CA1058732A - Light emitting diodes with increased light emission efficiency - Google Patents
Light emitting diodes with increased light emission efficiencyInfo
- Publication number
- CA1058732A CA1058732A CA254,639A CA254639A CA1058732A CA 1058732 A CA1058732 A CA 1058732A CA 254639 A CA254639 A CA 254639A CA 1058732 A CA1058732 A CA 1058732A
- Authority
- CA
- Canada
- Prior art keywords
- layer
- aperture
- confining
- light emitting
- substrate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/025—Physical imperfections, e.g. particular concentration or distribution of impurities
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4202—Packages, e.g. shape, construction, internal or external details for coupling an active element with fibres without intermediate optical elements, e.g. fibres with plane ends, fibres with shaped ends, bundles
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/20—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/36—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
- H01L33/40—Materials therefor
- H01L33/405—Reflective materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
- H01L33/0093—Wafer bonding; Removal of the growth substrate
Abstract
LIGHT EMITTING DIODES WITH INCREASED
LIGHT EMISSION EFFICIENCY
Abstract of the Disclosure A GaAs light emitting diode is given an increased light emission efficiency by randomly roughening the surface through which the light issues and by forming a metal contact layer on the back surface, the metal contact layer forming an optical mirror for reflecting any light impinging thereon.
- i -
LIGHT EMISSION EFFICIENCY
Abstract of the Disclosure A GaAs light emitting diode is given an increased light emission efficiency by randomly roughening the surface through which the light issues and by forming a metal contact layer on the back surface, the metal contact layer forming an optical mirror for reflecting any light impinging thereon.
- i -
Description
This invention relates to the improvement of light emission efficiency of light emitting diodes (LED`s) and particularly in relation to coupling to optical fibres.
In semiconductor LED's, with light being emitted in a direction normal to the plane of the active layer or light emitting layer, the vast majo~ity of the light produced is lost by internal absorption. Thus, for example, with GaAlAs material, the critical angle of emission is about 17 from the axis normal to the light emitting layer. In a device having parallel faces, any rays encountering the upper surface at an angle greater than this critical angle are reflected back into the device. There-after, the rays will always encounter the surface at the same angle and will never exit, being finally absorbed.
The present invention relates to the preparation of the outer surface of the device, at the light emittlng region, such that a ray encountering this surface at an angle greater than the critical angle is reflected but is capable of encountering this outer surface, after one or more reflections, at an angle less than the critical angle. Improvements in efficiency between 50% and 150% have been achieved.-In a particular application of the invention,the surface of the device is roughened, as by etching.
In its broadest aspect the invention comprises a diode having a First confining layer of GaAlAs, an active layer of GaAs and a second confining layer of GaAlAs in a sandwich formation, the active layer between the confining layers, a light emission surface on one of the confining layers, the surface of random roughness, and means for applying a voltage bias to the diode to produce a light emitting area aligned with the light 3~ emission surface, the means for applying the bias including a metal contact layer on the surface of the other confining layer, 1~58732 the metal contact layer forming a mirror aligned with the light emitting area.
Particularly the layers are on a substrate with an aperture therethrough to the one conFining layer, the l;ght emission surface aligned with the aperture, and said metal contac~
layer is formed over an bptically transparent oxide insulating layer, the metal contact layer in contact with the other confining layer through an aperture in the oxide layer and aligned with the aperture in the substrate.
The invention will be readily understood by the following description in conjunction with the accompanying ;: , .
diagrammatic drawings, in which:-Figure 1 is a cross-section through an LED
illustrating the critical angle, Figure 2 is a cross-section through an LED, similar to that in Figure 1, but illustrating a roughened surface at the light emission surface;
Figure 3 is a cross-section through a coupling structure for coupling an optical fibre to an LED.
