101 words
A process for producing a semiconductor substrate comprising: (1) forming, on one side of a first single-crystal silicon substrate of first conductivity and low impurity content, a polycrystalline silicon layer of said first conductivity and higher impurity content than the impurity content of the first single-crystal silicon substrate, which layer later becomes a lifetime killer of a second-conductivity carrier; (2) bonding, on the polycrystalline silicon layer, a second single-crystal silicon substrate of second conductivity and high impurity content; (3) subjecting the resulting bonding wafer to a heat treatment to obtain a composite substrate; and (4) forming a vertical power semiconductor device.
Claim 2
Dependent Claim
101 words
A process for producing a semiconductor substrate comprising: (1) forming, on one side of a first single-crystal silicon substrate of first conductivity and low impurity content, a polycrystalline silicon layer of said first conductivity and higher impurity content than the impurity content of the first single-crystal silicon substrate, which layer later becomes a lifetime killer of a second-conductivity carrier; (2) bonding, on the polycrystalline silicon layer, a second single-crystal silicon substrate of second conductivity and high impurity content; (3) subjecting the resulting bonding wafer to a heat treatment to obtain a composite substrate; and (4) forming a vertical power semiconductor device.
Claim 3
Dependent Claim
132 words
A process for producing a semiconductor substrate comprising: (1) forming, on one side of a first single-crystal silicon substrate of a first conductivity and low impurity content, a polycrystalline silicon layer of said first conductivity and higher impurity content than the impurity content of the first single-crystal silicon substrate, which layer later becomes a lifetime killer of a second-conductivity carrier; (2) forming, on one side of a second single crystal silicon substrate of second conductivity and high impurity content, a polycrystalline silicon layer of said second conductivity and high impurity content; (3) bonding the two substrates so that the respective polycrystalline silicon layers come in contact with each other; (4) subjecting the resulting bonded wafer to a heat treatment to obtain a composite substrate; and (5) forming a vertical power semiconductor device.
Claim 4
Dependent Claim
132 words
A process for producing a semiconductor substrate comprising: (1) forming, on one side of a first single-crystal silicon substrate of a first conductivity and low impurity content, a polycrystalline silicon layer of said first conductivity and higher impurity content than the impurity content of the first single-crystal silicon substrate, which layer later becomes a lifetime killer of a second-conductivity carrier; (2) forming, on one side of a second single crystal silicon substrate of second conductivity and high impurity content, a polycrystalline silicon layer of said second conductivity and high impurity content; (3) bonding the two substrates so that the respective polycrystalline silicon layers come in contact with each other; (4) subjecting the resulting bonded wafer to a heat treatment to obtain a composite substrate; and (5) forming a vertical power semiconductor device.
Claim 5
Dependent Claim
123 words
A process for producing a semiconductor substrate comprising: (1) forming, on one side of a first single-crystal silicon substrate of first conductivity and low impurity content, a polycrystalline silicon layer of said first conductivity and higher impurity content than the impurity content of the first single-crystal silicon substrate, which layer later becomes a lifetime killer of a second-conductivity carrier; (2) forming, on one side of a second single-crystal silicon substrate of second conductivity and high impurity content, an intrinsic polycrystalline silicon layer; (3) bonding the two substrates so that the respective polycrystalline silicon layers come in contact with each other; (4) subjecting the resulting bonding wafer to a heat treatment to obtain a composite substrate; and (5) forming a vertical power semiconductor device.
Claim 6
Dependent Claim
123 words
A process for producing a semiconductor substrate comprising: (1) forming, on one side of a first single-crystal silicon substrate of first conductivity and low impurity content, a polycrystalline silicon layer of said first conductivity and higher impurity content than the impurity content of the first single-crystal silicon substrate, which layer later becomes a lifetime killer of a second-conductivity carrier; (2) forming, on one side of a second single-crystal silicon substrate of second conductivity and high impurity content, an intrinsic polycrystalline silicon layer; (3) bonding the two substrates so that the respective polycrystalline silicon layers come in contact with each other; (4) subjecting the resulting bonding wafer to a heat treatment to obtain a composite substrate; and (5) forming a vertical power semiconductor device.
Claim 7
Dependent Claim
46 words
A process for producing a semiconductor substrate according to claim 1, wherein the grinding and polishing of the other side of the first single-crystal silicon substrate is conducted between the heat treatment of the resulting bonded wafer and the formation of a vertical power semiconductor device.
Claim 8
Dependent Claim
46 words
A process for producing a semiconductor substrate according to claim 2, wherein the grinding and polishing of the other side of the first single-crystal silicon substrate is conducted between the heat treatment of the resulting bonded wafer and the formation of a vertical power semiconductor device.
Claim 9
Dependent Claim
46 words
A process for producing a semiconductor substrate according to claim 3, wherein the grinding and polishing of the other side of the first single-crystal silicon substrate is conducted between the heat treatment of the resulting bonded wafer and the formation of a vertical power semiconductor device.
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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) | 2002-01-11 | 2002-07-13 | 2003-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-01-11 | 2006-07-13 | 2007-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-01-11 | 2010-07-13 | 2011-01-12 | $7700.00 | Window Closed / Lapsed |