US4591889A
Expired / Lapsed
US
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Superlattice geometry and devices
Assignee: Nokia Bell Labs
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Filing: 1984-09-14
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Granted: 1986-05-27
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Expires: 2004-09-14
Abstract
Abstract Semiconductor devices having submonolayer superlattices are described. These devices may have periodic compositional variations in a direction parallel to the substrate surface as well as in the perpendicular direction. Such superlattices are useful in numerous types of devices including lasers, transistors, etc.
Inventors
- 👤 Arthur C. Gossard
- 👤 Pierre M. Petroff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:54
CPC Classifications
B; B82; B82Y; B82Y10/00; H; H10; H10D; H10D62/00; H10D62/80; H10D62/81; H10D62/815; H10D62/8161; H10D62/8181; H10D30/00; H10D30/40; H10D30/43
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
73 words
A device comprising a substrate having a surface, said surface being misoriented with respect to a major crystallographic plane, said surface having a plurality of steps, said steps having a height and a width and being arranged periodically, a first plurality of regions on a portion of said steps having a first composition, a second plurality of regions having a second composition, said first and said second pluralities being interleaved with each other.
Claim 2
Independent Claim
73 words
A device comprising a substrate having a surface, said surface being misoriented with respect to a major crystallographic plane, said surface having a plurality of steps, said steps having a height and a width and being arranged periodically, a first plurality of regions on a portion of said steps having a first composition, a second plurality of regions having a second composition, said first and said second pluralities being interleaved with each other.
Claim 3
Dependent Claim
19 words
A device as recited in claim 1 in which said first and second pluralities form a first horizontal superlattice.
Claim 4
Dependent Claim
54 words
A device as recited in claim 2 in which the first and second compositions of said first and second pluralities comprise (A) n and (B) m , respectively, and n and m are the fractions of said width covered by said first and second compositions, respectively, n and m both being greater than 0.0.
Claim 5
Dependent Claim
14 words
A device as recited in claim 3 in which A and B comprise semiconductors.
Claim 6
Dependent Claim
22 words
A device as recited in claim 4 in which said semiconductors are selected from the group consisting of Group III-V compound semiconductors.
Claim 7
Dependent Claim
15 words
A device as recited in claim 5 in which (n+m) is equal to an integer.
Claim 8
Dependent Claim
49 words
A device as recited in claim 3 further comprising a third plurality of regions having a third composition and a fourth plurality of regions having a fourth composition, said third and fourth pluralities being interleaved with each other on said first horizontal superlattice and forming a second horizontal superlattice.
Claim 9
Dependent Claim
40 words
A device as recited in claim 7 in which said third and fourth compositions comprise (C) o and (D) p , respectively, and o and p are the fractions of said width covered by said third and fourth compositions, respectively.
Claim 10
Dependent Claim
14 words
A device as recited in claim 8 in which C and D comprise semiconductors.
Claim 11
Dependent Claim
22 words
A device as recited in claim 9 in which said semiconductors are selected from the group consisting of Group III-V compound semiconductors.
Claim 12
Dependent Claim
18 words
A device as recited in claim 8 further comprising a third horizontal superlattice on said second horizontal superlattice.
Claim 13
Dependent Claim
17 words
A device as recited in claim 4 further comprising a first semiconductor layer on said horizontal superlattice.
Claim 14
Dependent Claim
25 words
A device as recited in claim 12 in which said first plurality of regions has a bandgap less than the bandgaps of adjacent semiconductor regions.
Claim 15
Dependent Claim
20 words
A device as recited in claim 12 in which said first plurality is less heavily doped than said second plurality.
Claim 16
Dependent Claim
17 words
A device as recited in claim 12 further comprising first and second electrical contacts to said device.
Claim 17
Dependent Claim
26 words
A device as recited in claim 15 further comprising a third electrical contact to said device, said third contact being between said first and second contacts.
Claim 18
Dependent Claim
19 words
A device as recited in claim 15 in which said surface and said semiconductor layer have opposite conductivity types.
Claim 19
Dependent Claim
57 words
A device as recited in claim 16 further comprising a second horizontal superlattice comprising third and fourth pluralities of regions interleaved with each other and a second semiconductor layer, said second horizontal superlattice and semiconductor layers being between said first horizontal superlattice and said semiconductor layer and said second horizontal superlattice being nearest said first semiconductor layer.
Claim 20
Dependent Claim
27 words
A device as recited in claim 18 in which said first and third pluralities have a conductivity type opposite to that of said second and fourth pluralities.
Claim 21
Dependent Claim
46 words
A device as recited in claim 2 comprising a semiconductor layer and an active layer between said semiconductor layer and said horizontal superlattice, said surface and said semiconductor layer having opposite conductivity types, said active layer having a bandgap less than the bandgaps of adjacent regions.
Claim 22
Dependent Claim
17 words
A device as recited in claim 20 further comprising first and second electrical contacts to said device.
Claim 23
Dependent Claim
18 words
A device as recited in claim 21 in which said first and second pluralities have different refractive indices.
References Cited (Backward Citations)
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) | 1989-05-26 | 1989-11-25 | 1990-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-26 | 1993-11-25 | 1994-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-26 | 1997-11-25 | 1998-05-27 | $7700.00 | Window Closed / Lapsed |