As illustrated in Figure 1, an LED structure 10 has a light emitting volume or layer 11. The surface through which light emits or issues is indicated at 12. A ray of light 13 emitted from the layer 11 normal to the plane of the layer 11, and the surface 12, will issue from the device. A ray 14 emitted at an angle ~ will also issue from the device - assuming ~ to be the critical angle, as will any ray between these two rays 13 and 14, for example ray 15. Any ray emitted from layer 11 at an angle greater than ~, for example ray 16, will be internally reflected and will never meet the surface 12 at a different angle, however 3~ many times it is reflected. It is eventually internally absorbed.
Figure 2 illustrates a device or structure 20, , ... . ~ . , ~
, . . . , . , , .... . . ~ : :
1~5~73;~ ;
having the light emitting volume or layer ll and a surface 21 through which light emits or issues. The surface 21 is roughened to give a non-regular or haphazzard profile, viewed in cross-section. By this means~ a ray which would not issue through a flat service can possibly encounter the surface at an angle less than the critical angle - as for example ray 23. A ray encountering the surface 12 at an angle greater than the critical angle is reflected to the rear surface 24 and then reflected to the surface 21 and this time can possibly encounter the surface at an angle less than the crit1cal angle - for example as ray 25. The roughness of surface 21 is shown exaggerated to illustrate the basic feature of the invention.
Figure 3 illustrates in more detail, a particular embodiment of the invention, in relation to the coupling of the light emitted into an optical fibre. A substrate 30 of semi-conductor material, in the present example GaAs, has a plurality of layers formed thereon, as by epitaxial growth, the layers in sequence from the substrate 30 being a first confining layer 31 of GaAlAs, an active layer 32 of GaAs and a second confining layer 33 of GaAlAs. The conductivity types are such that the substrate 30 and first con~ining layer 31 are the same type, the active layer 32 can be the same or opposite type as the substrate and first confining layer, and the second confining layer is of the opposite conductivity type to that of the substrate and First confining layer. Thus, for example, substrate 30 and first confining layer 31 are of n-type, active layer 32 is n-or p-type, and the second confining layer 33 is p-type. The two confining layers 31 and 33 and the active layer 32 are doped to suitable levels, as is well known. For example the confining layers can 3~ be doped to a level of 1018, while the active layer 32 can be `~
doped to a level of, for example between 1017 and 1018. The .
`'.. ,.' ' :' -5~ 7 3Z
confin;ng layers 31 and 33 contain aluminum to a predeterminedvalue while the active layer 32 may or may not include aluminum.
If aluminum is included it is at a significantly lower level than that of the aluminum contact of the confining layers - as is conventional.
After formation of the layers 31, 3Z and 33, the substrate 30 is masked and etched - typically by photolithographic etching techniques - to produce a hole or aperture 3~ through the substrate down to the sur~ace of layer 31. A typical etchant is 25 parts of H202 to 1 part of NH40H. A layer of metal oxide 35 is then formed on the surface of layer 33. An aperture 36 is formed in the oxide layer 35 axially aligned with the hole 34 in the substrate. The aperture 36 can be formed by masking before forming the layer 35, or by forming the layer 35 right across the surface of layer 33, and then photolithographically etching the aperture. A metal contact layer 37 is then formed over the oxide layer and extending into the aperture 36 and into contact with the layer 33. Also a contact layer 38 is formed on the substrate 30.
Finally, the surface 39 of the layer 31 exposed at the bottom of the hole 34 is roughened, by etching, possible etchants including 30/10/3(CH3COOH - HN03 - HF) for forty seconds at 25C. This etchant does not attack gold contacts on the device. Another etchant is KI/I2 for thirty seconds at 60C, but this will attack gold contacts.
As a result of current spreading in layers 31, 32 and 33, the emitting area 40 is larger than the aperture 36 by an annulus 41. The combination of metal layer 37 cGvering the oxide layer 35 which surrounds the aperture 36 forms a highly effective mirror for light which is emitted by the emitting area 40. In ;
particular, a highly efficient mirror exists in the annular region 44, for light which is emitted at the annular emitting region 41, .
