US5585648A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High brightness electroluminescent device, emitting in the green to ultraviolet spectrum, and method of making the same
Assignee: Wolfspeed Inc
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Filing: 1995-02-03
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Granted: 1996-12-17
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Expires: 2015-02-03
Abstract
Abstract A green-blue to ultraviolet light-emitting optical device, e.g. a green-blue to ultraviolet emitting laser or a green-blue to ultraviolet emitting diode, comprising a green-blue to ultraviolet light emitting gallium nitride material on a base structure including a silicon carbide substrate, which preferably consists of 2H-SiC, 4H-SiC, or a-axis oriented 6H-SiC. The carrier mobility and the transparency of the silicon carbide substrate are optimized by the selection of orientation and polytype, thus enhancing device performance. The light-emitting diodes may incorporate a structural modification to increase the light output comprising a dielectric Bragg mirror beneath the LED structure, made of alternating layers of AlN, GaN, InN or their alloys. Methods for making such light-emitting diodes are provided, including a technique for defining individual devices by mesa etching which avoids possible damage to the active area during dicing.
Inventors
- 👤 Michael A. Tischler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:19
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/822; H10H20/824; H10H20/825; H10H20/01; H10H20/011; H10H20/013; H10H20/0133; H10H20/01335; H10H20/814; H10H20/8142
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
35 words
A green-blue to ultraviolet light-emitting diode comprising a green-blue to ultraviolet light emitting Ga*N material on a base structure comprising a SiC substrate selected from the group consisting of 2H-SiC, 4H-SiC and a-axis oriented 6H-SiC.
Claim 2
Dependent Claim
35 words
A green-blue to ultraviolet light-emitting diode comprising a green-blue to ultraviolet light emitting Ga*N material on a base structure comprising a SiC substrate selected from the group consisting of 2H-SiC, 4H-SiC and a-axis oriented 6H-SiC.
Claim 3
Dependent Claim
15 words
A light-emitting diode according to claim 1, wherein the SiC substrate is a-axis oriented 6H-SiC.
Claim 4
Dependent Claim
18 words
A light emitting diode according to claim 1, wherein said SiC substrate is an a-axis (1010) oriented 6H-SiC.
Claim 5
Dependent Claim
18 words
A light emitting diode according to claim 1, wherein said SiC substrate is an a-axis (1120) oriented 6H-SiC.
Claim 6
Dependent Claim
21 words
A light-emitting diode according to claim 1, wherein the SiC substrate is selected from the group consisting of 2H-SiC and 4H-SiC.
Claim 7
Dependent Claim
51 words
A light-emitting diode according to claim 1, wherein the Ga*N material comprises an intermediate layer selected from the group consisting of GaN and InGaN, and separate p-type overlying and n-type underlying AlGaN layers adjacent to said intermediate layer, and wherein said n-type underlying AlGaN layer is adjacent to said base structure.
Claim 8
Dependent Claim
13 words
A light-emitting diode according to claim 1, wherein said Ga*N material comprises GaN.
Claim 9
Dependent Claim
13 words
A light-emitting diode according to claim 1, wherein said Ga*N material comprises InGaN.
Claim 10
Dependent Claim
13 words
A light-emitting diode according to claim 1, wherein said Ga*N material comprises AlGaN.
Claim 11
Dependent Claim
13 words
A light-emitting diode according to claim 1, wherein said Ga*N material comprises AlGaInN.
Claim 12
Dependent Claim
25 words
A light-emitting diode according to claim 8, wherein said InGaN has the formula In x Ga 1-x N wherein x ranges from 0.05 to 0.50.
Claim 13
Dependent Claim
25 words
A light-emitting diode according to claim 8, wherein said InGaN has the formula In x Ga 1-x N wherein x is between 0 and 0.15.
Claim 14
Dependent Claim
24 words
A light-emitting diode according to claim 6, wherein said AlGaN layers comprise Al y Ga 1-y N wherein y is between 0 and 0.3.
Claim 15
Dependent Claim
25 words
A light-emitting diode according to claim 6, wherein said AlGaN barrier layer comprises Al y Ga 1-y N wherein y is between 0.05 and 0.15.
Claim 16
Dependent Claim
34 words
A light-emitting diode according to claim 1, wherein the blue-ultraviolet light-emitting Ga*N material emits blue light of a wavelength in the range of from 440 to 480 nm under light-emission excitation conditions effective therefor.
Claim 17
Dependent Claim
32 words
A light-emitting diode according to claim 1, wherein said base structure comprises at least one mesa on a top surface thereof, with said Ga*N material deposited on said at least one mesa.
Claim 18
Dependent Claim
25 words
A light-emitting diode according to claim 16, wherein each said mesa includes a main mesa surface having an equivalent diameter of less than 350 micrometers.
Claim 19
Dependent Claim
25 words
A light-emitting diode according to claim 16, wherein each said mesa includes a main mesa surface having an equivalent diameter of less than 200 micrometers.
Claim 20
Dependent Claim
59 words
A light-emitting diode according to claim 1, wherein the base structure SiC is p-type, and the Ga*N material comprises a p-type Ga*N barrier layer on the base structure, and active Ga*N layer on the p-type Ga*N barrier layer, and n-type Ga*N barrier layer on the Ga*N active layer, and an n-type contact layer on the n-type Ga*N barrier layer.
