# US 7,745,837 B2 · Semiconductor light-emitting device with high light-extraction efficiency and method 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 7,745,837 B2 - Document ID: US7745837B2 - Status: Granted - Kind: B2 - Application number: 12/000,064 - Filed: 2007-12-07 - Published: 2009-02-19 - Granted: 2010-06-29 - Earliest claimed: 2007-08-15 - Assignees: Huga Optotech Inc. - Inventors: Tzong-Liang Tsai - Web page: https://patentgrep.com/patent/US7745837B2 ## CPC - H10H 20/814: having reflecting means, e.g. semiconductor Bragg reflectors - H10H 20/81: Bodies - H10H 20/82: Roughened surfaces, e.g. at the interface between epitaxial layers - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS ## Abstract The invention discloses a semiconductor light-emitting device and a method of fabricating the same. The semiconductor light-emitting device according to the invention includes a substrate, a first semiconductor material layer, a multi-layer structure and an ohmic electrode structure. The substrate has a first upper surface and a plurality of recesses formed on the first upper surface. The first semiconductor material layer is formed on the first upper surface of the substrate and has a second upper surface. The multi-layer structure is formed on the second upper surface of the first semiconductor material layer and includes a light-emitting region. The ohmic electrode structure is formed on the multi-layer structure. In particular, the first semiconductor material layer has a refractive index different from those of the substrate and a bottom-most layer of the multi-layer structure. ## Claims ### Claim 1 A semiconductor light-emitting device, comprising: an uneven substrate having a first upper surface; a first semiconductor material layer, formed on the first upper surface of the substrate, and the first semiconductor material layer having a second upper surface; a multi-layer structure, formed on the second upper surface of the first semiconductor material layer, and the multi-layer structure comprising a light-emitting region; and an ohmic electrode structure formed on the multi-layer structure; wherein the first semiconductor material layer has a refractive index different from those of the substrate and a bottom-most layer of the multi-layer structure to change a moving direction of a light emitted from the light-emitting region through the first semiconductor material layer. ### Claim 2 (depends on 1) The semiconductor light-emitting device of claim 1, wherein the bottom-most layer of the multi-layer structure is a second semiconductor material layer, and the second semiconductor material layer having a third upper surface, and the refractive index of the second semiconductor material layer being different from those of a bottom-next layer of the multi-layer structure and the first semiconductor material layer. ### Claim 3 (depends on 2) The semiconductor light-emitting device of claim 2, wherein each of the first semiconductor material layer and the second semiconductor material layer is formed of a material selected from the group consisting of a II-V group compound, a II-VI group compound, and a III-V group compound. ### Claim 4 (depends on 3) The semiconductor light-emitting device of claim 3, wherein a II group chemical element in the II-V group compound is one selected from the group consisting of Zn, Be, Mg, Ca, Sr, Ba, and Ra, and a V group chemical element in the II-V group compound is one selected from the group consisting of N, P, and As. ### Claim 5 (depends on 3) The semiconductor light-emitting device of claim 3, wherein a II group chemical element in the II-VI group compound is one selected from the group consisting of Zn, Be, Mg, Ca, Sr, Ba and Ra, and a VI group chemical element in the II-VI group compound is one selected from the group consisting of O, S, Se, Te and Po. ### Claim 6 (depends on 3) The semiconductor light-emitting device of claim 3, wherein a III group chemical element in the III-V group compound is one selected from the group consisting of Al, Ga and In, and a V group chemical element in the III-V group compound is one selected from the group consisting of N, P, and As. ### Claim 7 (depends on 1) The semiconductor light-emitting device of claim 1, wherein the second upper surface of the first semiconductor material layer is rough. ### Claim 8 (depends on 1) The semiconductor light-emitting device of claim 1, wherein the substrate is formed of a material selected from the group consisting of SiO2, Si, Ge, GaN, GaAs, GaP, AIN, sapphire, spinnel, Al2O3, SiC, ZnO, MgO, LiAlO2, LiGaO2, and MgAl2O4. ### Claim 9 A method for fabricating a semiconductor light-emitting device, the method comprising the following steps: preparing an uneven substrate having a first upper surface; forming a first semiconductor material layer on the first upper surface of the substrate, the first semiconductor material layer having a second upper surface; forming a multi-layer structure on the second upper surface of the first semiconductor material layer, the multi-layer structure comprising a light-emitting region; and forming an ohmic electrode structure on the multi-layer structure; wherein the first semiconductor material layer has a refractive index different from those of the substrate and a bottom-most layer of the multi-layer structure to