' : ',' . , , ~ . ~ . . . . . . .
~15873~
normal or near normal to the plane of the emitting area 40. The metal contact layer 37 in direct contact with layer 33 also acts as a partial mirror, reFlecting rays which encounter it back to wards the surface 39.
The emitting area 40 is designed to be smaller than the hole 34. The core 42 of the optical fibre 43 is positioned `
opposite to the emitting area 40. In general, the core of the fibre is larger than the emitting area 40.
A particularly useful ratio of emitter diameter to fibre core diameter is 60/80, a typical size being a 60 ~m emitter region 40 and a 80 ~m diameter for the light transmitting fibre core 42. However the invention is applicable to various fibre diameters, and fibres with diameters of 125 ~m and 52 ~m have been used. The numerical apertures of such fibres can be of differing values also.
Typical results for a number of devices have shown efficiency increases of up to 150%. It is believed that this large increase in efficiency can be attributed to the comb;nations of the roughened emission surface and the use of a reflecting surface at the back of the device. Hitherto, it has been considered that, in contrast with the situation which exists LED's which emit visible light, i.e. those made from GaP, the absorption characteristics of GaAlAs are such that most light emission from a device occurs at the first encounter between directly emitted rays and the emission surfaces, i.e. rays `;
emitted toward the emission surface, and that any rays reflected back into the device woùld be absorbed. Any rays emitted rear- -wardly, that is away from the emission surface, were assumed to -be absorbed before they would be reflected back toward the 3~ emission surface, or would be absorbed aFter such reflection but before reaching the emission surface.
"
, , , .. ,. " ., . ,:, . . ' , ': ' . , .:
73;2 However, the provision of the reflecting surface, formed by the metal/metal oxide interface, has been found to increase emission, and that rays emitting in directions relative -to the emission surface, other than at or below the critical angle, can be reflected back to the em;ssion surface. Also rays -reflected from the emission surface can "bounce" back and such paths can indicate a number of `'bounces". The rough emission surface increases the likelihood that such reflected rays will encounter the emission surface at an angle at - or less than the 10 critical angle.
To obtain high coupling efficiency into the fibres 42, an index matching fluid can be positioned in the aperture 34, between the end of the fibre 42 and the sur-face 39. e .. . , ............................. ..
- . ,
In semiconductor LED's, with light being emitted in a direction normal to the plane of the active layer or light emitting layer, the vast majo~ity of the light produced is lost by internal absorption. Thus, for example, with GaAlAs material, the critical angle of emission is about 17 from the axis normal to the light emitting layer. In a device having parallel faces, any rays encountering the upper surface at an angle greater than this critical angle are reflected back into the device. There-after, the rays will always encounter the surface at the same angle and will never exit, being finally absorbed.
The present invention relates to the preparation of the outer surface of the device, at the light emittlng region, such that a ray encountering this surface at an angle greater than the critical angle is reflected but is capable of encountering this outer surface, after one or more reflections, at an angle less than the critical angle. Improvements in efficiency between 50% and 150% have been achieved.-In a particular application of the invention,the surface of the device is roughened, as by etching.
In its broadest aspect the invention comprises a diode having a First confining layer of GaAlAs, an active layer of GaAs and a second confining layer of GaAlAs in a sandwich formation, the active layer between the confining layers, a light emission surface on one of the confining layers, the surface of random roughness, and means for applying a voltage bias to the diode to produce a light emitting area aligned with the light 3~ emission surface, the means for applying the bias including a metal contact layer on the surface of the other confining layer, 1~58732 the metal contact layer forming a mirror aligned with the light emitting area.
Particularly the layers are on a substrate with an aperture therethrough to the one conFining layer, the l;ght emission surface aligned with the aperture, and said metal contac~
layer is formed over an bptically transparent oxide insulating layer, the metal contact layer in contact with the other confining layer through an aperture in the oxide layer and aligned with the aperture in the substrate.
