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US4865655A
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Gallium arsenide phosphide mixed crystal epitaxial wafer with a graded buffer layer
Assignee: Mitsubishi Chemical Corp
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Filing: 1987-11-18
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Granted: 1989-09-12
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Expires: 2007-11-18
Abstract
Abstract An epitaxial wafer for producing arrays of GaAsP-LEDs comprises, in the GaAs 1-x P x layer with varying X, a layer region(s) with a discontinuous variance of x along the thickness of the GaAs 1-x P x layer. This layer region(s) contribute to a uniformity in the brightness of the light emission of LEDs formed in the epitaxial wafer.
Inventors
- 👤 Hisanori Fujita
- 👤 Masaaki Kanayama
- 👤 Takeshi Okano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:27
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/822; H10H20/824; H10H20/01; H10H20/011; H10H20/013; H10H20/0133; H10H29/00; H10H29/10; H10H29/14; H10P; H10P14/00; H10P14/20; H10P14/24; H10P14/29; H10P14/2901; H10P14/2907; H10P14/2909; H10P14/2911; H10P14/32; H10P14/3202; H10P14/3214; H10P14/3218; H10P14/3221; H10P14/3242; H10P14/3244; H10P14/3248; H10P14/3254; Y; Y10; Y10S; Y10S148/00; Y10S148/041; Y10S148/056; Y10S148/067; Y10S148/072; Y10S148/097; Y10S438/00; Y10S438/936
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
154 words
An epitaxial wafer of gallium arsenide phosphide mixed crystal, having an improved brightness distribution, consisting of a single crystalline substrate, a gallium arsenide phosphide layer formed on the single crystal substrate having a thickness of 5-22 microns and having a mixed crystal ratio varying along a thickness thereof (hereinafter referred to as the graded layer), and a gallium arsenide phosphide layer formed on the graded layer and having a constant mixed crystal ratio along a thickness thereof (hereinafter referred to as the constant layer), wherein said epitaxial wafer comprises, in said graded layer, at least one layer region, in which the mixed crystal ratio of gallium arsenide phosphide discontinuously varies along the thickness thereof, in the range of from 2×10 -2 to 5×10 -2 per micron of thickness and wherein said graded layer was formed by incorporating phosphorus into said graded layer at a rate greater than 1% per micron of said graded layer.
Claim 2
Dependent Claim
154 words
An epitaxial wafer of gallium arsenide phosphide mixed crystal, having an improved brightness distribution, consisting of a single crystalline substrate, a gallium arsenide phosphide layer formed on the single crystal substrate having a thickness of 5-22 microns and having a mixed crystal ratio varying along a thickness thereof (hereinafter referred to as the graded layer), and a gallium arsenide phosphide layer formed on the graded layer and having a constant mixed crystal ratio along a thickness thereof (hereinafter referred to as the constant layer), wherein said epitaxial wafer comprises, in said graded layer, at least one layer region, in which the mixed crystal ratio of gallium arsenide phosphide discontinuously varies along the thickness thereof, in the range of from 2×10 -2 to 5×10 -2 per micron of thickness and wherein said graded layer was formed by incorporating phosphorus into said graded layer at a rate greater than 1% per micron of said graded layer.
Claim 3
Dependent Claim
16 words
An epitaxial wafer according to claim 1, wherein the single crystalline substrate consists of gallium arsenide.
Claim 4
Dependent Claim
16 words
An epitaxial wafer according to claim 1, wherein the single crystalline substrate consists of gallium phosphide.
Claim 5
Dependent Claim
29 words
An epitaxial wafer according to claim 1 or 2, wherein the mixed crystal ratio of the constant layer is one value in the range of from 0.35 to 0.45.
Claim 6
Dependent Claim
13 words
An epitaxial wafer according to claim 4, wherein said one value is 0.4.
Claim 7
Dependent Claim
23 words
An epitaxial wafer according to claim 4, wherein said graded layer has a thickness in the range of from 5 to 200 μm.
Claim 8
Dependent Claim
62 words
An epitaxial wafer according to claim 4 or 6, wherein said graded layer comprises said at least one layer region on an interface between the same and the single crystalline substrate or the constant layer, in which at least one layer region the mixed crystal ratio varies discontinuously with respect to the variance of the mixed crystal ratio of said graded layer.
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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) | 1992-09-11 | 1993-03-13 | 1993-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-11 | 1997-03-13 | 1997-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-11 | 2001-03-13 | 2001-09-12 | $7700.00 | Window Closed / Lapsed |