Patent
US 8,389,305Techniques of Forming Ohmic Contacts on GaN Light Emitting Diodes
Andrew J. Felker, Nicholas Andrew Vickers
Soraa, Inc.·US
Copyright © 2026 Matter42. All rights reserved.
Patent
Atlas literature
Patent
US 8,389,305Patent drawings and their descriptions. Click a drawing to enlarge it.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A method of forming ohmic contacts on a light emitting diode having a double hetero-structure configuration, the method comprising: forming an active layer on a gallium nitride substrate, the gallium nitride substrate is GaN; depositing a layer of p-type gallium nitride upon the active layer, the p-type la yer comprising magnesium; providing an acid containing solution comprising nitric acid, hydrochloric acid, and water; exposing a surface of said p-type gallium nitride to the an-acid-containing solution, forming a cleaned surface; subjecting the cleaned surface to a buffered oxide etch process, forming an etched surface, the buffered oxide etch process comprising hydrofluoric acid and ammonium fluoride; and generating, upon the etched surface, a metal stack including a layer of silver and a lav er of platinum; and segm entin g an LED from the GaN substrate and overlying la y ers using a laser.
The method as recited in claim 1 wherein the etched surface is free from contaminants e xposing fther includes priding ni aci hyd roc hlo ric acid an d wate* r i n said a cid con tai nin g s oltin
The method as recited in claim 1 wherein expesmg selt4ion-wi4th- said acid-containing solution consisting essentially of 15 % of said nitric acid by weight, 27 % of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 1 wherein generating further includes depositing said layer of silver between the la y er twe-layef s of platinum and another l ay er of platinum.
The method as recited in claim 1 further including producing a patterned photo resist on said surface followed by deposition of said metal stack.
The method as recited in claim 1 further including producing a patterned photo resist by covering a sub-portion of said cleaned surface with remaining regions of said cleaned surface being exposed followed by exposing said surface to said buffered oxide etch process.
The method as recited in claim 1 further including producing a patterned photo resist on said surface followed by depositing said metal stack on said patterned photo resist following exposing said cleaned surface to said buffered oxide etch process.
The method as recited in claim 1 wherein depositing further includes providing said layer with a p-type dopant concentration of 1 e20 cm⁻³.
The method of claim 1, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 1, wherein the active layer comprises one or more quantum wells.
The method of claim 1, wherein the metal stack comprises three separate metal layers.
A method of forming ohmic contacts on a light emitting diode comprising: forming an active la v er on a gallium nitride substrate, the gallium nitride substrate is GaN; depositing a lay er of p-type gallium nitride upon the active la ver; providing an acid containing solution comprising nitric acid, hydrochloric acid, and water; exposing a surface of said p-type gallium nitride to the acid-containing solution, forming a cleaned surface; 4 PATENT Attorney Docket No. 91756-834248(014510US) subjecting the cleaned surface to a buffered oxide etch process, forming an etched surface, the buffered oxide etch process compris ing h ydrofluoric acid and ammonium fluo ride; generating, upon the etched surface, a metal stack including a la y er of silver and a lav er of platinum; and producing a patterned photo resist on said surface following deposition of said metal stack on said patterned photo resist followed by exposing said surface to said buffered oxide etch process and lifting- off said photo-resist to produce a plurality of spaced-apart metal stacks upon said substrate.
The method of claim 9, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free 7 PATENT Attorney Docket No. 91756-834248(014510US) of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 9, wherein lifting-off exposes the substrate between adjacent metal stacks.
The method of claim 9, wherein the active layer comprises one or more quantum wells.
The method of claim 9, comprising from 2 to 10 quantum wells.
The method of claim 9, wherein the metal stack comprises three separate metal layers.
A method of forming ohmic contacts on a light emitting diode, said method comprising: forming a plurality of quantum wells on a gallium nitride substrate, the plurality of quantum wells comprising InGaN wells configured with ba rri er layers, the barrier lay ers comprising GaN; depositing a layer of p-type gallium nitride upon said quantum wells, the p-type gallium nitride comprising magnesium; exposing a surface of said p-type gallium nitride to an acid-containing solution, forming a cleaned surface; producing a patterned photo resist on said cleaned surface covering sub-portions thereof with remaining regions being exposed; subjecting said remaining regions to a buffered oxide etch process, forming etched regions; generating a metal stack on said etched regions; lifting-off said photo-resist to produce a plurality of spaced-apart metal stacks upon said substrate; and 5 PATENT Attorney Docket No. 91756-834248(014510US) segmenting said substrate using a l aser into a plurality of discrete segments, each of which includes one of said plurality of metal stacks, each of the discrete se gments corresponding to an LED device having ohmic contacts.