The invention will be readily understood by the following description in conjunction with the accompanying ;: , .
diagrammatic drawings, in which:-Figure 1 is a cross-section through an LED
illustrating the critical angle, Figure 2 is a cross-section through an LED, similar to that in Figure 1, but illustrating a roughened surface at the light emission surface;
Figure 3 is a cross-section through a coupling structure for coupling an optical fibre to an LED.
As illustrated in Figure 1, an LED structure 10 has a light emitting volume or layer 11. The surface through which light emits or issues is indicated at 12. A ray of light 13 emitted from the layer 11 normal to the plane of the layer 11, and the surface 12, will issue from the device. A ray 14 emitted at an angle ~ will also issue from the device - assuming ~ to be the critical angle, as will any ray between these two rays 13 and 14, for example ray 15. Any ray emitted from layer 11 at an angle greater than ~, for example ray 16, will be internally reflected and will never meet the surface 12 at a different angle, however 3~ many times it is reflected. It is eventually internally absorbed.
Figure 2 illustrates a device or structure 20, , ... . ~ . , ~
, . . . , . , , .... . . ~ : :
1~5~73;~ ;
having the light emitting volume or layer ll and a surface 21 through which light emits or issues. The surface 21 is roughened to give a non-regular or haphazzard profile, viewed in cross-section. By this means~ a ray which would not issue through a flat service can possibly encounter the surface at an angle less than the critical angle - as for example ray 23. A ray encountering the surface 12 at an angle greater than the critical angle is reflected to the rear surface 24 and then reflected to the surface 21 and this time can possibly encounter the surface at an angle less than the crit1cal angle - for example as ray 25. The roughness of surface 21 is shown exaggerated to illustrate the basic feature of the invention.
Figure 3 illustrates in more detail, a particular embodiment of the invention, in relation to the coupling of the light emitted into an optical fibre. A substrate 30 of semi-conductor material, in the present example GaAs, has a plurality of layers formed thereon, as by epitaxial growth, the layers in sequence from the substrate 30 being a first confining layer 31 of GaAlAs, an active layer 32 of GaAs and a second confining layer 33 of GaAlAs. The conductivity types are such that the substrate 30 and first con~ining layer 31 are the same type, the active layer 32 can be the same or opposite type as the substrate and first confining layer, and the second confining layer is of the opposite conductivity type to that of the substrate and First confining layer. Thus, for example, substrate 30 and first confining layer 31 are of n-type, active layer 32 is n-or p-type, and the second confining layer 33 is p-type. The two confining layers 31 and 33 and the active layer 32 are doped to suitable levels, as is well known. For example the confining layers can 3~ be doped to a level of 1018, while the active layer 32 can be `~
doped to a level of, for example between 1017 and 1018. The .
`'.. ,.' ' :' -5~ 7 3Z
confin;ng layers 31 and 33 contain aluminum to a predeterminedvalue while the active layer 32 may or may not include aluminum.
If aluminum is included it is at a significantly lower level than that of the aluminum contact of the confining layers - as is conventional.
After formation of the layers 31, 3Z and 33, the substrate 30 is masked and etched - typically by photolithographic etching techniques - to produce a hole or aperture 3~ through the substrate down to the sur~ace of layer 31. A typical etchant is 25 parts of H202 to 1 part of NH40H. A layer of metal oxide 35 is then formed on the surface of layer 33. An aperture 36 is formed in the oxide layer 35 axially aligned with the hole 34 in the substrate. The aperture 36 can be formed by masking before forming the layer 35, or by forming the layer 35 right across the surface of layer 33, and then photolithographically etching the aperture. A metal contact layer 37 is then formed over the oxide layer and extending into the aperture 36 and into contact with the layer 33. Also a contact layer 38 is formed on the substrate 30.
