SUPPORT PROVIDED WITH A LAYER OF GRAPHENE OXIDE, INTENDED FOR THE TRANSFER OF A LAYER BY LASER SEPARATION, AND MANUFACTURING METHOD

Abstract

Starting structure (Struct_0) designed to undergo separation by laser irradiation, comprising a substrate (Sub2), a transferred layer (TrLay), and a graphene oxide layer (GO, GO2) interposed between the substrate (Sub2) and the transferred layer (TrLay). Figure to be published with the abstract: Fig. 1

Description

Title of the invention: SUPPORT PROVIDED WITH A LAYER OF GRAPHENE OXIDE, INTENDED FOR THE TRANSFER OF A LAYER BY LASER SEPARATION, AND MANUFACTURING METHOD TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a support provided with one or more layers to be transferred and intended to be separated from at least part of the support by laser irradiation at a separation layer included in the support, with a view to manufacturing products in the field of semiconductors. TECHNOLOGICAL BACKGROUND

[0002] The semiconductor industry is increasingly employing thin film transfer techniques, which consist, in a first step, of forming a thin film on a first substrate, then, in a second step, of transferring the formed thin film onto a second substrate.

[0003] The first substrate may be chosen for its compatibility with the conditions for forming the thin layer, or the thin layer may be formed in the mass of the material forming this first substrate.

[0004] The second substrate is suitable for the exploitation of this thin layer, for example by being compatible with subsequent manufacturing steps or even by carrying a structure on which the thin layer will be integrated.

[0005] Among the thin film transfer techniques used in the semiconductor industry, laser separation (laser lift-off or LLO according to the generally used English terminology) has emerged as an effective method for separating a film or a stack of several films or one or more thin layers from a carrier substrate using a layer, called a separation layer, the separation or degradation of which is triggered by a laser.

[0006] In general, the separation layer is irradiated by laser through the carrier substrate. The separation layer must absorb a sufficient amount of light at the laser wavelength to promote separation or its degradation (e.g., by locally melting the separation layer or causing it to dissociate into its elementary component), while the carrier substrate must be essentially transparent at this wavelength. A balance between laser power, laser wavelength, and material selection (for the separation layer and the carrier substrate) must be found to enable separation while preserving the layer(s) to be transferred from the impact of energy dissipation due to light interaction process: heat transfer due to absorption in the separation layer or direct absorption of part of the laser irradiation by the layer or layers to be transferred.

[0007] US Patent 11,069,865 B2 describes a method for manufacturing a flexible OLED display panel, in which the display panel is manufactured on a glass plate covered with an organic separating layer that strongly absorbs UV radiation. The display panel is detached from the glass plate by a laser separation operation, in which the separating layer, capable of absorbing ultraviolet radiation, is irradiated through the glass plate by a laser operating in the ultraviolet range, facilitating the separation.

[0008] The number of candidate materials acting as a separation layer is limited and even rarer if we consider the contamination specifications in semiconductor device production processes, in particular during so-called "front-end" operations in English terminology. One of the most used materials is gallium nitride GaN, which constitutes an interesting solution for LLO by irradiation in the UV ultraviolet (designated as UV-LLO), as described in US patent 8,598,014 B2.

[0009] However, the use of GaN in production lines is often associated with contamination in the "front-end" and "back-end" lines. In addition, UV-LLO associated with GaN requires thick layers of GaN, part of which is burned by the laser to perform LLO and a remaining part is affected by the high temperature caused by laser irradiation. Using UV for LLO is also time-consuming because it requires a complex laser setup and presents energy-related risks for both samples and operators. Statement of the invention

[0010] An object of the invention is the use of a graphene oxide layer as an optically absorbing layer in a method of layer separation by LLO laser irradiation, solving the problems mentioned above. More specifically, the invention relates to a structure capable of undergoing separation by laser irradiation as well as a method for manufacturing this structure.

[0011] Another object of the invention is a method of manufacturing an advanced structure based on the structure obtained by the method of the first object of the invention.

[0012] With a view to achieving these objects, a first aspect of the invention is a starting structure designed to undergo separation by laser irradiation, comprising a substrate, a transferred layer, and a graphene oxide layer interposed between the substrate and the transferred layer.