The method as recited in claim 11 wherein depositing further includes providing said layer with a p-type dopant concentration of 1 e20 cm⁻³.
The method as recited in claim 11 wherein exposing further includes providing nitric acid, hydrochloric acid and water in said acid-containing solutio n; wherein gallium nitride substrate comprising a surface having a dislocation density below 105 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters
The method as recited in claim 11 wherein exposing f u rther includes providing nitric acid, hydrochloric acid and water in said acid containing solution, with said acid-containing solution consisting essentially of 15 % of said nitric acid by weight, 27 % of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 11 wherein subjecting f u rther includes providing said buffer oxide etch process with components consisting essentially of 2 % hydrofluoric acid by weight and 8.75 % ammonium fluoride by weight.
The method as recited in claim 11 wherein generating further includes depositing a layer of silver between two layers of platinum.
The method of claim 11, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 11, wherein the substrate is exposed between adjacent metal stacks.
The method of claim 11, comprising from 2 to 10 quantum wells.
The method of claim 11, wherein the plurality of spaced-apart metal stacks comprise three separate metal layers.
A method of forming ohmic contacts on a light emitting diode having a double heterostructure confi guration, said method comprising: forming a plurality of quantum wells on a gallium nitride substrate; depositing a layer of gallium nitride upon said quantum wells with a p-type dopant at a concentration of 1 e20 cm- 3, the p-type dopant comprising magnesium; 6 PATENT Attorney Docket No. 91756-834248(014510US) exposing a surface of said p-type gallium nitride to an acid-containing solution, consisting essentially of nitric acid, hydrochloric acid and water, forming a cleaned surface; producing a patterned photo resist on said cleaned surface exposing portions thereof; subjecting said portions to a buffered oxide etch process, forming etched regions; depositing a metal stack on said etched regions; lifting-off said photo resist ph ete-eist to produce a plurality of spaced-apart metal stacks upon said substrate; and segmenting said substrate using a lase r into a plurality of discrete segments, each of which includes one of said plurality of metal stacks, each of the discrete se gments corresponding to an LED device having ohmic contacts.
The method as recited in claim 17 wherein exposing further includes providing said acid-containing solution with 15 % of said nitric acid by weight, 27% of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 17 wherein subjecting further includes providing said buffer oxide etch process with components consisting essentially of 2 % hydrofluoric acid by weight and 8.75 % ammonium fluoride by weight.
The method as recited in claim 17 wherein generating further includes depositing a layer of silver between two layers of platinum.
The method of claim 17, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 17, wherein the substrate is exposed between adjacent metal stacks.
The method of claim 17, comprising from 2 to 10 quantum wells.
Layer stacks claimed or described, ordered top of device to substrate.
GaN light emitting diode with ohmic contacts
Pt/Ag/Pt ohmic contact metal stack
Materials described outside the worked examples.
gallium nitride substrate
GaN
p-type gallium nitride
GaN:Mg
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | 465–700 nm | — |
Thickness |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 8,389,305Patent drawings and their descriptions. Click a drawing to enlarge it.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A method of forming ohmic contacts on a light emitting diode having a double hetero-structure configuration, the method comprising: forming an active layer on a gallium nitride substrate, the gallium nitride substrate is GaN; depositing a layer of p-type gallium nitride upon the active layer, the p-type la yer comprising magnesium; providing an acid containing solution comprising nitric acid, hydrochloric acid, and water; exposing a surface of said p-type gallium nitride to the an-acid-containing solution, forming a cleaned surface; subjecting the cleaned surface to a buffered oxide etch process, forming an etched surface, the buffered oxide etch process comprising hydrofluoric acid and ammonium fluoride; and generating, upon the etched surface, a metal stack including a layer of silver and a lav er of platinum; and segm entin g an LED from the GaN substrate and overlying la y ers using a laser.
