US4439910A
Expired / Lapsed
US
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Process for fabrication of monolithic transistor coupled electroluminescent diode
Assignee: The AT&T MVPD Group LLC
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Filing: 1982-05-20
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Granted: 1984-04-03
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Expires: 2002-05-20
Abstract
Abstract Modulated signal levels in the range of 1 μV, as is typical for radar returns, can be used to achieve a useful modulated optical signal that can be launched into a fiber optic waveguide for transmission to a remote location for signal processing. The device of the invention achieves such a conversion by suitably integrating a high gain bipolar transistor with an electroluminescent diode, such as a light emitting diode or diode laser, into a compact monolithic structure. In one structural configuration, the bipolar transistor comprises an emitter comprising a layer of doped n-(Al,Ga)As supported on a base comprising a layer of doped p-GaAs, in turn supported on a collector comprising a layer of undoped n-GaAs or n-(Al,Ga)As. The electroluminescent diode in this embodiment comprises a light-emitting diode formed by a p-n junction between the undoped n-GaAs or n-(Al,Ga)As layer and a supporting doped p-GaAs layer, in turn supported on a doped p + -GaAs substrate. Collector contact is made to the backside of the substrate. An electrical signal at the base is amplified by transistor action, resulting in a high gain optical output by the LED, which may be launched into an optical fiber in either a Burrus or edge-emitting configuration. Direct optical amplification of optical radiation may be made by omitting electrical contact to the base and introducing the optical radiation into the emitter.
Inventors
- 👤 Prahalad K. Vasudev
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:33
CPC Classifications
H; H10; H10H; H10H29/00; H10H29/10; G; G02; G02B; G02B6/00; G02B6/24; G02B6/42; G02B6/4201; G02B6/4202
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
178 words
A process for fabricating an amplifier for amplifying optical radiation which comprises: (a) providing a highly doped substrate of a compound semiconductor material having a first conductivity; (b) forming on at least a portion of said substrate a first epitaxial layer of a compound semiconductor material having the same conductivity as said substrate; (c) forming on at least a portion of said first layer a second epitaxial layer of a compound semiconductor material having a conductivity opposite to that of said first layer and being essentially undoped; (d) forming on at least a portion of said second layer a third epitaxial layer of a compound semiconductor material having a conductivity the same as said first layer, said third layer having a thickness sufficient to provide the amplifier with a high emitter injection efficiency; (e) forming on a portion of said third layer a fourth epitaxial layer of a mixed compound semiconductor having a conductivity the same as said second layer; (f) forming an ohmic contact to said fourth layer; and (g) forming an ohmic contact to said substrate.
Claim 2
Dependent Claim
178 words
A process for fabricating an amplifier for amplifying optical radiation which comprises: (a) providing a highly doped substrate of a compound semiconductor material having a first conductivity; (b) forming on at least a portion of said substrate a first epitaxial layer of a compound semiconductor material having the same conductivity as said substrate; (c) forming on at least a portion of said first layer a second epitaxial layer of a compound semiconductor material having a conductivity opposite to that of said first layer and being essentially undoped; (d) forming on at least a portion of said second layer a third epitaxial layer of a compound semiconductor material having a conductivity the same as said first layer, said third layer having a thickness sufficient to provide the amplifier with a high emitter injection efficiency; (e) forming on a portion of said third layer a fourth epitaxial layer of a mixed compound semiconductor having a conductivity the same as said second layer; (f) forming an ohmic contact to said fourth layer; and (g) forming an ohmic contact to said substrate.
Claim 3
Dependent Claim
15 words
The process of claim 1 further comprising forming an ohmic contact to said third layer.
Claim 4
Dependent Claim
62 words
The process of claim 1 further comprising forming an epitaxial layer of a mixed compound semiconductor material between said substrate and said first layer, having the same conductivity as said substrate and said first layer, and forming an epitaxial layer of a mixed compound semiconductor material between said second layer and said third layer, having the same conductivity as said second layer.
Claim 5
Dependent Claim
26 words
The process of claim 1 in which said compound semiconductor material and said mixed compound semiconductor material are selected from the class of III-V semiconductor materials.
Claim 6
Dependent Claim
31 words
The process of claim 4 in which the difference between the bandgap of said mixed compound semiconductor material and that of said compound semiconductor material is at least about 0.5 eV.
Claim 7
Dependent Claim
21 words
The process of claim 4 in which said compound semiconductor material comprises GaAs and said mixed compound semiconductor material comprises (Al,Ga)As.
Claim 8
Dependent Claim
197 words
The process of claim 6 which comprises: (a) providing a highly doped substrate of p-type GaAs, doped to greater than about 10 18 cm -3 ; (b) forming on at least a portion of said substrate a first epitaxial layer of p-type GaAs, said layer of p-type GaAs having a carrier concentration of about 1×10 17 cm -3 ; (c) forming on at least a portion of said first layer a second epitaxial layer of a material selected from the group consisting of n-type GaAs and n-type Al x Ga 1-x As, where x ranges from about 0.6 to 0.9; (d) forming on at least a portion of said second layer a third epitaxial layer of p-type GaAs having a carrier concentration of about 1×10 18 cm -3 and a thickness ranging from about 0.2 to 0.5 μm; (e) forming on a portion of said third layer a fourth epitaxial layer of n-type Al y Ga 1-y As having a carrier concentration of about 1×10 17 cm -3 and a value of y ranging from about 0.3 to 0.9; (f) forming an ohmic contact to said fourth layer; and (g) forming an ohmic contact to said substrate.
Claim 9
Dependent Claim
15 words
The process of claim 7 further comprising forming an ohmic contact to said third layer.
Claim 10
Dependent Claim
76 words
The process of claim 7 further comprising forming between said substrate and said first layer an epitaxial layer of p-type Al x Ga 1-x As, where x is about 0.6, having a carrier concentration of about 1×10 17 cm -3 and forming between said second layer and said third layer an epitaxial layer of n-type Al x Ga 1-x As, where x is about 0.6, having a carrier concentration of about 1×10 17 cm -3 .
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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) | 1987-04-03 | 1987-10-03 | 1988-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-03 | 1991-10-03 | 1992-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-03 | 1995-10-03 | 1996-04-03 | $7700.00 | Window Closed / Lapsed |