Claim 21
Dependent Claim
59 words
A light-emitting diode according to claim 1, wherein the base structure SiC is n-type, and the Ga*N material comprises an n-type Ga*N barrier layer on the base structure, an active Ga*N layer on the n-type Ga*N barrier layer, a p-type Ga*N barrier layer on the Ga*N active layer, and a p-type contact layer on the p-type Ga*N barrier layer.
Claim 22
Dependent Claim
17 words
A light-emitting diode according to claim 1, wherein the light-emitting Ga*N material includes a quantum well region.
Claim 23
Dependent Claim
23 words
A light-emitting diode according to claim 1, further comprising a dielectric Bragg mirror layer between the SiC substrate and the light-emitting Ga*N material.
Claim 24
Dependent Claim
17 words
A light-emitting diode according to claim 22, wherein the dielectric Bragg mirror comprises sublayers of Ga*N material.
Claim 25
Dependent Claim
28 words
A light-emitting diode according to claim 1, wherein the base structure comprises a buffer layer on said SiC substrate, between said SiC substrate and said light-emitting Ga*N material.
Claim 26
Dependent Claim
16 words
A light-emitting diode according to claim 24, wherein said buffer layer comprises a strained-layer Ga*N superlattice.
Claim 27
Dependent Claim
85 words
A green-blue to ultraviolet light-emitting diode device, comprising: a base structure including a conductive, n-type SiC substrate selected from the group consisting of 2H-SiC, 4H-SiC and a-axis oriented 6H-SiC; an n-type Ga*N barrier layer on said base structure; a Ga*N active layer on said n-type Ga*N barrier layer; a p-type Ga*N layer on said Ga*N active layer; a heavily doped p-type Ga*N contact layer on said p-type Ga*N layer; an n-type contact on said substrate; and a p-type contact on said p-type Ga*N contact layer.
Claim 28
Dependent Claim
85 words
A green-blue to ultraviolet light-emitting diode device, comprising: a base structure including a conductive, n-type SiC substrate selected from the group consisting of 2H-SiC, 4H-SiC and a-axis oriented 6H-SiC; an n-type Ga*N barrier layer on said base structure; a Ga*N active layer on said n-type Ga*N barrier layer; a p-type Ga*N layer on said Ga*N active layer; a heavily doped p-type Ga*N contact layer on said p-type Ga*N layer; an n-type contact on said substrate; and a p-type contact on said p-type Ga*N contact layer.
Claim 29
Dependent Claim
36 words
A light-emitting diode according to claim 26, wherein the base structure includes a Bragg reflector layer between said SiC substrate and said n-type Ga*N barrier layer, which reflects light of the wavelength emitted by the device.
Claim 30
Dependent Claim
16 words
A light-emitting diode according to claim 27, wherein said wavelength is from 440 to 480 nm.
Claim 31
Dependent Claim
25 words
A light-emitting diode according to claim 26, wherein said Ga*N active layer comprises In x Ga 1-x N wherein x is between 0.05 and 0.50.
Claim 32
Dependent Claim
25 words
A light-emitting diode according to claim 26, wherein said Ga*N active layer comprises In x Ga 1-x N wherein x is between 0.07 and 0.15.
Claim 33
Dependent Claim
25 words
A light-emitting diode according to claim 26, wherein said AlGaN barrier layer comprises Al y Ga 1-y N wherein y is between 0 and 0.3.
Claim 34
Dependent Claim
25 words
A light-emitting diode according to claim 26, wherein said AlGaN barrier layer comprises Al y Ga 1-y N wherein y is between 0.05 and 0.15.
Claim 35
Dependent Claim
40 words
A light-emitting diode according to claim 26, wherein the successive layers on the base structure are of reduced cross-sectional areal extent in relation to the base structure, so that the layers define a multi-layer mesa structure on the base structure.
Claim 36
Dependent Claim
25 words
A light-emitting diode according to claim 33, wherein the mesa structure includes a main mesa surface having an equivalent diameter of less than 50 micrometers.
Claim 37
Dependent Claim
23 words
A light-emitting diode according to claim 26, which has a wavelength of maximum light emission in the range of 400 to 490 nm.
Claim 38
Dependent Claim
23 words
A light-emitting diode according to claim 26, which has a wavelength of maximum light emission in the range of 495 to 545 nm.
Claim 39
Dependent Claim
23 words
A light-emitting diode according to claim 26, which has a wavelength of maximum light emission in the range of 200 to 400 nm.
Claim 40
Dependent Claim
46 words
A green-blue to ultraviolet light-emitting device comprising a green-blue to ultraviolet light emitting Ga*N material on a base structure comprising a SiC substrate selected from the group consisting of 2H-SiC, 4H-SiC and a-axis oriented 6H-SiC, wherein said device is a green-blue to violet light emitting laser.
Claim 41
Dependent Claim
46 words
A green-blue to ultraviolet light-emitting device comprising a green-blue to ultraviolet light emitting Ga*N material on a base structure comprising a SiC substrate selected from the group consisting of 2H-SiC, 4H-SiC and a-axis oriented 6H-SiC, wherein said device is a green-blue to violet light emitting laser.
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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) | 1999-12-17 | 2000-06-17 | 2000-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-12-17 | 2004-06-17 | 2004-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-12-17 | 2008-06-17 | 2008-12-17 | $7700.00 | Window Closed / Lapsed |