The method as recited in claim 1 wherein the etched surface is free from contaminants e xposing fther includes priding ni aci hyd roc hlo ric acid an d wate* r i n said a cid con tai nin g s oltin
The method as recited in claim 1 wherein expesmg selt4ion-wi4th- said acid-containing solution consisting essentially of 15 % of said nitric acid by weight, 27 % of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 1 wherein generating further includes depositing said layer of silver between the la y er twe-layef s of platinum and another l ay er of platinum.
The method as recited in claim 1 further including producing a patterned photo resist on said surface followed by deposition of said metal stack.
The method as recited in claim 1 further including producing a patterned photo resist by covering a sub-portion of said cleaned surface with remaining regions of said cleaned surface being exposed followed by exposing said surface to said buffered oxide etch process.
The method as recited in claim 1 further including producing a patterned photo resist on said surface followed by depositing said metal stack on said patterned photo resist following exposing said cleaned surface to said buffered oxide etch process.
The method as recited in claim 1 wherein depositing further includes providing said layer with a p-type dopant concentration of 1 e20 cm⁻³.
The method of claim 1, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 1, wherein the active layer comprises one or more quantum wells.
The method of claim 1, wherein the metal stack comprises three separate metal layers.
A method of forming ohmic contacts on a light emitting diode comprising: forming an active la v er on a gallium nitride substrate, the gallium nitride substrate is GaN; depositing a lay er of p-type gallium nitride upon the active la ver; providing an acid containing solution comprising nitric acid, hydrochloric acid, and water; exposing a surface of said p-type gallium nitride to the acid-containing solution, forming a cleaned surface; 4 PATENT Attorney Docket No. 91756-834248(014510US) subjecting the cleaned surface to a buffered oxide etch process, forming an etched surface, the buffered oxide etch process compris ing h ydrofluoric acid and ammonium fluo ride; generating, upon the etched surface, a metal stack including a la y er of silver and a lav er of platinum; and producing a patterned photo resist on said surface following deposition of said metal stack on said patterned photo resist followed by exposing said surface to said buffered oxide etch process and lifting- off said photo-resist to produce a plurality of spaced-apart metal stacks upon said substrate.
The method of claim 9, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free 7 PATENT Attorney Docket No. 91756-834248(014510US) of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 9, wherein lifting-off exposes the substrate between adjacent metal stacks.
The method of claim 9, wherein the active layer comprises one or more quantum wells.
The method of claim 9, comprising from 2 to 10 quantum wells.
The method of claim 9, wherein the metal stack comprises three separate metal layers.
A method of forming ohmic contacts on a light emitting diode, said method comprising: forming a plurality of quantum wells on a gallium nitride substrate, the plurality of quantum wells comprising InGaN wells configured with ba rri er layers, the barrier lay ers comprising GaN; depositing a layer of p-type gallium nitride upon said quantum wells, the p-type gallium nitride comprising magnesium; exposing a surface of said p-type gallium nitride to an acid-containing solution, forming a cleaned surface; producing a patterned photo resist on said cleaned surface covering sub-portions thereof with remaining regions being exposed; subjecting said remaining regions to a buffered oxide etch process, forming etched regions; generating a metal stack on said etched regions; lifting-off said photo-resist to produce a plurality of spaced-apart metal stacks upon said substrate; and 5 PATENT Attorney Docket No. 91756-834248(014510US) segmenting said substrate using a l aser into a plurality of discrete segments, each of which includes one of said plurality of metal stacks, each of the discrete se gments corresponding to an LED device having ohmic contacts.
The method as recited in claim 11 wherein depositing further includes providing said layer with a p-type dopant concentration of 1 e20 cm⁻³.
The method as recited in claim 11 wherein exposing further includes providing nitric acid, hydrochloric acid and water in said acid-containing solutio n; wherein gallium nitride substrate comprising a surface having a dislocation density below 105 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters
The method as recited in claim 11 wherein exposing f u rther includes providing nitric acid, hydrochloric acid and water in said acid containing solution, with said acid-containing solution consisting essentially of 15 % of said nitric acid by weight, 27 % of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 11 wherein subjecting f u rther includes providing said buffer oxide etch process with components consisting essentially of 2 % hydrofluoric acid by weight and 8.75 % ammonium fluoride by weight.
The method as recited in claim 11 wherein generating further includes depositing a layer of silver between two layers of platinum.
