Patent
US 8,252,662METHOD AND STRUCTURE FOR MANUFACTURE OF LIGHT EMITTING DIODE DEVICES USING BULK GaN
Christiane Poblenz, Mathew C. Schmidt, Daniel F. Feezell, James W. Raring et al.
SORAA, INC.·US
Copyright © 2026 Matter42. All rights reserved.
Patent
Atlas literature
Patent
US 8,252,662Patent drawings and their descriptions. Click a drawing to enlarge it.
Figure 1 is a simplified cross section of a conventional LED.
Figure 2 is a simplified plot comparing light output and luminous efficiency as a function of current for white LED lamps based on YAG:Ce (phosphor) coated conventional flip chip and thin-film flip chip LEDs. As show, a total lumen output of the thin-film flip chip LED lamp exceeds that of the conventional …
Figure 3 is a schematic illustration of a PEC etching setup according to an embodiment of the present invention.
Figures 4(a)-4(g) are simplified process flow of a method for forming an LED device with high extraction efficiency geometry based on bulk GaN substrates, according to a specific embodiment of the present invention.
Figure 5(a)-5(f) are simplified diagrams illustrating a method and process flow for the formation of LED devices with high extraction efficiency geometry based on bulk GaN substrates, according to another specific embodiment of the present invention.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
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A method for fabricating a plurality of light emitting diodes (LEDs) comprising: providing a non-polar or semi-polar bulk crystalline substrate which includes gallium nitride, and which has a front surface and a back surface separated by a first thickness; forming a precursor structure for the LEDs on the substrate by forming an AlGaN filter et c h s t e p layer with a lower A l% percentage than that in the overlyin g layers over the front surface, an n-type layer over the filter et eh-ste p layer, an active region layer over the n-type layer, a p-type layer over the active region layer, and a metallization layer over the p-type layer; removing material from the back surface of the substrate to reduce the substrate to a second thickness; dividing the substrate and overlying layers into separate LED devices; mounting the LED devices to a carrier structure having an upper surface with the metallization layer on each LED device in contact with the carrier structure; and etching, using band g ap-selective photoelectrochemical etchin g, the substrate t o a thickness of 3-4 p m dow n to the etch step lay.
The method of claim 45 wherein the step of dividing the substrate comprises at least one of scribing, dicing, cleaving, and breaking.
The method of claim 45 wherein the step of mounting the LED devices to a carrier structure comprises eutectic bonding.
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The method of claim 52 wherein the n-type layer and the p- type layer each comprise GaN.
A method for fabricating a plurality light emitting diodes (LEDs) comprising: providing a gallium nitride substrate with a non-polar or semi-polar crystallographic orientation, the substrate having a front surface and a back surface separated by a first thickness; forming a precursor structure for the LEDs on the substrate by forming an sacrificial layer over the surface region, an n-type layer over the sacrificial layer, an active region over the n-type layer, a p-type layer over the active region, and a metallization layer over the p-type layer; dividing the precursor structure into separate LEDs by etching channels in the structure which extend through the metallization layer, the p-type layer, the active region, and the n-type layer, to the sacrificial layer; attaching a submount to the metallization layer on the precursor structure; laterally etching the sacrificial layer to enable removal of the substrate; Page 3 of 11 App l e. No. 12/749,476 PATENT Amdt. dated Reply to Office Action on removing the substrate, and dividing the submount and overlying layers into separate LED devices, wherein the step of dividing the precursor structure into separate LEDs by etching channels in the structure further comprises: in a first etching step etching the metallization layer, the p-type layer, and the active region to thereby form mesa structures having sidewalls; and in a second etching step etching the n-type layer.
The method of claim 57 further comprising a step of passivating the sidewalls of the mesa structures before performing the second etching step.
The method of claim 57 wherein the step of laterally etching the sacrificial layer comprises performing a photoelectrochemical etching process.
The method of claim 57 further comprising after the step of removing the substrate, the substrate which has been removed is reused in the step of providing a gallium nitride substrate with a non-polar or semi-polar crystallographic orientation.
The method of claim 57 wherein the sacrificial layer comprises indium gallium.
The method of claim 57 wherein the substrate has a first band gap energy and the sacrificial layer has a second band gap energy less than the first band gap energy.
The method of claim 57 wherein the step of laterally etching the sacrificial layer to enable removal of the substrate comprises performing a photoelectrochemical etching process.
The method of claim 57 wherein the n-type layer and the p- type layer each comprise GaN.