Finally, the surface 39 of the layer 31 exposed at the bottom of the hole 34 is roughened, by etching, possible etchants including 30/10/3(CH3COOH - HN03 - HF) for forty seconds at 25C. This etchant does not attack gold contacts on the device. Another etchant is KI/I2 for thirty seconds at 60C, but this will attack gold contacts.
As a result of current spreading in layers 31, 32 and 33, the emitting area 40 is larger than the aperture 36 by an annulus 41. The combination of metal layer 37 cGvering the oxide layer 35 which surrounds the aperture 36 forms a highly effective mirror for light which is emitted by the emitting area 40. In ;
particular, a highly efficient mirror exists in the annular region 44, for light which is emitted at the annular emitting region 41, .
' : ',' . , , ~ . ~ . . . . . . .
~15873~
normal or near normal to the plane of the emitting area 40. The metal contact layer 37 in direct contact with layer 33 also acts as a partial mirror, reFlecting rays which encounter it back to wards the surface 39.
The emitting area 40 is designed to be smaller than the hole 34. The core 42 of the optical fibre 43 is positioned `
opposite to the emitting area 40. In general, the core of the fibre is larger than the emitting area 40.
A particularly useful ratio of emitter diameter to fibre core diameter is 60/80, a typical size being a 60 ~m emitter region 40 and a 80 ~m diameter for the light transmitting fibre core 42. However the invention is applicable to various fibre diameters, and fibres with diameters of 125 ~m and 52 ~m have been used. The numerical apertures of such fibres can be of differing values also.
Typical results for a number of devices have shown efficiency increases of up to 150%. It is believed that this large increase in efficiency can be attributed to the comb;nations of the roughened emission surface and the use of a reflecting surface at the back of the device. Hitherto, it has been considered that, in contrast with the situation which exists LED's which emit visible light, i.e. those made from GaP, the absorption characteristics of GaAlAs are such that most light emission from a device occurs at the first encounter between directly emitted rays and the emission surfaces, i.e. rays `;
emitted toward the emission surface, and that any rays reflected back into the device woùld be absorbed. Any rays emitted rear- -wardly, that is away from the emission surface, were assumed to -be absorbed before they would be reflected back toward the 3~ emission surface, or would be absorbed aFter such reflection but before reaching the emission surface.
"
, , , .. ,. " ., . ,:, . . ' , ': ' . , .:
73;2 However, the provision of the reflecting surface, formed by the metal/metal oxide interface, has been found to increase emission, and that rays emitting in directions relative -to the emission surface, other than at or below the critical angle, can be reflected back to the em;ssion surface. Also rays -reflected from the emission surface can "bounce" back and such paths can indicate a number of `'bounces". The rough emission surface increases the likelihood that such reflected rays will encounter the emission surface at an angle at - or less than the 10 critical angle.
To obtain high coupling efficiency into the fibres 42, an index matching fluid can be positioned in the aperture 34, between the end of the fibre 42 and the sur-face 39. e .. . , ............................. ..
- . ,
Claims (5)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:-
1. A light emitting diode comprising:-a GaAs substrate of one conductivity type and having two parallel major surfaces;
a first confining layer of GaAlAs on one of said major surfaces of said substrate and of the same conductivity type as said substrate;
an active layer of GaAs material on said first confining layer, of either conductivity type;
a second confining layer of GaAlAs on said active layer and of a conductivity type opposite to that of said first confining layer, said active layer forming a p-n junction with one of said confining layers;
a layer of optically transparent insulating oxide on said second confining layer, said oxide layer defining an aperture therein, a metal contact layer on said metal oxide layer, said contact layer extending into said aperture in said metal oxide layer and into contact with said second confining layer to define a light emitting area in said active layer in alignment with and larger than said aperture;
an aperture through said substrate to said first confining layer, to define a light emission surface aligned with said light emitting area, said light emission surface of random roughness and at least as large as said light emitting area;
said contact layer a metal contact layer to form a mirror on said metal oxide layer at least for that area around said aperture in said metal oxide layer in alignment with that part of said light emitting area extending beyond said aperture in said metal oxide layer; and a further contact layer on the other surface of said substrate;
whereby on application of a voltage bias to said p-n junction, light is emitted from said light emitting area and issues through said light emission surface.
