# US 2021/0242086 A1 · Method of removing semiconducting layers from a semiconducting substrate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0242086 A1 - Document ID: US20210242086A1 - Status: Published application - Kind: A1 - Application number: 17/049,156 - Filed: 2019-05-30 - Published: 2021-08-05 - Earliest claimed: 2018-05-30 - Assignees: The Regents of the University of California - Applicants: The Regents of the University of California - Inventors: Srinivas Gandrothula; Takeshi Kamikawa - Web page: https://patentgrep.com/patent/US20210242086A1 ## CPC - H10D 86/0214: {using temporary substrates} - H10P 95/112: {leaving a reusable substrate, e.g. epitaxial lift off} - C30B 25/04: Pattern deposit, e.g. by using masks - C30B 25/20: the substrate being of the same materials as the epitaxial layer - C30B 29/403: {AIII-nitrides} - C30B 33/02: Heat treatment (C30B33/04, C30B33/06 take precedence) - H10D 86/451: {characterised by the compositions or shapes of the interlayer dielectrics} - H10D 86/60: wherein the TFTs are in active matrices - H10H 20/013: {having light-emitting regions comprising only Group III-V materials} - H10H 20/815: having stress relaxation structures, e.g. buffer layers - H10H 20/819: characterised by their shape, e.g. curved or truncated substrates - H10P 14/271: {characterised by the preparation of substrate for selective deposition} - H10P 14/276: {Lateral overgrowth} - H10P 14/2908: {Nitrides} - H10P 14/3216: {Nitrides} - H10P 14/3416: {Nitrides} - H10P 95/11: {Separation of active layers from substrates} - H01S 5/04252: {characterised by the material} - H01S 5/2214: {based on oxides or nitrides} - H01S 5/34333: {with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser} - H01S 2304/04: MOCVD or MOVPE - H10P 14/24: using chemical vapour deposition [CVD] - H10P 14/272: {using mask materials other than SiO2 or SiN} - H10P 14/2926: {Crystal orientations} - H10P 14/3444: {P-type} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL ## Abstract A method of removing semiconducting layers from a substrate, in particular, III-nitride-based semiconductor layers from a III-nitride-based substrate, with an attached film, using a peeling technique. The method comprises forming the semiconductor layers into island-like patterns on the substrate via an epitaxial lateral overgrowth method, with a horizontal trench extending inwards from the sides of the layers. Stress is induced in the layers by raising or lowering the temperature, and applying pressure to the attached film, such that the film firmly fits a shape of the layers. Differences in thermal expansion between the substrate and the film attached to the layers initiates a crack at an interface between the layers and the substrate, so that the layers can be removed from the substrate. Once the layers are removed, the substrate can be recycled, resulting in cost savings for device fabrication. ## Claims ### Claim 1 A method of removing semiconductor layers from a substrate, comprising: forming one or more island-like semiconductor layers on a substrate; applying a film to the island-like semiconductor layers; applying a pressure on the film from one or more sides; changing a temperature of the film and the substrate; and peeling the film with the island-like semiconductor layers from the substrate, after the pressure is applied and the temperature is changed. ### Claim 2 (depends on 1) The method of claim 1, wherein the film comprises a polymer or polymer/adhesive film. ### Claim 3 (depends on 1) The method of claim 1, wherein the film has a top layer and a bottom layer, and the bottom layer is pushed inwards to a recess region between the island-like semiconductor layers. ### Claim 4 (depends on 3) The method of claim 3, the top layer is harder than the bottom layer. ### Claim 5 (depends on 1) The method of claim 1, wherein a bottom surface of the film on or above the island-like semiconductor layers is pushed to a level at least below a top surface of the island-like semiconductor layers. ### Claim 6 (depends on 5) The method of claim 5, wherein the bottom surface of the film reaches below a surface of a convexity region of the island-like semiconductor layers. ### Claim 7 (depends on 1) The method of claim 1, wherein the film is applied below a top surface of the island-like semiconductor layers and on to a surface of the substrate. ### Claim 8 (depends on 1) The method of claim 1, wherein a compressible material is placed upon the film to improve its attachment to the island-like semiconductor layers; and the pressure is applied to the compressible material for improved bonding of the film to the island-like semiconductor layers. ### Claim 9 (depends on 1) The method of claim 1, the temperature is changed to lower the temperature of the film and the substrate. ### Claim 10 (depends on 1) The method of claim 1, wherein a thermal expansion coefficient of the film is different from the island-like semiconductor layers and the substrate. ### Claim 11 (depends on 1) The method of claim 1, wherein the pressure is removed before the temperature is changed. ### Claim 12 (depends on 1) The method of claim 1, wherein the island-like semiconductor layers are III-nitride-based semiconductor layers. ### Claim 13 (depends on 1) The method of claim 1, wherein the substrate is a III-nitride-based substrate or a foreign or hetero-substrate. ### Claim 14 (depends on 1) The method of claim 1, wherein one or more of the steps of applying the film to the island-like semiconductor layers; applying the pressure on the film; changing the temperature of the film and the substrate; and peeling the film with the island-like semiconductor layers from the substrate; is performed by an automated apparatus. ### Claim 15 (depends on 1) The method of claim 1, wherein the island-like semiconductor layers are randomly shaped. ### Claim 16 (depends on 1) The method of claim 1, wherein the film with the island-like semiconductor layers is peeled from the substrate in any direction. ### Claim 17 (depends on 1) The method of claim 1, wherein one or more of the steps of applying the film to the island-like semiconductor layers; applying the pressure on the film; changing the temperature of the film and the substrate; and peeling the film with the island-like semiconductor layers from the substrate; are repeated to remove the island-like semiconductor layers from the substrate. ### Claim 18 (depends on 1) The method of claim 1, wherein the island-like semiconductor layers are patterned with a horizontal trench extended inwards to a center of the island-like semiconductor layers with at least one side vertically below the island-like semiconductor layers. ### Claim 19 (depends on 1) The method of claim 1, wherein cracks are induced into the island-like semiconductor layers at or above an interface between the island-like semiconductor layers and the substrate. ### Claim 20 (depends on 1) The method of claim 1, wherein at least a portion of the island-like semiconductor layers remains with the substrate after the peeling. ### Claim 21 (depends on 1) The method of claim 1, wherein no portion of the substrate remains with the island-like semiconductor layers after the peeling. ### Claim 22 (depends on 1) The method of claim 1, wherein the island-like semiconductor layers are formed on the substrate using a growth restrict mask and epitaxial lateral overgrowth, and the epitaxial lateral overgrowth is stopped before the island-like semiconductor layers coalesce. ### Claim 23 (depends on 1) A device fabricated by the method of claim 1.