The method of claim 11, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 11, wherein the substrate is exposed between adjacent metal stacks.
The method of claim 11, comprising from 2 to 10 quantum wells.
The method of claim 11, wherein the plurality of spaced-apart metal stacks comprise three separate metal layers.
A method of forming ohmic contacts on a light emitting diode having a double heterostructure confi guration, said method comprising: forming a plurality of quantum wells on a gallium nitride substrate; depositing a layer of gallium nitride upon said quantum wells with a p-type dopant at a concentration of 1 e20 cm- 3, the p-type dopant comprising magnesium; 6 PATENT Attorney Docket No. 91756-834248(014510US) exposing a surface of said p-type gallium nitride to an acid-containing solution, consisting essentially of nitric acid, hydrochloric acid and water, forming a cleaned surface; producing a patterned photo resist on said cleaned surface exposing portions thereof; subjecting said portions to a buffered oxide etch process, forming etched regions; depositing a metal stack on said etched regions; lifting-off said photo resist ph ete-eist to produce a plurality of spaced-apart metal stacks upon said substrate; and segmenting said substrate using a lase r into a plurality of discrete segments, each of which includes one of said plurality of metal stacks, each of the discrete se gments corresponding to an LED device having ohmic contacts.
The method as recited in claim 17 wherein exposing further includes providing said acid-containing solution with 15 % of said nitric acid by weight, 27% of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 17 wherein subjecting further includes providing said buffer oxide etch process with components consisting essentially of 2 % hydrofluoric acid by weight and 8.75 % ammonium fluoride by weight.
The method as recited in claim 17 wherein generating further includes depositing a layer of silver between two layers of platinum.
The method of claim 17, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 17, wherein the substrate is exposed between adjacent metal stacks.
The method of claim 17, comprising from 2 to 10 quantum wells.
Layer stacks claimed or described, ordered top of device to substrate.
GaN light emitting diode with ohmic contacts
Pt/Ag/Pt ohmic contact metal stack
Materials described outside the worked examples.
gallium nitride substrate
GaN
p-type gallium nitride
GaN:Mg
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | 465–700 nm | — |
Thickness |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 8,389,305Patent drawings and their descriptions. Click a drawing to enlarge it.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A method of forming ohmic contacts on a light emitting diode having a double hetero-structure configuration, the method comprising: forming an active layer on a gallium nitride substrate, the gallium nitride substrate is GaN; depositing a layer of p-type gallium nitride upon the active layer, the p-type la yer comprising magnesium; providing an acid containing solution comprising nitric acid, hydrochloric acid, and water; exposing a surface of said p-type gallium nitride to the an-acid-containing solution, forming a cleaned surface; subjecting the cleaned surface to a buffered oxide etch process, forming an etched surface, the buffered oxide etch process comprising hydrofluoric acid and ammonium fluoride; and generating, upon the etched surface, a metal stack including a layer of silver and a lav er of platinum; and segm entin g an LED from the GaN substrate and overlying la y ers using a laser.
The method as recited in claim 1 wherein the etched surface is free from contaminants e xposing fther includes priding ni aci hyd roc hlo ric acid an d wate* r i n said a cid con tai nin g s oltin
The method as recited in claim 1 wherein expesmg selt4ion-wi4th- said acid-containing solution consisting essentially of 15 % of said nitric acid by weight, 27 % of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 1 wherein generating further includes depositing said layer of silver between the la y er twe-layef s of platinum and another l ay er of platinum.
The method as recited in claim 1 further including producing a patterned photo resist on said surface followed by deposition of said metal stack.
The method as recited in claim 1 further including producing a patterned photo resist by covering a sub-portion of said cleaned surface with remaining regions of said cleaned surface being exposed followed by exposing said surface to said buffered oxide etch process.
The method as recited in claim 1 further including producing a patterned photo resist on said surface followed by depositing said metal stack on said patterned photo resist following exposing said cleaned surface to said buffered oxide etch process.
The method as recited in claim 1 wherein depositing further includes providing said layer with a p-type dopant concentration of 1 e20 cm⁻³.
The method of claim 1, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 1, wherein the active layer comprises one or more quantum wells.
The method of claim 1, wherein the metal stack comprises three separate metal layers.