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Layer stacks claimed or described, ordered top of device to substrate.
bulk GaN LED
Materials described outside the worked examples.
gallium nitride bulk crystalline substrate
GaN
AlGaN filter/etch stop layer
AlGaN
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | 200–5000 nm | — |
Thickness |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 8,252,662Patent drawings and their descriptions. Click a drawing to enlarge it.
Figure 1 is a simplified cross section of a conventional LED.
Figure 2 is a simplified plot comparing light output and luminous efficiency as a function of current for white LED lamps based on YAG:Ce (phosphor) coated conventional flip chip and thin-film flip chip LEDs. As show, a total lumen output of the thin-film flip chip LED lamp exceeds that of the conventional …
Figure 3 is a schematic illustration of a PEC etching setup according to an embodiment of the present invention.
Figures 4(a)-4(g) are simplified process flow of a method for forming an LED device with high extraction efficiency geometry based on bulk GaN substrates, according to a specific embodiment of the present invention.
Figure 5(a)-5(f) are simplified diagrams illustrating a method and process flow for the formation of LED devices with high extraction efficiency geometry based on bulk GaN substrates, according to another specific embodiment of the present invention.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
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A method for fabricating a plurality of light emitting diodes (LEDs) comprising: providing a non-polar or semi-polar bulk crystalline substrate which includes gallium nitride, and which has a front surface and a back surface separated by a first thickness; forming a precursor structure for the LEDs on the substrate by forming an AlGaN filter et c h s t e p layer with a lower A l% percentage than that in the overlyin g layers over the front surface, an n-type layer over the filter et eh-ste p layer, an active region layer over the n-type layer, a p-type layer over the active region layer, and a metallization layer over the p-type layer; removing material from the back surface of the substrate to reduce the substrate to a second thickness; dividing the substrate and overlying layers into separate LED devices; mounting the LED devices to a carrier structure having an upper surface with the metallization layer on each LED device in contact with the carrier structure; and etching, using band g ap-selective photoelectrochemical etchin g, the substrate t o a thickness of 3-4 p m dow n to the etch step lay.
The method of claim 45 wherein the step of dividing the substrate comprises at least one of scribing, dicing, cleaving, and breaking.
The method of claim 45 wherein the step of mounting the LED devices to a carrier structure comprises eutectic bonding.
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The method of claim 52 wherein the n-type layer and the p- type layer each comprise GaN.
A method for fabricating a plurality light emitting diodes (LEDs) comprising: providing a gallium nitride substrate with a non-polar or semi-polar crystallographic orientation, the substrate having a front surface and a back surface separated by a first thickness; forming a precursor structure for the LEDs on the substrate by forming an sacrificial layer over the surface region, an n-type layer over the sacrificial layer, an active region over the n-type layer, a p-type layer over the active region, and a metallization layer over the p-type layer; dividing the precursor structure into separate LEDs by etching channels in the structure which extend through the metallization layer, the p-type layer, the active region, and the n-type layer, to the sacrificial layer; attaching a submount to the metallization layer on the precursor structure; laterally etching the sacrificial layer to enable removal of the substrate; Page 3 of 11 App l e. No. 12/749,476 PATENT Amdt. dated Reply to Office Action on removing the substrate, and dividing the submount and overlying layers into separate LED devices, wherein the step of dividing the precursor structure into separate LEDs by etching channels in the structure further comprises: in a first etching step etching the metallization layer, the p-type layer, and the active region to thereby form mesa structures having sidewalls; and in a second etching step etching the n-type layer.
The method of claim 57 further comprising a step of passivating the sidewalls of the mesa structures before performing the second etching step.
The method of claim 57 wherein the step of laterally etching the sacrificial layer comprises performing a photoelectrochemical etching process.
The method of claim 57 further comprising after the step of removing the substrate, the substrate which has been removed is reused in the step of providing a gallium nitride substrate with a non-polar or semi-polar crystallographic orientation.
The method of claim 57 wherein the sacrificial layer comprises indium gallium.
The method of claim 57 wherein the substrate has a first band gap energy and the sacrificial layer has a second band gap energy less than the first band gap energy.
The method of claim 57 wherein the step of laterally etching the sacrificial layer to enable removal of the substrate comprises performing a photoelectrochemical etching process.
The method of claim 57 wherein the n-type layer and the p- type layer each comprise GaN.
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Layer stacks claimed or described, ordered top of device to substrate.
bulk GaN LED
Materials described outside the worked examples.
gallium nitride bulk crystalline substrate
GaN
AlGaN filter/etch stop layer
AlGaN
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | 200–5000 nm | — |
Thickness |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 8,252,662Patent drawings and their descriptions. Click a drawing to enlarge it.