[0013] The structure according to the invention makes it possible to provide a structure ready to be integrated into a method of manufacturing a semiconductor device requiring the transfer of a layer from a first support to a second support. We can thus speak of a starting structure or substrate of an integrated method of manufacturing a semiconductor device substrate called "Epi-Ready" in English terminology, for the reason that this structure or this substrate is ready to serve as a support for the growth of a layer by epitaxy. More generally, this layer is capable of being subjected to any manufacturing step conventionally used in the field of the semiconductor industry, such as a photolithography step, thermal or plasma treatment, or even deposition of layers of electrically conductive, insulating or semiconducting materials.

[0014] An advantage of the structure according to the invention is to provide an alternative to existing solutions, which can lead to troublesome contamination of the devices to be manufactured from this structure.

[0015] Another advantage is the optical absorption rate of infrared radiation by the graphene oxide layer. During the laser irradiation separation operation, the energy of the incident radiation will be essentially absorbed by the graphene layer if the radiation has a suitable wavelength, limiting the thermal degradation of the rest of the structure, and in particular of the layer that is transferred to the second support.

[0016] An additional advantage is the resistance of the graphene oxide layer to high temperatures, typical, for example, of epitaxial layer deposition processes which are usually carried out between 800 and 1500°C. For this additional reason, the structure according to the invention is compatible with a large number of processes which can be applied to it in the field of semiconductors.

[0017] According to additional non-limiting characteristics of the first aspect of the invention, considered individually or in any technically feasible combination: - the substrate may be transparent to infrared radiation; - the substrate may be transparent to radiation of wavelength between 9 and 11 pm; - the substrate may be made of silicon Si or silicon carbide SiC; and - the transferred layer can be made of mono silicon carbide SiC crystalline or sapphire.

[0018] A second aspect of the invention is a method for manufacturing the starting structure of the first subject of the invention, comprising: a step of providing two substrates; a step of forming at least one layer of multilayer graphene on at least one of the two substrates; a step of oxygenating the at least one layer of multilayer graphene so as to form at least one layer of oxide of graphene; a step of assembling the two substrates via at least one layer of graphene oxide; and a step of detaching a portion of one of the two substrates so as to leave the transferred layer on the other of the two substrates.

[0019] According to additional non-limiting characteristics of the second aspect of the invention, considered individually or in any technically feasible combination:

[0020] - the assembly step can be carried out by direct contact;

[0021] - a multi-layer graphene layer can be formed on each of the two substrates; and

[0022] - the method may further comprise a step of ion implantation in the first substrate, so as to form a weakening plane in this first substrate and thus define the transferred layer.

[0023] A third aspect of the invention is a method of manufacturing an advanced structure comprising a layer formed by epitaxy on the transferred layer of the structure according to claim 1, the method comprising the steps of: providing the starting structure according to the first aspect of the invention; forming by epitaxy the layer formed by epitaxy on the transferred layer of the provided structure; assembling a third substrate to the structure by bringing this third substrate into direct contact with the epitaxial layer; and irradiating the graphene oxide layer with infrared irradiation, so as to separate the transferred layer, the epitaxial layer and the third substrate from the substrate of the starting structure.

[0024] According to additional non-limiting characteristics of the third aspect of the invention, considered individually or in any technically feasible combination:

[0025] - the irradiation uses an electromagnetic wave of wavelength between between 9 and 11 pm;

[0026] - the method may further comprise a step of releasing the following layer the separation step; and

[0027] - the epitaxial layer is a layer of gallium nitride GaN.

[0028] An advantage of the methods is their simplicity and excellent technical benefit in relation to their cost.

[0029] Another advantage of the methods according to the invention arises from the simplicity of using laser irradiation in the infrared range coupled with the use of materials compatible with semiconductor device manufacturing methods. BRIEF DESCRIPTION OF THE FIGURES

[0030] Other characteristics and advantages of the invention will emerge from the detailed description of the invention which follows with reference to the appended figures in which:

[0031] [Fig.l] [Fig.l] illustrates the steps of a method of manufacturing a starting structure according to the invention;

[0032] [Fig.2] [Fig.2] is a diagram summarizing the steps of the manufacturing process of [Fig.l];

[0033] [Fig.3] [Fig.3] illustrates a variant of the method of figures 1 and 2;

[0034] [Fig.4] [Fig.4] illustrates a method of manufacturing an advanced structure on the base of the starting structure of [Fig.l];

[0035] [Fig.5] [Fig.5] is a diagram summarizing the steps of the manufacturing process of [Fig.4]; and

[0036] [Fig.6] [Fig.6] illustrates one of the steps of the method of Figures 4 and 5. DETAILED DESCRIPTION OF THE INVENTION

[0037] Embodiment of the invention - Structure Struct_0

[0038] One embodiment of the invention is detailed below and illustrated by Figures 1 to 3.

