Patent US4980747A successfully refreshed from Google Patents.
US4980747A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Deep trench isolation with surface contact to substrate
Assignee: Texas Instruments Inc
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Filing: 1988-10-18
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Granted: 1990-12-25
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Expires: 2008-10-18
Abstract
Abstract A trench structure and fabrication technique is disclosed for isolating adjacent circuits in an integrated circuit. A trench (26) is coated with an oxidation barrier (18) of silicon to protect underlying semiconductor regions (34, 36) from crystal faults and dislocations caused by high temperature oxidation. The trench (26) includes a bottom (50) formed of the substrate (10). The trench (26) is filled with a conductive material which is in electrical contact with the substrate (10). A top surface contact electrode (74) is formed over the trench, in contact therewith, thereby also contacting the underlying substrate (10). For very narrow trenches, semiconductor areas (68, 70) are formed adjacent the top of the trench to thereby provide additional contact surface for the electrode (74).
Inventors
- 👤 Louis N. Hutter
- 👤 James D. Goon
- 👤 Shiu-Hang Yan
- 👤 Gopal K. Rao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:02
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/041; H10W10/40; H10W20/00; H10W20/01; H10W20/021
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
205 words
A semiconductor structure with insulated areas, comprising: (a) a semiconductor substrate of a first conductivity type; (b) an epitaxial layer of semiconductor material formed on said substrate and comprising a material of a second conductivity type; (c) a trench in said epitaxial layer and extending therethrough to said substrate for defining two semiconductor regions of said semiconductor material each on an opposite side of said trench; (d) a conductive semiconductor material of said first conductivity type filling said trench and in electrical contact at the bottom of said trench with said substrate; (e) an insulating layer formed on the sidewalls of said trench between said conductive semiconductor material filling said trench and said epitaxial layer of semiconductor material for providing electrical isolation between said two semiconductor regions in said epitaxial layer and said conductive semiconductor material filling said trench; (f) a semiconductor area of said first conductivity type formed in a face of said layer of semiconductor material of said second conductivity type and adjacent said conductive semiconductor material filling said trench; (g) a topside contact having a width greater than the width of said trench and being formed in electrical contact with the top end of said trench filling material and said semiconductor area.
Claim 2
Dependent Claim
205 words
A semiconductor structure with insulated areas, comprising: (a) a semiconductor substrate of a first conductivity type; (b) an epitaxial layer of semiconductor material formed on said substrate and comprising a material of a second conductivity type; (c) a trench in said epitaxial layer and extending therethrough to said substrate for defining two semiconductor regions of said semiconductor material each on an opposite side of said trench; (d) a conductive semiconductor material of said first conductivity type filling said trench and in electrical contact at the bottom of said trench with said substrate; (e) an insulating layer formed on the sidewalls of said trench between said conductive semiconductor material filling said trench and said epitaxial layer of semiconductor material for providing electrical isolation between said two semiconductor regions in said epitaxial layer and said conductive semiconductor material filling said trench; (f) a semiconductor area of said first conductivity type formed in a face of said layer of semiconductor material of said second conductivity type and adjacent said conductive semiconductor material filling said trench; (g) a topside contact having a width greater than the width of said trench and being formed in electrical contact with the top end of said trench filling material and said semiconductor area.
Claim 3
Dependent Claim
16 words
The semiconductor structure of claim 1 wherein said topside contact is connected to a circuit ground.
Claim 4
Dependent Claim
20 words
The semiconductor structure of claim 1 wherein said trench is a narrow trench having a width of about 2-3 microns.
Claim 5
Dependent Claim
237 words
A trench isolated semiconductor structure, comprising: (a) a substrate of a given conductivity type having an epitaxial layer of an opposite conductivity type disposed thereon; (b) an isolation trench formed in said epitaxial layer and extending therethrough to said substrate for providing lateral electrical isolation between first and second regions of said epitaxial layer on opposite sides of said trench; (c) a conductive semiconductor material of the same conductivity type as said substrate filling said trench and in electrical contact at the bottom of said trench with said substrate; (d) an insulating layer formed on each sidewall of said trench between said conductive material filling said trench and said epitaxial layer for providing electrical isolation between said conductive material filling said trench and said first and second regions of said epitaxial layer, said insulating layer comprising an oxide layer disposed on said sidewalls and a nitride layer disposed on said oxide layer; (e) a topside contact formed over said trench and in electrical contact with said conductive material filling said trench, said contact having a width greater than said trench, a portion of said contact overlying said epitaxial layer; and (f) a semiconductor region of the same conductivity type as said substrate and disposed in a face of said epitaxial layer adjacent to each upper corner of said trench for providing electrical isolation between said epitaxial layer and said portion of said contact overlying said epitaxial layer.
Claim 6
Dependent Claim
237 words
A trench isolated semiconductor structure, comprising: (a) a substrate of a given conductivity type having an epitaxial layer of an opposite conductivity type disposed thereon; (b) an isolation trench formed in said epitaxial layer and extending therethrough to said substrate for providing lateral electrical isolation between first and second regions of said epitaxial layer on opposite sides of said trench; (c) a conductive semiconductor material of the same conductivity type as said substrate filling said trench and in electrical contact at the bottom of said trench with said substrate; (d) an insulating layer formed on each sidewall of said trench between said conductive material filling said trench and said epitaxial layer for providing electrical isolation between said conductive material filling said trench and said first and second regions of said epitaxial layer, said insulating layer comprising an oxide layer disposed on said sidewalls and a nitride layer disposed on said oxide layer; (e) a topside contact formed over said trench and in electrical contact with said conductive material filling said trench, said contact having a width greater than said trench, a portion of said contact overlying said epitaxial layer; and (f) a semiconductor region of the same conductivity type as said substrate and disposed in a face of said epitaxial layer adjacent to each upper corner of said trench for providing electrical isolation between said epitaxial layer and said portion of said contact overlying said epitaxial layer.
Claim 7
Dependent Claim
24 words
A trench isolated semiconductor structure as recited in claim 4 wherein said trench is a narrow trench having a width of about 2≦3 microns.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-24 | 1994-06-25 | 1994-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-24 | 1998-06-25 | 1998-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-24 | 2002-06-25 | 2002-12-25 | $7700.00 | Window Closed / Lapsed |