change a moving direction of a light emitted from the light-emitting region through the first semiconductor material layer. ### Claim 10 (depends on 9) The method of claim 9, wherein the bottom-most layer of the multi-layer structure is a second semiconductor material layer, and the second semiconductor material layer having a third upper surface, and the refractive index of the second semiconductor material layer being different from those of a bottom-next layer of the multi-layer structure and the first semiconductor material layer. ### Claim 11 (depends on 10) The method of claim 10, wherein each of the first semiconductor material layer and the second semiconductor material layer is formed of a material selected from the group consisting of a II-V group compound, a II-VI group compound, and a III-V group compound. ### Claim 12 (depends on 11) The method of claim 11, wherein a II group chemical element in the II-V group compound is one selected from the group consisting of Zn, Be, Mg, Ca, Sr, Ba, and Ra, and a V group chemical element in the II-V group compound is one selected from the group consisting of N, P, and As. ### Claim 13 (depends on 11) The method of claim 11, wherein a II group chemical element in the II-VI group compound is one selected from the group consisting of Zn, Be, Mg, Ca, Sr, Ba, and Ra, and a VI group chemical element in the II-VI group compound is one selected from the group consisting of O, S, Se, Te, and Po. ### Claim 14 (depends on 11) The method of claim 11, wherein a III group chemical element in the III-V group compound is one selected from the group consisting of Al, Ga, and In, and a V group chemical element in the III-V group compound is one selected from the group consisting of N, P, and As. ### Claim 15 (depends on 9) The method of claim 9, wherein the second upper surface of the first semiconductor material layer is rough. ### Claim 16 (depends on 9) The method of claim 9, wherein the substrate is formed of a material selected from the group consisting of SiO2, Si, Ge, GaN, GaAs, GaP, AIN, sapphire, spinnel, Al2O3, SiC, ZnO, MgO, LiAlO2, LiGaO2, and MgAl2O4. ### Claim 17 A semiconductor light-emitting device, comprising: an uneven substrate having a first upper surface; a multi-layer structure, formed on the first upper surface of the substrate, and the multi-layer structure comprising a light-emitting region, the multi-layer structure comprising a light-emitting layer, a first semiconductor material layer, and a second semiconductor material layer, the first semiconductor material layer being formed on the light-emitting layer and having a second upper surface, the second semiconductor material layer being formed on the first semiconductor material layer and having a third upper surface; and an ohmic electrode structure formed on the multi-layer structure; wherein the first semiconductor material layer has a refractive index different from those of the light-emitting layer and the second semiconductor material layer to change a moving direction of a light emitted from the light-emitting layer through the first semiconductor material layer. ### Claim 18 (depends on 17) The semiconductor light-emitting device of claim 17, wherein the multi-layer structure further comprises a third semiconductor material layer formed on the third upper surface of the second semiconductor material layer, and the second semiconductor material layer having a refractive index different from those of the first semiconductor material layer and the third semiconductor material layer. ### Claim 19 (depends on 18) The semiconductor light-emitting device of claim 18, wherein each of the first semiconductor material layer, the second semiconductor material layer, and the third semiconductor material layer is formed of a material selected from the group consisting of a II-V group compound, a II-VI group compound, and a III-V group compound. ### Claim 20 (depends on 19) The semiconductor light-emitting device of claim 19, wherein a II group chemical element in the II-V group compound is one selected from the group consisting of Zn, Be, Mg, Ca, Sr, Ba, and Ra, and a V group chemical element in the II-V group compound is one selected from the group consisting of N, P, and As. ### Claim 21 (depends on 19) The semiconductor light-emitting device of claim 19, wherein a II group chemical element in the II-VI group compound is one selected from the group consisting of Zn, Be, Mg, Ca, Sr, Ba and Ra, and a VI group chemical element in the II-VI group compound is one selected from the group consisting of O, S, Se, Te and Po. ### Claim 22 (depends on 19) The semiconductor light-emitting device of claim 19, wherein a III group chemical element in the III-V group compound is one selected from the group consisting of Al, Ga and In, and a V group chemical element in the III-V group compound is one selected from the group consisting of N, P, and As. ### Claim 23 (depends on 17) The semiconductor light-emitting device of claim 17, wherein the second upper surface of the first semiconductor material layer is rough. ### Claim 24 (depends on 17) The semiconductor light-emitting device of claim 17, wherein the substrate is formed of a material selected from the group consisting of SiO2, Si, Ge, GaN, GaAs, GaP, AIN, sapphire, spinnel, Al2O3, SiC, ZnO, MgO, LiAlO2, LiGaO2, and MgAl2O4.