a first confining layer of GaAlAs on one of said major surfaces of said substrate and of the same conductivity type as said substrate;
an active layer of GaAs material on said first confining layer, of either conductivity type;
a second confining layer of GaAlAs on said active layer and of a conductivity type opposite to that of said first confining layer, said active layer forming a p-n junction with one of said confining layers;
a layer of optically transparent insulating oxide on said second confining layer, said oxide layer defining an aperture therein, a metal contact layer on said metal oxide layer, said contact layer extending into said aperture in said metal oxide layer and into contact with said second confining layer to define a light emitting area in said active layer in alignment with and larger than said aperture;
an aperture through said substrate to said first confining layer, to define a light emission surface aligned with said light emitting area, said light emission surface of random roughness and at least as large as said light emitting area;
said contact layer a metal contact layer to form a mirror on said metal oxide layer at least for that area around said aperture in said metal oxide layer in alignment with that part of said light emitting area extending beyond said aperture in said metal oxide layer; and a further contact layer on the other surface of said substrate;
whereby on application of a voltage bias to said p-n junction, light is emitted from said light emitting area and issues through said light emission surface.
2. A light emitting diode as claimed in claim 1, said aperture in said substrate larger than said light emitting area, and including an optical fibre positioned in said aperture in said substrate, the light conducting core of said fibre aligned with said light emitting area, the end surface of said fibre in close contact with said light emission surface.
3. A method of producing a light emitting diode having increased light emission efficiency, comprising:-sequentially growing three epitaxial layers, a first confining layer of GaAlAs semiconductor material of a first conductivity type, an active layer of GaAs semiconductor material of either conductivity type and a second confining layer of GaAlAs semiconductor material of a conductivity type opposite to that of said first confining layer, a p-n junction formed between the active layer and one of said confining layers;
forming contacts for the application of a voltage bias across said p-n junction to form a light emitting area;
etching the surface of one of said confining layers to form a light emission surface aligned with said light emitting area, said light emission surface of random roughness.
forming contacts for the application of a voltage bias across said p-n junction to form a light emitting area;
etching the surface of one of said confining layers to form a light emission surface aligned with said light emitting area, said light emission surface of random roughness.
4. A method as claimed in claim 3, wherein said first confining layer is grown on one surface of a GaAs substrate of the same conductivity type as said first confining layer, further comprising:
forming a layer of optically transparent insulating oxide on the surface of said second confining layer, said oxide layer defining an aperture extending through to said surface of said second confining layer;
forming a metal contact layer on said oxide layer, said metal contact layer extending into said aperture into contact with said second confining layer, photolithographically etching an aperture through said substrate to said first confining layer to expose the surface of said first confining layer to form a light emission surface;
forming a contact layer on said substrate, said metal contact layer in said aperture in said oxide layer and said contact layer on said substrate defining said light emitting area, said area larger than said aperture in said oxide layer, said metal contact layer on said oxide layer around the periphery of said aperture in said oxide layer forming a mirror aligned at least with that part of the light emitting area extending beyond said aperture in said oxide layer;
etching said exposed surface of said first confining layer to randomly roughen said light emission surface.
forming a layer of optically transparent insulating oxide on the surface of said second confining layer, said oxide layer defining an aperture extending through to said surface of said second confining layer;
forming a metal contact layer on said oxide layer, said metal contact layer extending into said aperture into contact with said second confining layer, photolithographically etching an aperture through said substrate to said first confining layer to expose the surface of said first confining layer to form a light emission surface;
forming a contact layer on said substrate, said metal contact layer in said aperture in said oxide layer and said contact layer on said substrate defining said light emitting area, said area larger than said aperture in said oxide layer, said metal contact layer on said oxide layer around the periphery of said aperture in said oxide layer forming a mirror aligned at least with that part of the light emitting area extending beyond said aperture in said oxide layer;
etching said exposed surface of said first confining layer to randomly roughen said light emission surface.
