# US 9,437,783 B2 · Light emitting diode (LED) contact structures and process for fabricating the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,783 B2 - Document ID: US9437783B2 - Status: Granted - Kind: B2 - Application number: 13/466,590 - Filed: 2012-05-08 - Published: 2013-11-14 - Granted: 2016-09-06 - Earliest claimed: 2012-05-08 - Assignees: Cree, Inc. - Applicants: Pritish Kar; David Beardsley Slater, Jr.; Matthew Donofrio; Brad Williams - Inventors: Pritish Kar; David Beardsley Slater, Jr.; Matthew Donofrio; Brad Williams - Web page: https://patentgrep.com/patent/US9437783B2 ## CPC - H10H 20/832: characterised by their material - H10H 20/032: {of electrodes} - H10H 20/82: Roughened surfaces, e.g. at the interface between epitaxial layers - H10H 20/825: containing nitrogen, e.g. GaN - H10H 20/8312: {extending at least partially through the bodies} - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS ## Abstract A light emitting device includes an active layer configured to provide light emission due to carrier recombination therein, a surface on the active layer, and an electrically conductive contact structure on the surface. The contact structure includes at least one plated contact layer. The contact structure may include a sublayer that conforms to the surface roughness of the underlying surface, and the plated contact layer may be substantially free of the surface roughness of the underlying surface. The surface of the plated contact layer may be substantially planar and/or otherwise configured to reflect the light emission from the active layer. Related fabrication methods are also discussed. ## Claims ### Claim 1 A light emitting device, comprising: an active layer configured to provide light emission; a light extraction surface comprising protruding features on the active layer; and an electrically conductive contact structure comprising at least one plated contact layer on the protruding features of the light extraction surface and a conductive seed layer therebetween, wherein a surface of the plated contact layer is substantially free of a surface roughness defined by the protruding features of the light extraction surface, and wherein the surface of the plated contact layer has a greater reflectivity with respect to the light emission than a surface of the conductive seed layer that is opposite the protruding features of the light extraction surface. ### Claim 2 (depends on 1) The device of claim 1, wherein the conductive seed layer comprises at least one sputtered or evaporated layer between the plated contact layer and the protruding features of the light extraction surface on the active layer. ### Claim 3 (depends on 2) The device of claim 2, wherein the conductive seed layer conforms to the surface roughness defined by the protruding features of the light extraction surface on the active layer, and wherein the surface of the plated contact layer is opposite the conductive seed layer. ### Claim 4 (depends on 3) The device of claim 3, wherein a surface roughness of the surface of the conductive seed layer that is opposite to the light extraction surface is more than about 50% of that of the light extraction surface, and wherein a surface roughness of the surface of the plated contact layer is less than about 10% of that of the light extraction surface on the active layer. ### Claim 5 A light emitting device, comprising: an active layer configured to provide light emission; a surface on the active layer; and an electrically conductive contact structure comprising at least one plated contact layer on the surface, wherein a base of the plated contact layer adjacent the active layer is wider than a surface of the plated contact layer opposite the active layer, wherein the surface on the active layer includes a plurality of features protruding therefrom by more than about 0.5 micrometers (μm), and wherein the plated contact layer has a thickness of about 8 micrometers (μm) or less, and wherein a surface of the plated contact layer opposite the active layer has a surface roughness of less than about 10% of that of the surface on the active layer. ### Claim 6 (depends on 1) The device of claim 1, wherein the light extraction surface comprises a surface of an epitaxial layer or a surface of a substrate including the active layer thereon. ### Claim 7 (depends on 2) The device of claim 2, wherein the plated contact layer comprises gold or an alloy thereof. ### Claim 8 (depends on 7) The device of claim 7, wherein the conductive seed layer comprises a layer of gold or an alloy thereof. ### Claim 9 (depends on 8) The device of claim 8, wherein the conductive seed layer further comprises a layer of titanium or an alloy thereof between the layer of gold and the light extraction surface on the active layer. ### Claim 10 (depends on 9) The device of claim 9, wherein the conductive seed layer further comprises a layer of aluminum or an alloy thereof between the titanium layer and the light extraction surface on the active layer. ### Claim 11 (depends on 5) The device of claim 5, wherein the plated contact layer comprises a stack including multiple plated layers. ### Claim 12 (depends on 11) The device of claim 11, wherein the plated contact layer further comprises respective barrier layers between adjacent ones of the multiple plated layers in the stack. ### Claim 13 (depends on 11) The device of claim 11, wherein the multiple plated layers respectively comprise gold, silver, tungsten, palladium, rhenium, copper, titanium, platinum, chromium, nickel, aluminum, and/or alloys thereof. ### Claim 14 (depends on 2) The device of claim 2, wherein the conductive seed layer comprises a stack including multiple layers, and wherein the multiple layers respectively comprise titanium, tungsten, chromium, nickel, platinum, and/or alloys thereof. ### Claim 15 (depends on 1) The device of claim 1, wherein at least one sidewall of the plated contact layer is inclined relative to the light extraction surface on the active layer. ### Claim 16 A light emitting device, comprising: an active layer configured to provide light emission; a surface on the active layer, the surface comprising a plurality of features protruding therefrom; and an electrically conductive contact structure comprising at least one plated contact layer on the protruding features of the surface and a conductive seed layer therebetween, wherein a surface of the plated contact layer opposite the active layer has a surface roughness of less than about 10% of that of the surface on the active layer, wherein the surface of the plated contact layer has a greater reflectivity with respect to the light emission than a surface of the conductive seed layer that is opposite the features protruding from the surface on the active layer, and wherein a base of the plated contact layer adjacent the active layer is wider than the surface of the plated contact layer opposite the active layer. ### Claim 17 (depends on 16) The device of claim 16, wherein the conductive seed layer comprises at least one sputtered or evaporated metal layer between the plated contact layer and the features protruding from the surface on the active layer. ### Claim 18 (depends on 16) The device of claim 16, wherein the conductive seed layer has a thickness of about 0.3 micrometers (μm) or less, and wherein the plated contact layer is a substantially planar layer having a thickness of about 8 micrometers (μm) or less. ### Claim 19 (depends on 16) The device of claim 16, wherein the surface of the conductive seed layer has a surface roughness of more than about 50% of that of the surface on the active layer. ### Claim 20 (depends on 1) The device of claim 1, wherein the surface of the plated contact layer comprises a first surface and wherein: a second surface of the plated contact layer, which is opposite the first surface and is adjacent the protruding features of the light extraction surface on the active layer, conforms to the surface roughness. ### Claim 21 (depends on 2) The device of claim 2, wherein portions of the light extraction surface surrounding the plated contact layer are free of the conductive seed layer. ### Claim 22 A light emitting device, comprising: an active layer configured to provide light emission; a light extraction surface comprising protruding features on the active layer; and an electrically conductive contact structure comprising at least one plated contact layer on the protruding features of the light extraction surface and a conductive seed layer therebetween, wherein a surface of the plated contact layer opposite the light extraction surface is substantial free of a surface roughness by the protruding features of the light extraction surface, and has a greater reflectivity with respect to the light emission than a surface of the conductive seed layer opposite the light extraction surface, and wherein the plated contact layer on the protruding features of the light extraction surface is substantially free of voids therein.