A method of forming ohmic contacts on a light emitting diode comprising: forming an active la v er on a gallium nitride substrate, the gallium nitride substrate is GaN; depositing a lay er of p-type gallium nitride upon the active la ver; providing an acid containing solution comprising nitric acid, hydrochloric acid, and water; exposing a surface of said p-type gallium nitride to the acid-containing solution, forming a cleaned surface; 4 PATENT Attorney Docket No. 91756-834248(014510US) subjecting the cleaned surface to a buffered oxide etch process, forming an etched surface, the buffered oxide etch process compris ing h ydrofluoric acid and ammonium fluo ride; generating, upon the etched surface, a metal stack including a la y er of silver and a lav er of platinum; and producing a patterned photo resist on said surface following deposition of said metal stack on said patterned photo resist followed by exposing said surface to said buffered oxide etch process and lifting- off said photo-resist to produce a plurality of spaced-apart metal stacks upon said substrate.
The method of claim 9, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free 7 PATENT Attorney Docket No. 91756-834248(014510US) of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 9, wherein lifting-off exposes the substrate between adjacent metal stacks.
The method of claim 9, wherein the active layer comprises one or more quantum wells.
The method of claim 9, comprising from 2 to 10 quantum wells.
The method of claim 9, wherein the metal stack comprises three separate metal layers.
A method of forming ohmic contacts on a light emitting diode, said method comprising: forming a plurality of quantum wells on a gallium nitride substrate, the plurality of quantum wells comprising InGaN wells configured with ba rri er layers, the barrier lay ers comprising GaN; depositing a layer of p-type gallium nitride upon said quantum wells, the p-type gallium nitride comprising magnesium; exposing a surface of said p-type gallium nitride to an acid-containing solution, forming a cleaned surface; producing a patterned photo resist on said cleaned surface covering sub-portions thereof with remaining regions being exposed; subjecting said remaining regions to a buffered oxide etch process, forming etched regions; generating a metal stack on said etched regions; lifting-off said photo-resist to produce a plurality of spaced-apart metal stacks upon said substrate; and 5 PATENT Attorney Docket No. 91756-834248(014510US) segmenting said substrate using a l aser into a plurality of discrete segments, each of which includes one of said plurality of metal stacks, each of the discrete se gments corresponding to an LED device having ohmic contacts.
The method as recited in claim 11 wherein depositing further includes providing said layer with a p-type dopant concentration of 1 e20 cm⁻³.
The method as recited in claim 11 wherein exposing further includes providing nitric acid, hydrochloric acid and water in said acid-containing solutio n; wherein gallium nitride substrate comprising a surface having a dislocation density below 105 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters
The method as recited in claim 11 wherein exposing f u rther includes providing nitric acid, hydrochloric acid and water in said acid containing solution, with said acid-containing solution consisting essentially of 15 % of said nitric acid by weight, 27 % of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 11 wherein subjecting f u rther includes providing said buffer oxide etch process with components consisting essentially of 2 % hydrofluoric acid by weight and 8.75 % ammonium fluoride by weight.
The method as recited in claim 11 wherein generating further includes depositing a layer of silver between two layers of platinum.
The method of claim 11, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 11, wherein the substrate is exposed between adjacent metal stacks.
The method of claim 11, comprising from 2 to 10 quantum wells.
The method of claim 11, wherein the plurality of spaced-apart metal stacks comprise three separate metal layers.
A method of forming ohmic contacts on a light emitting diode having a double heterostructure confi guration, said method comprising: forming a plurality of quantum wells on a gallium nitride substrate; depositing a layer of gallium nitride upon said quantum wells with a p-type dopant at a concentration of 1 e20 cm- 3, the p-type dopant comprising magnesium; 6 PATENT Attorney Docket No. 91756-834248(014510US) exposing a surface of said p-type gallium nitride to an acid-containing solution, consisting essentially of nitric acid, hydrochloric acid and water, forming a cleaned surface; producing a patterned photo resist on said cleaned surface exposing portions thereof; subjecting said portions to a buffered oxide etch process, forming etched regions; depositing a metal stack on said etched regions; lifting-off said photo resist ph ete-eist to produce a plurality of spaced-apart metal stacks upon said substrate; and segmenting said substrate using a lase r into a plurality of discrete segments, each of which includes one of said plurality of metal stacks, each of the discrete se gments corresponding to an LED device having ohmic contacts.