5. A method as claimed in claim 4, including etching said aperture through said substrate to a size larger than said light emitting area, and positioning an optical fibre in said aperture through said substrate.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA254,639A CA1058732A (en) | 1976-06-11 | 1976-06-11 | Light emitting diodes with increased light emission efficiency |
| DE19772719567 DE2719567A1 (en) | 1976-06-11 | 1977-05-02 | LIGHT EMITTING DIODE WITH ENHANCED LIGHT EMISSION EFFECTIVENESS |
| NL7705246A NL7705246A (en) | 1976-06-11 | 1977-05-12 | LIGHT-EMITTING DIODE AND METHOD OF MANUFACTURING IT. |
| JP6054177A JPS52152187A (en) | 1976-06-11 | 1977-05-26 | Light emitting diode having increased light emitting efficiency and method of producing same |
| SE7706625A SE7706625L (en) | 1976-06-11 | 1977-06-07 | LIGHT EMITTING DIOD |
| FR7717579A FR2354638A1 (en) | 1976-06-11 | 1977-06-08 | Light emitting diode contg. metal contact layer - forming an optical mirror providing high coupling efficiency with optical fibres (NL 13.12.77) |
| ES459664A ES459664A1 (en) | 1976-06-11 | 1977-06-10 | Light emitting diode having increased light emitting efficiency and method of producing same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA254,639A CA1058732A (en) | 1976-06-11 | 1976-06-11 | Light emitting diodes with increased light emission efficiency |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1058732A true CA1058732A (en) | 1979-07-17 |
Family
ID=4106191
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA254,639A Expired CA1058732A (en) | 1976-06-11 | 1976-06-11 | Light emitting diodes with increased light emission efficiency |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS52152187A (en) |
| CA (1) | CA1058732A (en) |
| DE (1) | DE2719567A1 (en) |
| ES (1) | ES459664A1 (en) |
| FR (1) | FR2354638A1 (en) |
| NL (1) | NL7705246A (en) |
| SE (1) | SE7706625L (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6140248A (en) * | 1995-02-23 | 2000-10-31 | Siemens Aktiengesellschaft | Process for producing a semiconductor device with a roughened semiconductor surface |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54142988A (en) * | 1978-04-28 | 1979-11-07 | Hitachi Ltd | Photo semiconductor device |
| FR2466866A1 (en) * | 1979-10-05 | 1981-04-10 | Thomson Csf | METHOD OF COUPLING BETWEEN AN OPTICAL FIBER AND AN OPTOELECTRONIC DIODE, AND A TRANSMITTING OR RECEPTION HEAD, REALIZED BY THIS METHOD |
| CA1139412A (en) * | 1980-09-10 | 1983-01-11 | Northern Telecom Limited | Light emitting diodes with high external quantum efficiency |
| JPS5825053U (en) * | 1981-08-11 | 1983-02-17 | 住友電気工業株式会社 | Hybrid IC |
| DE3605019A1 (en) * | 1986-02-18 | 1987-08-20 | Messerschmitt Boelkow Blohm | Integrated light-emitting diode for optical-fibre transmission lines and method of producing it |
| DE4218806A1 (en) * | 1992-06-06 | 1993-12-09 | Telefunken Microelectron | Mesa LED with n-doped semiconductor substrate - has depressions formed over surface of p-doped epitaxial layer, pref. in edge region and extending to mesa flank |
| DE4305296C3 (en) * | 1993-02-20 | 1999-07-15 | Vishay Semiconductor Gmbh | Method of manufacturing a radiation emitting diode |
| DE19537544A1 (en) * | 1995-10-09 | 1997-04-10 | Telefunken Microelectron | Luminescence diode |
| DE19537545A1 (en) | 1995-10-09 | 1997-04-10 | Telefunken Microelectron | Luminescence diode manufacturing method with layer group contg. pre-junction |