Figure 1 is a simplified cross section of a conventional LED.
Figure 2 is a simplified plot comparing light output and luminous efficiency as a function of current for white LED lamps based on YAG:Ce (phosphor) coated conventional flip chip and thin-film flip chip LEDs. As show, a total lumen output of the thin-film flip chip LED lamp exceeds that of the conventional …
Figure 3 is a schematic illustration of a PEC etching setup according to an embodiment of the present invention.
Figures 4(a)-4(g) are simplified process flow of a method for forming an LED device with high extraction efficiency geometry based on bulk GaN substrates, according to a specific embodiment of the present invention.
Figure 5(a)-5(f) are simplified diagrams illustrating a method and process flow for the formation of LED devices with high extraction efficiency geometry based on bulk GaN substrates, according to another specific embodiment of the present invention.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
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A method for fabricating a plurality of light emitting diodes (LEDs) comprising: providing a non-polar or semi-polar bulk crystalline substrate which includes gallium nitride, and which has a front surface and a back surface separated by a first thickness; forming a precursor structure for the LEDs on the substrate by forming an AlGaN filter et c h s t e p layer with a lower A l% percentage than that in the overlyin g layers over the front surface, an n-type layer over the filter et eh-ste p layer, an active region layer over the n-type layer, a p-type layer over the active region layer, and a metallization layer over the p-type layer; removing material from the back surface of the substrate to reduce the substrate to a second thickness; dividing the substrate and overlying layers into separate LED devices; mounting the LED devices to a carrier structure having an upper surface with the metallization layer on each LED device in contact with the carrier structure; and etching, using band g ap-selective photoelectrochemical etchin g, the substrate t o a thickness of 3-4 p m dow n to the etch step lay.
The method of claim 45 wherein the step of dividing the substrate comprises at least one of scribing, dicing, cleaving, and breaking.
The method of claim 45 wherein the step of mounting the LED devices to a carrier structure comprises eutectic bonding.
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The method of claim 52 wherein the n-type layer and the p- type layer each comprise GaN.
A method for fabricating a plurality light emitting diodes (LEDs) comprising: providing a gallium nitride substrate with a non-polar or semi-polar crystallographic orientation, the substrate having a front surface and a back surface separated by a first thickness; forming a precursor structure for the LEDs on the substrate by forming an sacrificial layer over the surface region, an n-type layer over the sacrificial layer, an active region over the n-type layer, a p-type layer over the active region, and a metallization layer over the p-type layer; dividing the precursor structure into separate LEDs by etching channels in the structure which extend through the metallization layer, the p-type layer, the active region, and the n-type layer, to the sacrificial layer; attaching a submount to the metallization layer on the precursor structure; laterally etching the sacrificial layer to enable removal of the substrate; Page 3 of 11 App l e. No. 12/749,476 PATENT Amdt. dated Reply to Office Action on removing the substrate, and dividing the submount and overlying layers into separate LED devices, wherein the step of dividing the precursor structure into separate LEDs by etching channels in the structure further comprises: in a first etching step etching the metallization layer, the p-type layer, and the active region to thereby form mesa structures having sidewalls; and in a second etching step etching the n-type layer.
The method of claim 57 further comprising a step of passivating the sidewalls of the mesa structures before performing the second etching step.
The method of claim 57 wherein the step of laterally etching the sacrificial layer comprises performing a photoelectrochemical etching process.
The method of claim 57 further comprising after the step of removing the substrate, the substrate which has been removed is reused in the step of providing a gallium nitride substrate with a non-polar or semi-polar crystallographic orientation.
The method of claim 57 wherein the sacrificial layer comprises indium gallium.
The method of claim 57 wherein the substrate has a first band gap energy and the sacrificial layer has a second band gap energy less than the first band gap energy.
The method of claim 57 wherein the step of laterally etching the sacrificial layer to enable removal of the substrate comprises performing a photoelectrochemical etching process.
The method of claim 57 wherein the n-type layer and the p- type layer each comprise GaN.
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Layer stacks claimed or described, ordered top of device to substrate.
bulk GaN LED
Materials described outside the worked examples.
gallium nitride bulk crystalline substrate
GaN
AlGaN filter/etch stop layer
AlGaN
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | 200–5000 nm | — |
Thickness |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 8,252,662Patent drawings and their descriptions. Click a drawing to enlarge it.
Figure 1 is a simplified cross section of a conventional LED.
