Patent US3936855A successfully refreshed from Google Patents.
US3936855A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light-emitting diode fabrication process
Assignee: International Telephone and Telegraph Corp
•
Filing: 1974-08-08
•
Granted: 1976-02-03
•
Expires: 1994-08-08
Abstract
Abstract A method and structure are provided for the simplified batch fabrication of Gallium Arsenide-Aluminum Gallium Arsenide lightemitting diodes. A high aluminum content AlGaAs layer is formed on the GaAs substrate layer to provide an etch resistant mask, and an etchant is employed which preferentially etches the GaAs. This permits simultaneous etching of the substrate to form a plurality of like devices on a common semiconductor wafer in a repeatable low-cost batch process.
Inventors
- 👤 James Emanuel Goell
- 👤 Yet-Zen Liu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:15
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/819; H10P; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/646
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
121 words
A gallium arsenide-aluminum gallium arsenide light-emitting diode comprising, a GaAs substrate layer of a first conductivity type, said GaAs layer being capable of being etched by a given etchant, a first AlGaAs layer of said first conductivity type on said substrate layer, said first AlGaAs layer having a sufficiently high concentration of aluminum so that said first AlGaAs layer is resistant to etching by said given etchant, a first AlGaAs layer of a second conductivity type over said first AlGaAs layer of said first type, a second AlGaAs layer of said second conductivity type on said first AlGaAs layer of said second type, and a GaAs layer of said second conductivity type on said second AlGaAs layer of said second type.
Claim 2
Dependent Claim
121 words
A gallium arsenide-aluminum gallium arsenide light-emitting diode comprising, a GaAs substrate layer of a first conductivity type, said GaAs layer being capable of being etched by a given etchant, a first AlGaAs layer of said first conductivity type on said substrate layer, said first AlGaAs layer having a sufficiently high concentration of aluminum so that said first AlGaAs layer is resistant to etching by said given etchant, a first AlGaAs layer of a second conductivity type over said first AlGaAs layer of said first type, a second AlGaAs layer of said second conductivity type on said first AlGaAs layer of said second type, and a GaAs layer of said second conductivity type on said second AlGaAs layer of said second type.
Claim 3
Dependent Claim
39 words
The device of claim 1 wherein said first AlGaAs layer of said first type includes an aluminum concentration according to the formula Al x Ga 1 -x As where x is in the range of from 0.5 to 1.0.
Claim 4
Dependent Claim
17 words
The device of claim 2 wherein said etchant includes a mixture of hydrogen peroxide and ammonium hydroxide.
Claim 5
Dependent Claim
88 words
The device of claim 2 including a junction of opposite conductivity types between said first AlGaAs layer of said second type and said first AlGaAs layer of said first type, a silicon oxide layer having a contact hole on said GaAs layer of said second type, a first metallic contact layer on said silicon oxide layer, a second metallic contact layer on the opposite side of said GaAs substrate layer, and a light emittng well hole in said second metallic contact layer and in said GaAs substrate layer.
Claim 6
Dependent Claim
60 words
The device of claim 2 wherein said first AlGaAs layer of said first type includes a second AlGaAs layer of said first type of a lower aluminum concentration on said first AlGaAs layer of high aluminum, said first AlGaAs layer of said second type forming a junction of opposite conductivity types with said second AlGaAs layer of said first type.
Claim 7
Independent Claim
210 words
A method of making gallium arsenide-aluminum gallium arsenide light-emitting diodes comprising the steps of: forming a first GaAlAs layer of a fist conductivity type on a substrate layer of GaAs of a first conductivity type, said GaAs layer being capable of being etched by a given etchant, said first AlGaAs layer having a sufficiently high concentration of aluminum so that said first AlGaAs layer is resistant to etching by said given etchant, forming a first AlGaAs layer of a second conductivity type over said first AlGaAs layer of said first type, forming a second AlGaAs layer of said second conductivity type on said first AlGaAs layer of said second type, forming a GaAs layer of a second conductivity type on said second AlGaAs layer of said second type, forming a silicon oxide layer on said GaAs layer of said second type, forming a contact hole in said silicon oxide layer, forming metallic contact layers respectively on said silicon oxide layer and on the opposite surface of said substrate layer of GaAs, masking and etching a hole in said metal layer on said opposite surface, and etching a hole in said substrate layer with an etchant which preferentially etches GaAs but substantially does not etch said high aluminum concentration AlGaAs layer.
Claim 8
Independent Claim
210 words
A method of making gallium arsenide-aluminum gallium arsenide light-emitting diodes comprising the steps of: forming a first GaAlAs layer of a fist conductivity type on a substrate layer of GaAs of a first conductivity type, said GaAs layer being capable of being etched by a given etchant, said first AlGaAs layer having a sufficiently high concentration of aluminum so that said first AlGaAs layer is resistant to etching by said given etchant, forming a first AlGaAs layer of a second conductivity type over said first AlGaAs layer of said first type, forming a second AlGaAs layer of said second conductivity type on said first AlGaAs layer of said second type, forming a GaAs layer of a second conductivity type on said second AlGaAs layer of said second type, forming a silicon oxide layer on said GaAs layer of said second type, forming a contact hole in said silicon oxide layer, forming metallic contact layers respectively on said silicon oxide layer and on the opposite surface of said substrate layer of GaAs, masking and etching a hole in said metal layer on said opposite surface, and etching a hole in said substrate layer with an etchant which preferentially etches GaAs but substantially does not etch said high aluminum concentration AlGaAs layer.
Claim 9
Dependent Claim
39 words
The method of claim 6 wherein said first AlGaAs layer of said first type includes an aluminum concentration according to the formula Al x Ga 1 -x As where x is in the range of from 0.5 to 1.0.
Claim 10
Dependent Claim
18 words
The method of claim 7 wherein said preferential etchant includes a mixture of hydrogen peroxide and ammonium hydroxide.
Claim 11
Dependent Claim
58 words
The method of claim 7 wherein a second AlGaAs layer of said first type of a lower aluminum concentration is formed on said first AlGaAs layer of said first type, said first AlGaAs layer of said second type being formed on said second AlGaAs layer of said first type and forming a junction of opposite conductivity types therewith.
Claim 12
Dependent Claim
30 words
The method of claim 7 wherein said first AlGaAs layer of said first type and said first AlGaAs layer of said second type form a junction of opposite conductivity types.
Claim 13
Dependent Claim
41 words
The method of claim 7 wherein a plurality of like holes are etched in said metal layer on said opposite surface and in said substrate layer in simultaneous etching steps to form a plurality of said diodes on a common wafer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-02-02 | 1979-08-04 | 1980-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-02 | 1983-08-04 | 1984-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-02 | 1987-08-04 | 1988-02-03 | $7700.00 | Window Closed / Lapsed |