[0039] [Fig.l] illustrates the steps of a method 100 for manufacturing a first structure Struct_0 according to the invention. One aim of this manufacturing method is to obtain a structure capable of serving as a basis for developing a device in the field of the semiconductor industry. Specifically, the structure Struct_0 comprises a TrLay layer supported by a substrate Sub2 via a graphene oxide layer GO, the latter being able to be degraded and / or reduced by infrared laser irradiation so as to detach the TrLay layer from the substrate Sub2. The advantage of this operation will be explained by example using FIGS. 4 to 6.

[0040] The method 100 begins by providing two substrates Subi and Sub2 at two providing steps 110 and 120, respectively. In this exemplary implementation of the invention, the substrates Subi and Sub2 are made of planar silicon carbide substrates, such as silicon carbide SiC wafers.

[0041] In steps 130 and 140, multilayer graphene layers MG1 and MG2, made of carbon atoms C, are formed on the surface of the SiC substrates Subi and Sub2 by a conventional heat treatment, preferentially sublimating the silicon atoms Si of the SiC surfaces. The number of graphene layers can be between 5 and 20, which corresponds to thicknesses between 1.5 and 14 nm. Reference may be made, for example, to the article by Piort Ciochon et al., “Reversible graphitization of SiC: A route towards high-quality graphene on a minimally step bunched substrate”, in Applied Surface Science 528 (2020) 146917. To promote obtaining the graphene layers MG1 and MG2 by this step, the SiC substrates are preferably formed from monocrystalline SiC.

[0042] Alternatively, the graphene layers can be obtained by CVD, Chemical Vapor Deposition in English terminology. In this case, SiC substrates can be polycrystalline as well as monocrystalline.

[0043] At a step 150 of implantation of at least one light species, the Subi substrate is prepared at a step of separation of the TrLay layer from a part of the thickness of the Subi substrate, for example according to Smart Cut™ technology.

[0044] For this purpose, the substrate Subi must be prepared by introducing at least one light species such as hydrogen or helium into this substrate. This introduction may correspond to a hydrogen implantation, that is to say, an ion bombardment of hydrogen, here through the graphene layer MG1. In a manner known per se, and as illustrated by [Fig.l], the hydrogen ions H+ are implanted so as to form a weakening plane Frgl delimiting the layer TrLay to be transferred. The layer TrLay is located on the side of the graphene layer MG1 with respect to this weakening plane Frgl.

[0045] The nature, the dose of the implanted species and the implantation energy are chosen according to the thickness of the layer that one wishes to transfer and the physicochemical properties of the Subi substrate. In the case of a Subi substrate in SiC, one can choose to implant a dose of hydrogen between 1016 and 5.1017 at / cm2 with an energy between 30 and 300 keV to delimit a TrLay layer of the order of 200 to 2000 nm thick.

[0046] At oxygenation steps 160 and 170, the graphene layers MG1 and MG2 are oxygenated to form graphene oxide layers OG1 and OG2, respectively. These operations can be carried out, for example, according to the Hummers method or one of its derivatives, which involve treating the graphene layers with KMnO4 and NaO3 in concentrated sulfuric acid H2SO4. Reference may be made to the article by Daniela C. Marcanao et al., “Improved synthesis of graphene oxide,” in ACS Nano 2010, 4, 8, 4806-4814.

[0047] There are two reasons for carrying out these oxygenation steps.

[0048] The first reason is that the oxygenation of the graphene layer adds functional groups (carbonyl, hydroxyl, epoxy) to it which give it greater hydrophilicity, which facilitates the bonding of these two layers to each other in the following step 200.

[0049] The second reason is that the C-O chemical bonds between the carbon atoms and the oxygen atoms strongly absorb infrared radiation of about 1087 cm 1 wavelength. This characteristic will be used to advantage in step 340 of the method 300 illustrated by Figures 4 to 6.

[0050] In an assembly step 200, the two substrates Subi and Sub2 are assembled to each other by placing the graphene oxide layer GO1 in direct contact with the graphene oxide layer GO2. These two layers adhere to each other by molecular bonding. In this way, a stack Stck is formed comprising, in this order, the substrate Sub2, the layer GO2, the layer GO1, and the substrate Subi. The substrate Subi comprises the weakening plane Frgl. The layers GO1 and GO2 can be considered collectively to form a layer of graphene oxide GO.