The method as recited in claim 17 wherein exposing further includes providing said acid-containing solution with 15 % of said nitric acid by weight, 27% of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 17 wherein subjecting further includes providing said buffer oxide etch process with components consisting essentially of 2 % hydrofluoric acid by weight and 8.75 % ammonium fluoride by weight.
The method as recited in claim 17 wherein generating further includes depositing a layer of silver between two layers of platinum.
The method of claim 17, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 17, wherein the substrate is exposed between adjacent metal stacks.
The method of claim 17, comprising from 2 to 10 quantum wells.
Layer stacks claimed or described, ordered top of device to substrate.
GaN light emitting diode with ohmic contacts
Pt/Ag/Pt ohmic contact metal stack
Materials described outside the worked examples.
gallium nitride substrate
GaN
p-type gallium nitride
GaN:Mg
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | 465–700 nm | — |
Thickness |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 8,389,305Patent drawings and their descriptions. Click a drawing to enlarge it.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A method of forming ohmic contacts on a light emitting diode having a double hetero-structure configuration, the method comprising: forming an active layer on a gallium nitride substrate, the gallium nitride substrate is GaN; depositing a layer of p-type gallium nitride upon the active layer, the p-type la yer comprising magnesium; providing an acid containing solution comprising nitric acid, hydrochloric acid, and water; exposing a surface of said p-type gallium nitride to the an-acid-containing solution, forming a cleaned surface; subjecting the cleaned surface to a buffered oxide etch process, forming an etched surface, the buffered oxide etch process comprising hydrofluoric acid and ammonium fluoride; and generating, upon the etched surface, a metal stack including a layer of silver and a lav er of platinum; and segm entin g an LED from the GaN substrate and overlying la y ers using a laser.
The method as recited in claim 1 wherein the etched surface is free from contaminants e xposing fther includes priding ni aci hyd roc hlo ric acid an d wate* r i n said a cid con tai nin g s oltin
The method as recited in claim 1 wherein expesmg selt4ion-wi4th- said acid-containing solution consisting essentially of 15 % of said nitric acid by weight, 27 % of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 1 wherein generating further includes depositing said layer of silver between the la y er twe-layef s of platinum and another l ay er of platinum.
The method as recited in claim 1 further including producing a patterned photo resist on said surface followed by deposition of said metal stack.
The method as recited in claim 1 further including producing a patterned photo resist by covering a sub-portion of said cleaned surface with remaining regions of said cleaned surface being exposed followed by exposing said surface to said buffered oxide etch process.
The method as recited in claim 1 further including producing a patterned photo resist on said surface followed by depositing said metal stack on said patterned photo resist following exposing said cleaned surface to said buffered oxide etch process.
The method as recited in claim 1 wherein depositing further includes providing said layer with a p-type dopant concentration of 1 e20 cm⁻³.
The method of claim 1, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 1, wherein the active layer comprises one or more quantum wells.
The method of claim 1, wherein the metal stack comprises three separate metal layers.
A method of forming ohmic contacts on a light emitting diode comprising: forming an active la v er on a gallium nitride substrate, the gallium nitride substrate is GaN; depositing a lay er of p-type gallium nitride upon the active la ver; providing an acid containing solution comprising nitric acid, hydrochloric acid, and water; exposing a surface of said p-type gallium nitride to the acid-containing solution, forming a cleaned surface; 4 PATENT Attorney Docket No. 91756-834248(014510US) subjecting the cleaned surface to a buffered oxide etch process, forming an etched surface, the buffered oxide etch process compris ing h ydrofluoric acid and ammonium fluo ride; generating, upon the etched surface, a metal stack including a la y er of silver and a lav er of platinum; and producing a patterned photo resist on said surface following deposition of said metal stack on said patterned photo resist followed by exposing said surface to said buffered oxide etch process and lifting- off said photo-resist to produce a plurality of spaced-apart metal stacks upon said substrate.
The method of claim 9, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free 7 PATENT Attorney Docket No. 91756-834248(014510US) of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 9, wherein lifting-off exposes the substrate between adjacent metal stacks.
The method of claim 9, wherein the active layer comprises one or more quantum wells.
The method of claim 9, comprising from 2 to 10 quantum wells.
The method of claim 9, wherein the metal stack comprises three separate metal layers.