-
1976
- 1976-06-11 CA CA254,639A patent/CA1058732A/en not_active Expired
-
1977
- 1977-05-02 DE DE19772719567 patent/DE2719567A1/en active Pending
- 1977-05-12 NL NL7705246A patent/NL7705246A/en not_active Application Discontinuation
- 1977-05-26 JP JP6054177A patent/JPS52152187A/en active Pending
- 1977-06-07 SE SE7706625A patent/SE7706625L/en unknown
- 1977-06-08 FR FR7717579A patent/FR2354638A1/en not_active Withdrawn
- 1977-06-10 ES ES459664A patent/ES459664A1/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6140248A (en) * | 1995-02-23 | 2000-10-31 | Siemens Aktiengesellschaft | Process for producing a semiconductor device with a roughened semiconductor surface |
| US6309953B1 (en) | 1995-02-23 | 2001-10-30 | Siemens Aktiengesellschaft | Process for producing a semiconductor device with a roughened semiconductor surface |
Also Published As
| Publication number | Publication date |
|---|---|
| NL7705246A (en) | 1977-12-13 |
| JPS52152187A (en) | 1977-12-17 |
| SE7706625L (en) | 1977-12-12 |
| ES459664A1 (en) | 1978-04-16 |
| DE2719567A1 (en) | 1977-12-22 |
| FR2354638A1 (en) | 1978-01-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0047591B1 (en) | Light emitting diodes with high external quantum efficiency | |
| US3981023A (en) | Integral lens light emitting diode | |
| US6015719A (en) | Transparent substrate light emitting diodes with directed light output | |
| KR101211864B1 (en) | Light-emitting devices having an antireflective layer that has a graded index of refraction and methods of forming the same | |
| US5793062A (en) | Transparent substrate light emitting diodes with directed light output | |
| KR100745229B1 (en) | Improved light extraction from a semiconductor light-emitting device via chip shaping | |
| US3914137A (en) | Method of manufacturing a light coupled monolithic circuit by selective epitaxial deposition | |
| US6063643A (en) | Surface-emission type light-emitting diode and fabrication process thereof | |
| JP3531722B2 (en) | Light emitting diode manufacturing method | |
| JP3312049B2 (en) | Semiconductor light emitting device | |
| US6083769A (en) | Method for producing a light-emitting diode | |
| US4279690A (en) | High-radiance emitters with integral microlens | |
| US5705834A (en) | Increased efficiency LED | |
| US20030141496A1 (en) | Semiconductor chip for optoelectronics | |
| CA1058732A (en) | Light emitting diodes with increased light emission efficiency | |
| JP2015099946A (en) | Led and method of assembling led | |
| EP0977277A1 (en) | Devices for emitting radiation with a high efficiency and a method for fabricating such devices | |
| EP0977280A2 (en) | Devices for emitting radiation with a high efficiency and a method for fabricating such devices | |
| US3699407A (en) | Electro-optical coupled-pair using a schottky barrier diode detector | |
| US4094752A (en) | Method of manufacturing opto-electronic devices | |
| JP2003179255A (en) | Method of selectively providing quantum well in flip chip light emitting diode for improving light extraction | |
| JPS59205774A (en) | Semiconductor light-emitting element | |
| US3821616A (en) | Monolithic semiconductor display devices | |
| KR100413435B1 (en) | Light Emitting Diode and Fabrication Method for the same | |
| JP3290640B2 (en) | Method of manufacturing semiconductor light emitting device having enhanced external quantum efficiency and method of roughening semiconductor compound |