[0051] At a detachment step S210 following step 200, the substrate Subi is cleaved into two parts at the weakening plane Frgl, in this example according to the Smart Cut™ process.

[0052] Thus, in the present embodiment, a portion of the substrate Subi is detached from the rest of its volume to form a layer of interest, here the TrLay layer. As explained above, this layer was defined by the volume of the substrate Subi located between the weakening plane Frgl and the graphene layer MG1, now the graphene oxide layer GO1. After the assembly step between the substrates Subi and Sub2, this TrLay layer is detached from the rest of the substrate Subi by fracture at the weakening plane Frgl and is thus transferred to the support Sub2. The assembly obtained is designated by Structuct_O, a structure comprising, in this order, the substrate Sub2, the layer GO2, the layer GO1, and the TrLay layer, which was transferred from the substrate Subi to the substrate Sub2.

[0053] This detachment step can thus comprise the application to the stack Stck of a heat treatment in a temperature range of the order of 80°C to 500°C to allow the detachment of the layer TrLay and thus complete the transfer of the latter onto the substrate Sub2. As a replacement or in addition to the heat treatment, this step can comprise the application of a blade or a jet of gaseous or liquid fluid, or any other force of a mechanical nature at the level of the embrittlement plane Frgl.

[0054] In an optional step 220 following the detachment step 210 which led to obtaining the Stck stack, a stabilization heat treatment can be applied to the Stck stack. The stabilization heat treatment makes it possible to cure crystalline defects present in the TrLay layer. This heat treatment can be provided to bring the stack to a temperature of between 300°C and 600°C for a duration of between 30 minutes and 10 hours. This heat treatment is preferably carried out by exposing the free face of the dielectric layer to a neutral gas atmosphere.

[0055] Following the detachment of the TrLay layer from the rest of the Subi substrate, its free surface is irregular. In order to put it in a condition to serve as a support for, for example, a step of growth of a layer by epitaxy, a transfer to a third substrate, or any other operation such as those conventionally used in the semiconductor industry, it is necessary to prepare this surface and in particular to reduce its roughness, ideally so as to make it atomically flat.

[0056] Thus, at a surface preparation step 230, which may precede or follow step 220, a planarization and polishing treatment is applied to the TrLay layer. This may be a chemical mechanical polishing treatment, often designated by the acronym CMP for Chemical Mechanical Polishing in English terminology.

[0057] Following the surface treatment step 230 and, where appropriate, the stabilization step 220, the structure Struct_0 can be considered as capable of serving, for example, as a support for the formation of a layer by epitaxy.

[0058] [Fig. 3] illustrates a variant of the method 100. In this variant, a single graphene layer is formed and then oxidized. It is preferable to keep the graphene layer which will not be crossed by ions during the formation of the weakening plane Frgl. More specifically, the method 100 remains the same, except that the graphene multilayer MG1 is not formed, and is therefore not oxidized. Thus, during the assembly step 200, the graphene oxide layer GO2 is brought into direct contact with the substrate Subi. This layer is therefore formed directly on the volume of material of the substrate Subi intended to form the layer TrLay. In the stack Stck, the layer TrLay is defined by the volume of the substrate Subi located between the weakening plane Frgl and the graphene layer GO2. The graphene layer GO is here formed solely from the graphene layer GO2.

[0059] The thicknesses of the graphene layers GO2 and, where appropriate, GO1, can be adapted to define the thickness of the GO layer in order to absorb a greater or lesser portion of incident infrared radiation during a subsequent laser separation step. These thicknesses will be determined, according to the operator's criteria, depending on the nature of the layers to be separated.

[0060] Embodiment of the invention - Structure Struct_l

[0061] Figures 4 to 6 illustrate an example of a process using the Struct_0 structure, with the formation of an epitaxial layer Epi directly on the TrLay layer, and the transfer of this epitaxial layer onto a Sub3 support.

[0062] This example illustrates the obtaining of an advanced structure Struct_l comprising a support Sub3 supporting an epitaxial layer of gallium nitride GaN.

[0063] A method 300 according to the invention begins with a step 310 of providing the structure Struct_0 obtained for example by means of the method 100 illustrated by figures 1 to 3.

[0064] At an epitaxy step 320, an Epi layer of gallium nitride GaN is formed by epitaxy on the TrLay layer of silicon carbide, known to be a good substrate for growth of GaN of excellent crystalline quality, the GaN layer thus formed being able to be considered monocrystalline.