A method of forming ohmic contacts on a light emitting diode, said method comprising: forming a plurality of quantum wells on a gallium nitride substrate, the plurality of quantum wells comprising InGaN wells configured with ba rri er layers, the barrier lay ers comprising GaN; depositing a layer of p-type gallium nitride upon said quantum wells, the p-type gallium nitride comprising magnesium; exposing a surface of said p-type gallium nitride to an acid-containing solution, forming a cleaned surface; producing a patterned photo resist on said cleaned surface covering sub-portions thereof with remaining regions being exposed; subjecting said remaining regions to a buffered oxide etch process, forming etched regions; generating a metal stack on said etched regions; lifting-off said photo-resist to produce a plurality of spaced-apart metal stacks upon said substrate; and 5 PATENT Attorney Docket No. 91756-834248(014510US) segmenting said substrate using a l aser into a plurality of discrete segments, each of which includes one of said plurality of metal stacks, each of the discrete se gments corresponding to an LED device having ohmic contacts.
The method as recited in claim 11 wherein depositing further includes providing said layer with a p-type dopant concentration of 1 e20 cm⁻³.
The method as recited in claim 11 wherein exposing further includes providing nitric acid, hydrochloric acid and water in said acid-containing solutio n; wherein gallium nitride substrate comprising a surface having a dislocation density below 105 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters
The method as recited in claim 11 wherein exposing f u rther includes providing nitric acid, hydrochloric acid and water in said acid containing solution, with said acid-containing solution consisting essentially of 15 % of said nitric acid by weight, 27 % of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 11 wherein subjecting f u rther includes providing said buffer oxide etch process with components consisting essentially of 2 % hydrofluoric acid by weight and 8.75 % ammonium fluoride by weight.
The method as recited in claim 11 wherein generating further includes depositing a layer of silver between two layers of platinum.
The method of claim 11, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 11, wherein the substrate is exposed between adjacent metal stacks.
The method of claim 11, comprising from 2 to 10 quantum wells.
The method of claim 11, wherein the plurality of spaced-apart metal stacks comprise three separate metal layers.
A method of forming ohmic contacts on a light emitting diode having a double heterostructure confi guration, said method comprising: forming a plurality of quantum wells on a gallium nitride substrate; depositing a layer of gallium nitride upon said quantum wells with a p-type dopant at a concentration of 1 e20 cm- 3, the p-type dopant comprising magnesium; 6 PATENT Attorney Docket No. 91756-834248(014510US) exposing a surface of said p-type gallium nitride to an acid-containing solution, consisting essentially of nitric acid, hydrochloric acid and water, forming a cleaned surface; producing a patterned photo resist on said cleaned surface exposing portions thereof; subjecting said portions to a buffered oxide etch process, forming etched regions; depositing a metal stack on said etched regions; lifting-off said photo resist ph ete-eist to produce a plurality of spaced-apart metal stacks upon said substrate; and segmenting said substrate using a lase r into a plurality of discrete segments, each of which includes one of said plurality of metal stacks, each of the discrete se gments corresponding to an LED device having ohmic contacts.
The method as recited in claim 17 wherein exposing further includes providing said acid-containing solution with 15 % of said nitric acid by weight, 27% of said hydrochloric acid by weight and 58 % of said water by weight.
The method as recited in claim 17 wherein subjecting further includes providing said buffer oxide etch process with components consisting essentially of 2 % hydrofluoric acid by weight and 8.75 % ammonium fluoride by weight.
The method as recited in claim 17 wherein generating further includes depositing a layer of silver between two layers of platinum.
The method of claim 17, wherein the gallium nitride substrate comprises a surface having a dislocation density below 1 05 cm- 2 and is substantially free of low-angle grain boundaries, or tilt boundaries, over a length scale of at least 3 millimeters.
The method of claim 17, wherein the substrate is exposed between adjacent metal stacks.
The method of claim 17, comprising from 2 to 10 quantum wells.
Layer stacks claimed or described, ordered top of device to substrate.
GaN light emitting diode with ohmic contacts
Pt/Ag/Pt ohmic contact metal stack
Materials described outside the worked examples.
gallium nitride substrate
GaN
p-type gallium nitride
GaN:Mg
Additional fabrication and treatment steps described in the patent.
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Thickness | 465–700 nm | — |
Thickness |
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