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US5559349A
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Silicon integrated circuit with passive devices over high resistivity silicon substrate portion, and active devices formed in lower resistivity silicon layer over the substrate
Assignee: Northrop Grumman Corp
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Filing: 1995-03-07
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Granted: 1996-09-24
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Expires: 2015-03-07
Abstract
Abstract A silicon microwave monolothic integrated circuit device and method of fabricating having a high resistivity silicon substrate with a masking layer of low temperature silicon oxide, silicon nitride and polysilicon sublayers on a first area, and an epitaxial layer over the surface of the silicon substrate in a second area. The active devices are formed over the second area and the passive devices are formed over the first area.
Inventors
- 👤 James R. Cricchi
- 👤 Paul A. Potyraj
- 👤 Mike L. Salib
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:33
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/40; H10D84/401
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
145 words
A silicon microwave monolithic integrated circuit device comprising: a high resistivity silicon substrate of a first conductivity type; a masking layer formed over a first area of said substrate comprising a plurality of sub-layers of silicon dioxide atop said first area of said substrate: silicon nitride atop said silicon dioxide sub-layer: and oxidized polysilicon atop said sub-layer of silicon nitride; a well region formed in said substrate and doped with second conductivity type dopant forming a second area of said substrate: a silicon epitaxial layer formed over said second area of said substrate, said silicon epitaxial layer having a second resistivity lower than said high resistivity; a microwave bipolar junction transistor (BJT) formed in said silicon epitaxial layer and a portion of said second area of said substrate; and a passive element formed over said masking layer and said first area of said silicon substrate.
Claim 2
Dependent Claim
145 words
A silicon microwave monolithic integrated circuit device comprising: a high resistivity silicon substrate of a first conductivity type; a masking layer formed over a first area of said substrate comprising a plurality of sub-layers of silicon dioxide atop said first area of said substrate: silicon nitride atop said silicon dioxide sub-layer: and oxidized polysilicon atop said sub-layer of silicon nitride; a well region formed in said substrate and doped with second conductivity type dopant forming a second area of said substrate: a silicon epitaxial layer formed over said second area of said substrate, said silicon epitaxial layer having a second resistivity lower than said high resistivity; a microwave bipolar junction transistor (BJT) formed in said silicon epitaxial layer and a portion of said second area of said substrate; and a passive element formed over said masking layer and said first area of said silicon substrate.
Claim 3
Dependent Claim
20 words
The device of claim 1 wherein the high resistivity of the silicon substrate is at least one thousand ohms centimeter.
Claim 4
Dependent Claim
25 words
The device of claim 1 wherein the low resistivity of the silicon epitaxial layer is in the range of approximately 0.8 to 10 ohms centimeter.
Claim 5
Dependent Claim
17 words
The device of claim 1 wherein the masking layer has a thickness of approximately 3 thousand angstroms.
Claim 6
Dependent Claim
19 words
The device of claim 1 further comprising an oxide layer overlaying both the masking layer and the epitaxial layer.
References Cited (Backward Citations)
US5449953A
Cited
US5268315A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-09-24 | 2000-03-25 | 2000-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-09-24 | 2004-03-25 | 2004-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-09-24 | 2008-03-25 | 2008-09-24 | $7700.00 | Window Closed / Lapsed |