[0065] In an assembly step 330, a substrate Sub3 is assembled to the structure Struct_0 via the Epi layer. The substrate Sub3 and the Epi layer are put into intimate contact and fixed to each other by molecular bonding, for example by direct hydrophilic bonding.

[0066] The substrate Sub3 is chosen to be sufficiently flat and smooth to be suitable for direct bonding with the Epi layer. It may be, for example, a monocrystalline silicon wafer or any other material used in the semiconductor field, such as sapphire, poly-SiC, mono or poly AIN or glass. The substrate Sub3 is also chosen for its compatibility with the manufacturing steps planned to be applied subsequently to the Epi layer, such as photolithography steps, plasma treatments, deposition of electrically insulating or conductive layers, ion implantations, heat treatments or other manufacturing steps used in the semiconductor industry.

[0067] In an irradiation step 340, a laser beam with a wavelength in the infrared, preferably between 9 and 11 pm, irradiates the GO layer through the substrate Sub2. The power density, the beam scanning speed and other parameters will be adapted by the operator to the transparency and the thickness of the material through which the GO layer is irradiated, as well as the thickness of the GO layer. Under the effect of this Irr irradiation, the GO layer can be degraded by decomposition as illustrated by [Fig.4] and indicated by "X" in [Fig.5]. Alternatively and possibly jointly, the Irr irradiation can induce the chemical reduction of the GO layer of graphene oxide to form reduced graphene oxide rGO, of much greater volume than graphene oxide. Reference may be made to the article by Tung Xuan Tran et al., “Laser-Induced Reduction of Graphene Oxide by Intensity-Modulated Line Beam for Supercapacitor Applications,” ACS Appl Mater Interfaces, 2018 Nov 21; 10(46):39777-39784. This increase in volume may help to move one of the other two layers flanking the GO layer away from each other.

[0068] The irradiation of step 340 thus allows a separation of the TrLay layer from the substrate Sub2 at a step 350. Thus a structure is formed comprising, in this order, the substrate Sub3, the epitaxial layer Epi, the transferred layer TrLay and remains of the GO layer formed from graphene oxide and / or reduced graphene oxide rGO. Steps 340 and 350 can also be considered as a single irradiation and separation step.

[0069] In a step 360, the remains of the GO layer as well as the TrLay layer are removed so as to release the Epi layer. This cleaning can be carried out by chemical mechanical polishing or CMP in English terminology. Thus a structure is formed which comprises, in this order, the Sub3 substrate and the GaN Epi layer.

[0070] At any time following the step of assembling the substrate Sub3 to the structure Struct_0, a stabilization heat treatment step 370 can be applied to the formed assembly. The stabilization heat treatment makes it possible to cure crystal defects present in the Epi layer and helps to consolidate the attachment between the Epi layer and the Sub3 substrate. This heat treatment can be provided to bring the stack to a temperature between 300°C and 600°C for a period of between 30 minutes and 10 hours. This heat treatment is preferably carried out by exposing the free face of the dielectric layer to a neutral gas atmosphere. Carried out after step 360 of removing the TrLay layer, this treatment can advantageously repair the damage caused to the Epi layer by this step 350A. At the end of the above steps, the structure Struct_l is obtained.

[0071] There are other methods for obtaining thin layers of gallium nitride and transferring them onto a receiving substrate, in particular those using Smart Cut™ technology. This technology is based on the formation of a weakening plane in a thick donor substrate, for example a monocrystalline wafer obtained from a massive monocrystalline ball of the target material. The depth of this weakening plane defines the thickness of a layer of material that can be detached from the wafer. This weakening plane is obtained by ion implantation of light species into the wafer, through one of its surfaces. However, the depth at which this implantation plane is located is limited by the maximum acceleration voltage of the ion implantation equipment available on the market.Thus, a layer that can be detached from the donor substrate sees its thickness limited by the maximum implantation depth of the ions forming the embrittlement plane.

[0072] On the other hand, the method 300 described above, applied here to gallium nitride, advantageously makes it possible to circumvent this thickness limitation while allowing easy transfer of the layer obtained. Indeed, the Epi layer can be epitaxially grown according to arbitrary thicknesses (while remaining subject to the critical epitaxy thickness), independent of the available ion implantation equipment. Then, a carrier substrate is assembled to the epitaxially grown layer.

