# US 10,319,881 B2 · Device including transparent layer with profiled surface for improved extraction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,319,881 B2 - Document ID: US10319881B2 - Status: Granted - Kind: B2 - Application number: 15/390,575 - Filed: 2016-12-26 - Published: 2017-04-13 - Granted: 2019-06-11 - Earliest claimed: 2011-06-15 - Assignees: Sensor Electronic Technology, Inc. - Applicants: Sensor Electronic Technology, Inc. - Inventors: Maxim S. Shatalov; Alexander Dobrinsky; Michael Shur; Remigijus Gaska - Web page: https://patentgrep.com/patent/US10319881B2 ## CPC - H10H 20/82: Roughened surfaces, e.g. at the interface between epitaxial layers - G06F 30/20: Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) - G06F 30/30: Circuit design - H10H 20/01335: {the light-emitting regions comprising nitride materials} - H10H 20/819: characterised by their shape, e.g. curved or truncated substrates - H10H 20/825: containing nitrogen, e.g. GaN - H10H 20/857: Interconnections, e.g. lead-frames, bond wires or solder balls - H10H 20/814: having reflecting means, e.g. semiconductor Bragg reflectors - H10H 20/872: {Periodic patterns for optical field-shaping, e.g. photonic bandgap structures} - Y10T 29/49: Method of mechanical manufacture - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A profiled surface for improving the propagation of radiation through an interface is provided. The profiled surface includes a set of large roughness components providing a first variation of the profiled surface having a characteristic scale approximately an order of magnitude larger than a target wavelength of the radiation. The set of large roughness components can include a series of truncated shapes. The profiled surface also includes a set of small roughness components superimposed on the set of large roughness components and providing a second variation of the profiled surface having a characteristic scale on the order of the target wavelength of the radiation. ## Claims ### Claim 1 A device comprising: a group III nitride heterostructure; and an at least partially transparent substrate having a first side and a second side, wherein the group III nitride heterostructure is located on the second side, and wherein radiation passes through the second side, and wherein the second side comprises a profiled surface, the profiled surface including: a plurality of large roughness components providing a first variation of the profiled surface having a characteristic scale approximately an order of magnitude larger than a target wavelength of the radiation, wherein the plurality of large roughness components comprise a series of truncated shapes formed of a material of the at least partially transparent substrate, wherein at least one of the series of truncated shapes is inversely truncated with respect to a direction the radiation travels through the at least partially transparent substrate; and a plurality of small roughness components providing a second variation of the profiled surface having a characteristic scale on the order of the target wavelength of the radiation, wherein the plurality of small roughness components are superimposed on the plurality of large roughness components, wherein a graded refractive index along a height of each small roughness component in the plurality of small roughness components decreases substantially linearly along the height. ### Claim 2 (depends on 1) The device of claim 1, wherein a size of each of the plurality of large roughness components varies laterally across the profiled surface. ### Claim 3 (depends on 2) The device of claim 2, wherein the variation in size between each of the large roughness components in the plurality of large roughness components is radially monotonic. ### Claim 4 (depends on 1) The device of claim 1, wherein a height of each of the plurality of large roughness components varies laterally across the profiled surface. ### Claim 5 (depends on 1) The device of claim 1, wherein a third side of the at least partially transparent substrate includes the profiled surface. ### Claim 6 (depends on 1) The device of claim 1, wherein the profiled surface further comprises a set of layers deposited in a region between each of the plurality of large roughness components. ### Claim 7 (depends on 6) The device of claim 6, wherein the set of layers are formed of a material that is partially transparent to the target wavelength and has an index of refraction that is different than an index of refraction of a material of the at least partially transparent substrate. ### Claim 8 (depends on 1) The device of claim 1, wherein the target wavelength of the radiation is between 250 nanometers and 350 nanometers. ### Claim 9 A method comprising: designing a profiled surface for an at least partially transparent substrate of a device, wherein the at least partially transparent substrate includes a first side and a second side, wherein a group Ill nitride heterostructure is located on the second side, and wherein radiation passes through the second side during operation of the device, wherein the profiled surface includes: a plurality of large roughness components providing a first variation of the profiled surface having a characteristic scale approximately an order of magnitude larger than a target wavelength of the radiation, wherein the plurality of large roughness components comprise a series of truncated shapes formed of a material of the at least partially transparent substrate, wherein at least one of the series of truncated shapes is inversely truncated with respect to a direction the radiation travels through the at least partially transparent substrate; and a plurality of small roughness components providing a second variation of the profiled surface having a characteristic scale on the order of the target wavelength of the radiation, wherein the plurality of small roughness components are superimposed on the plurality of large roughness components, wherein a graded refractive index along a height of each small roughness component in the plurality of small roughness components decreases substantially linearly along the height. ### Claim 10 (depends on 9) The method of claim 9, further comprising fabricating the device including the at least partially transparent substrate, wherein the fabricating includes fabricating the profiled surface. ### Claim 11 (depends on 10) The method of claim 10, wherein the fabricating the profiled surface includes forming at least one of: the set of large roughness components or the set of small roughness components using at least one of: selective deposition or selective etching of nanodots. ### Claim 12 (depends on 10) The method of claim 10, wherein the fabricating the profiled surface includes forming at least one of: the set of large roughness components or the set of small roughness components using at least one of: selective deposition or selective etching of nanorods. ### Claim 13 (depends on 10) The method of claim 10, wherein fabricating the profiled surface includes performing a simulation using ray tracing and a genetic algorithm. ### Claim 14 An emitting device comprising: an active region configured to generate radiation having a peak wavelength; and an at least partially transparent substrate having a first side and a second side, wherein the active region is located on the first side, wherein radiation generated in the active region passes through the second side, and wherein the at least partially transparent substrate includes a profiled surface, wherein the profiled surface includes: a plurality of large roughness components providing a first variation of the profiled surface having a characteristic scale approximately an order of magnitude larger than a target wavelength of the radiation, wherein the plurality of large roughness components comprise a series of truncated shapes formed of a material of the at least partially transparent substrate, wherein at least one of the series of truncated shapes is inversely truncated with respect to a direction the radiation travels through the at least partially transparent substrate; and a plurality of small roughness components providing a second variation of the profiled surface having a characteristic scale on the order of the target wavelength of the radiation, wherein the plurality of small roughness components are superimposed on the plurality of large roughness components, wherein a graded refractive index along a height of each small roughness component in the plurality of small roughness components decreases substantially linearly along the height. ### Claim 15 (depends on 14) The device of claim 14, wherein a size of each of the plurality of large roughness components varies laterally across the profiled surface. ### Claim 16 (depends on 15) The device of claim 15, wherein the variation in size between each of the large roughness components in the plurality of large roughness components is radially monotonic. ### Claim 17 (depends on 14) The device of claim 14, wherein a height of each of the plurality of large roughness components varies laterally across the profiled surface. ### Claim 18 (depends on 14) The device of claim 14, wherein a third side of the at least partially transparent substrate includes the profiled surface. ### Claim 19 (depends on 14) The device of claim 14, wherein the profiled surface further comprises a set of layers deposited in a region between each of the plurality of large roughness components. ### Claim 20 (depends on 14) The device of claim 14, wherein the target wavelength of the radiation is between 250 nanometers and 350 nanometers.