# US 12,119,425 B2 · Multi-junction light-emitting diode and method for making the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,119,425 B2 - Document ID: US12119425B2 - Status: Granted - Kind: B2 - Application number: 17/655,097 - Filed: 2022-03-16 - Published: 2022-06-30 - Granted: 2024-10-15 - Earliest claimed: 2020-02-19 - Assignees: Tianjin Sanan Optoelectronics Co., Ltd. - Applicants: Tianjin Sanan Optoelectronics Co., Ltd. - Inventors: Chihhung Hsiao; Yu-Ren Peng; Kunhuang Cai; Duxiang Wang; Chia-Hung Chang - Web page: https://patentgrep.com/patent/US12119425B2 ## CPC - H10H 20/813: having a plurality of light-emitting regions, e.g. multi-junction LEDs or light-emitting devices having photoluminescent regions within the bodies - H10H 20/0137: {the light-emitting regions comprising nitride materials} - H10H 20/812: within the light-emitting regions, e.g. having quantum confinement structures - H10H 20/8215: {characterised by crystalline imperfections, e.g. dislocations; characterised by the distribution of dopants, e.g. delta-doping} - H10H 20/824: comprising only Group III-V materials, e.g. GaP - H10H 20/8242: {characterised by the dopants} - H10H 20/018: {Bonding of wafers} - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS ## Abstract A multi-junction light-emitting diode (LED) includes a first epitaxial structure, a second epitaxial structure and a tunnel junction structure disposed therebetween. The tunnel junction structure includes a InzAlX1Ga1−X1As highly doped p-type semiconductor layer wherein z ranges from 0 to 0.05, a AlX2Ga1−X2As first composition graded layer wherein X2 is greater than 0 and less than X1, a GaYIn1−YP highly doped n-type semiconductor layer and a AlX3Ga1−X3As second composition graded layer that are sequentially disposed on the first epitaxial structure in such order. A method for making the abovementioned multi-junction LED is also disclosed. ## Claims ### Claim 1 A multi-junction light-emitting diode (LED), comprising a first epitaxial structure, a second epitaxial structure, and a tunnel junction structure disposed between said first epitaxial structure and said second epitaxial structure, said tunnel junction structure including: a highly doped p-type semiconductor layer that is made of a material represented by InzAlX1Ga1−X1As, z ranging from 0 to 0.05; a first composition graded layer that is disposed on said highly doped p-type semiconductor layer and that is made of a material represented by AlX2Ga1−X2As, X2 being greater than 0 and less than X1; a highly doped n-type semiconductor layer that is disposed on said first composition graded layer opposite to said highly doped p-type semiconductor layer and that is made of a material represented by GaYIn1−YP; and a second composition graded layer that is disposed on said highly doped n-type semiconductor layer opposite to said first composition graded layer and that is made of a material represented by AlX3Ga1−X3As. ### Claim 2 (depends on 1) The multi-junction LED of claim 1, wherein in said highly doped p-type semiconductor layer, X1 is greater than 0 and not greater than 0.8. ### Claim 3 (depends on 1) The multi-junction LED of claim 1, wherein said highly doped p-type semiconductor layer has a doping concentration not less than 1×1019 cm−3. ### Claim 4 (depends on 1) The multi-junction LED of claim 1, wherein said highly doped p-type semiconductor layer is doped with carbon at a doping concentration ranging from 1×1019 cm−3 to 2×1020 cm−3. ### Claim 5 (depends on 1) The multi-junction LED of claim 1, wherein said highly doped p-type semiconductor layer has a thickness ranging from 10 nm to 100 nm. ### Claim 6 (depends on 1) The multi-junction LED of claim 1, wherein in said highly doped n-type semiconductor layer, Y ranges from 0.45 to 0.7. ### Claim 7 (depends on 1) The multi-junction LED of claim 1, wherein said highly doped n-type semiconductor layer has a doping concentration not less than 1×1019 cm−3. ### Claim 8 (depends on 1) The multi-junction LED of claim 1, wherein said highly doped n-type semiconductor layer is doped with tellurium at a doping concentration ranging from 1×1019 cm−3 to 2×1020 cm−3. ### Claim 9 (depends on 8) The multi-junction LED of claim 8, wherein said highly doped n-type semiconductor layer is further doped with silicon at a doping concentration ranging from 5×1018 cm−3 to 2×1019 cm−3. ### Claim 10 (depends on 9) The multi-junction LED of claim 9, wherein in said highly doped n-type semiconductor layer, the doping concentration of tellurium to the doping concentration of silicon is in a ratio ranging from 5:3 to 2:1. ### Claim 11 (depends on 1) The multi-junction LED of claim 1, wherein said highly doped n-type semiconductor layer has a thickness ranging from 10 nm to 100 nm. ### Claim 12 (depends on 1) The multi-junction LED of claim 1, wherein in said first composition graded layer, X2 gradually decreases in a direction from said highly doped p-type semiconductor layer toward said highly doped n-type semiconductor layer. ### Claim 13 (depends on 12) The multi-junction LED of claim 12, wherein X2 linearly decreases in a direction from said highly doped p-type semiconductor layer toward said highly doped n-type semiconductor layer. ### Claim 14 (depends on 1) The multi-junction LED of claim 1, wherein said first composition graded layer is a p-type semiconductor layer which is doped with carbon at a doping concentration ranging from 1×1019 cm−3 to 5×1019 cm−3. ### Claim 15 (depends on 1) The multi-junction LED of claim 1, wherein said first composition graded layer has a thickness ranging from 10 nm to 50 nm. ### Claim 16 (depends on 1) The multi-junction LED of claim 1, wherein in said second composition graded layer, X3 gradually increases in a direction away from said highly doped n-type semiconductor layer. ### Claim 17 (depends on 16) The multi-junction LED of claim 16, wherein X3 linearly increases in a direction away from said highly doped n-type semiconductor layer. ### Claim 18 (depends on 1) The multi-junction LED of claim 1, wherein said second composition graded layer is an n-type semiconductor layer which is doped with tellurium at a doping concentration ranging from 1×1019 cm−3 to 5×1019 cm−3. ### Claim 19 (depends on 1) The multi-junction LED of claim 1, wherein said second composition graded layer has a thickness ranging from 10 nm to 50 nm. ### Claim 20 (depends on 1) The multi-junction LED of claim 1, wherein each of said first and second epitaxial structures independently emits an infrared light having a wavelength ranging from 760 nm to 1100 nm. ### Claim 21 A method for making a multi-junction LED, comprising the steps of: (A) forming a first epitaxial structure, (B) forming a tunnel junction structure on the first epitaxial structure, wherein the tunnel junction structure includes: a highly doped p-type semiconductor layer that is made of a material represented by InzAlX1Ga1−X1As, z ranging from 0 to 0.05; a first composition graded layer that is disposed on the highly doped p-type semiconductor layer and that is made of a material represented by AlX2Ga1−X2As, X2 being greater than 0 and less than X1; a highly doped n-type semiconductor layer that is disposed on the first composition graded layer opposite to the highly doped p-type semiconductor layer and that is made of a material represented by GaYIn1−YP; and a second composition graded layer that is disposed on the highly doped n-type semiconductor layer opposite to the first composition graded layer and that is made of a material represented by AlX3Ga1−X3As, and (C) forming a second epitaxial structure on the tunnel junction structure opposite to the first epitaxial structure.