Figure 2 is a simplified plot comparing light output and luminous efficiency as a function of current for white LED lamps based on YAG:Ce (phosphor) coated conventional flip chip and thin-film flip chip LEDs. As show, a total lumen output of the thin-film flip chip LED lamp exceeds that of the conventional …
Figure 3 is a schematic illustration of a PEC etching setup according to an embodiment of the present invention.
Figures 4(a)-4(g) are simplified process flow of a method for forming an LED device with high extraction efficiency geometry based on bulk GaN substrates, according to a specific embodiment of the present invention.
Figure 5(a)-5(f) are simplified diagrams illustrating a method and process flow for the formation of LED devices with high extraction efficiency geometry based on bulk GaN substrates, according to another specific embodiment of the present invention.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
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A method for fabricating a plurality of light emitting diodes (LEDs) comprising: providing a non-polar or semi-polar bulk crystalline substrate which includes gallium nitride, and which has a front surface and a back surface separated by a first thickness; forming a precursor structure for the LEDs on the substrate by forming an AlGaN filter et c h s t e p layer with a lower A l% percentage than that in the overlyin g layers over the front surface, an n-type layer over the filter et eh-ste p layer, an active region layer over the n-type layer, a p-type layer over the active region layer, and a metallization layer over the p-type layer; removing material from the back surface of the substrate to reduce the substrate to a second thickness; dividing the substrate and overlying layers into separate LED devices; mounting the LED devices to a carrier structure having an upper surface with the metallization layer on each LED device in contact with the carrier structure; and etching, using band g ap-selective photoelectrochemical etchin g, the substrate t o a thickness of 3-4 p m dow n to the etch step lay.
The method of claim 45 wherein the step of dividing the substrate comprises at least one of scribing, dicing, cleaving, and breaking.
The method of claim 45 wherein the step of mounting the LED devices to a carrier structure comprises eutectic bonding.
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The method of claim 52 wherein the n-type layer and the p- type layer each comprise GaN.
A method for fabricating a plurality light emitting diodes (LEDs) comprising: providing a gallium nitride substrate with a non-polar or semi-polar crystallographic orientation, the substrate having a front surface and a back surface separated by a first thickness; forming a precursor structure for the LEDs on the substrate by forming an sacrificial layer over the surface region, an n-type layer over the sacrificial layer, an active region over the n-type layer, a p-type layer over the active region, and a metallization layer over the p-type layer; dividing the precursor structure into separate LEDs by etching channels in the structure which extend through the metallization layer, the p-type layer, the active region, and the n-type layer, to the sacrificial layer; attaching a submount to the metallization layer on the precursor structure; laterally etching the sacrificial layer to enable removal of the substrate; Page 3 of 11 App l e. No. 12/749,476 PATENT Amdt. dated Reply to Office Action on removing the substrate, and dividing the submount and overlying layers into separate LED devices, wherein the step of dividing the precursor structure into separate LEDs by etching channels in the structure further comprises: in a first etching step etching the metallization layer, the p-type layer, and the active region to thereby form mesa structures having sidewalls; and in a second etching step etching the n-type layer.
The method of claim 57 further comprising a step of passivating the sidewalls of the mesa structures before performing the second etching step.
The method of claim 57 wherein the step of laterally etching the sacrificial layer comprises performing a photoelectrochemical etching process.
The method of claim 57 further comprising after the step of removing the substrate, the substrate which has been removed is reused in the step of providing a gallium nitride substrate with a non-polar or semi-polar crystallographic orientation.
The method of claim 57 wherein the sacrificial layer comprises indium gallium.
The method of claim 57 wherein the substrate has a first band gap energy and the sacrificial layer has a second band gap energy less than the first band gap energy.
The method of claim 57 wherein the step of laterally etching the sacrificial layer to enable removal of the substrate comprises performing a photoelectrochemical etching process.
The method of claim 57 wherein the n-type layer and the p- type layer each comprise GaN.
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Layer stacks claimed or described, ordered top of device to substrate.
bulk GaN LED
Materials described outside the worked examples.
gallium nitride bulk crystalline substrate
GaN
AlGaN filter/etch stop layer
AlGaN
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | 200–5000 nm | — |
Thickness |
Related documents with shared materials, methods, properties, or citations.
n-type layer
p-type layer
metallization layer
InGaN
| 3–4 um |
| — |
n-type layer
p-type layer
metallization layer
InGaN
| 3–4 um |
| — |
n-type layer
p-type layer
metallization layer
InGaN
| 3–4 um |
| — |
n-type layer
p-type layer
metallization layer
InGaN
| 3–4 um |
| — |