[0073] Variants

[0074] The example presented above concerns the formation of a Struct_0 layer using silicon carbide SiC substrates Subi and Sub2. Other substrates may be used, as long as at least one of them is compatible with the formation of a graphene layer and its oxygenation treatment. Examples include substrates, but any other substrate satisfying the compatibility condition stated above could be used, such as those implemented in the semiconductor industry.

[0075] As regards the formation of the structure Struct_l, a condition in addition to that stated in the previous paragraph is that the substrate Sub2, carrying the TrLay layer via the GO layer, is substantially transparent to the wavelength used during the step of irradiating the GO layer. We can again cite silicon carbide and silicon substrates for Sub2. We speak of “substantially transparent” when at least 0% of the wavelength considered is transmitted through this substrate.

[0076] Alternatively, and although this is not a priori the preferred method, it would be possible to irradiate the GO layer through the Sub3 substrate and the TrLay layer. In this case, it is the Sub3 substrate which must be substantially transparent to the wavelength used during the GO layer irradiation step. In this case, silicon carbide and silicon substrates can again be mentioned for Sub3.

[0077] In this document, the figures are not necessarily to scale. Some features and components may be shown exaggerated relative to other components or in a somewhat schematic form, and some details of conventional elements may not be shown in the interest of clarity and conciseness.

[0078] Of course, the invention is not limited to the embodiments described and variant embodiments can be made without departing from the scope of the invention as defined by the claims.

Claims

Claims

1. Starting structure (Struct_0) designed to undergo separation by laser irradiation, comprising a substrate (Sub2), a transferred layer (TrLay), and a graphene oxide layer (GO, GO2) interposed between the substrate (Sub2) and the transferred layer (TrLay).

2. The structure of claim 1, wherein the substrate (Sub2) is transparent to infrared radiation.

3. The structure according to claim 1, wherein the substrate (Sub2) is transparent to radiation of wavelength between 9 and 11 pm.

4. The structure according to any one of claims 1 to 3, wherein the substrate is made of silicon Si or silicon carbide SiC.

5. The structure according to any one of claims 1 to 4, wherein the transferred layer is made of single-crystal silicon carbide SiC or sapphire.

6. Method (100) for manufacturing the starting structure (Struct_0) according to any one of claims 1 to 5, comprising: - a step (110, 120) of providing two substrates (Subi, Sub2); - a step (130, 140) of forming at least one layer (MG1, MG2) of multilayer graphene on at least one of the two substrates (Subi, Sub2); - a step (160, 170) of oxygenating the at least one layer of multilayer graphene so as to form at least one layer of graphene oxide (GO1, GO2); - a step (200) of assembling the two substrates (Subi, Sub2) via the at least one layer (GO1, GO2, GO) of graphene oxide; and - a step of detaching (210) a part of one (Subi) of the two substrates so as to leave the transferred layer (TrLay) on the other of the two substrates (Sub2).

7. The manufacturing method according to claim 6, wherein the assembly step (200) is carried out by direct contacting.

8. The manufacturing method according to claim 6 or 7, wherein a layer (MG1, MG2) of multilayer graphene is formed on each of the two substrates (Subi, Sub2).

9. The method of any one of claims 6 to 8, comprising

10.

11.

12.

13. furthermore a step (150) of ion implantation in the first substrate (Subi), so as to form a weakening plane (Frgl) in this first substrate (Subi) and thus define the transferred layer (TrLay). Method (300) for manufacturing an advanced structure (Struct_l) comprising a layer (Epi) formed by epitaxy on the transferred layer (TrLay) of the structure (Struct_0) according to claim 1, comprising the steps of: - providing (310) the structure (Struct_0) according to claim 1; - forming (320) by epitaxy the layer (Epi) on the transferred layer (TrLay) of the structure (Struct_0) provided; - assembling (330) a third substrate (Sub3) to the structure (Struct_0) by placing this third substrate (Sub3) in direct contact with the epitaxial layer (Epi); and - irradiate (340) the graphene oxide layer (GO) with infrared irradiation (Irr), so as to separate (350) the transferred layer (TrLay), the epitaxial layer (Epi) and the third substrate (Sub3) from the substrate (Sub2) of the starting structure (Struct_0). The method according to claim 10, wherein the irradiation (Irr) uses an electromagnetic wave of wavelength between 9 and 11 pm. The method according to claim 10 or 11, further comprising a step (360) of releasing the layer (Epi) following the separation step (350). The method of any one of claims 10 to 12, wherein the epitaxial layer is a layer of gallium nitride GaN.

Images