Detachable temporary substrate compatible with very high temperatures and method for transferring a working layer from said substrate

Abstract

The invention relates to a temporary substrate separable at a separation temperature higher than 1000°C and comprising: - a semiconductor working layer extending along a main plane, - a carrier substrate, - an intermediate layer arranged between the working layer and the carrier substrate, the thickness of the intermediate layer along an axis perpendicular to the main plane being less than 20 nm, - a bonding interface located within the intermediate layer or adjacent to the intermediate layer, - at least one atomic species of a gaseous substance, the atoms of which are distributed according to a concentration profile along an axis perpendicular to the main plane and have a maximum concentration higher than 10 21 / cm 3 When the temporary substrate is subjected to a temperature lower than the separation temperature, the atoms remain trapped in the intermediate layer and / or in an adjacent layer of the carrier substrate having a thickness less than or equal to 10 nm and / or in an adjacent sub-layer of the working layer having a thickness less than or equal to 10 nm, and when the temporary substrate is subjected to a temperature higher than or equal to the separation temperature, the atoms are intended to diffuse to the separation interface. The invention also relates to a method for manufacturing said temporary substrate. Finally, the invention relates to a method for transferring a working layer from a separable temporary substrate to a receiving substrate to form a composite structure.

Description

Technical Field

[0001] This invention relates to the field of semiconductor materials for microelectronic devices. Specifically, it relates to a temporary substrate separable at temperatures above 1000°C or even above 1200°C, and a method for manufacturing such a temporary substrate. The invention also relates to a method for transferring a working layer (e.g., a working layer made of single-crystal silicon carbide) from the temporary substrate to a receiving substrate. Background Technology

[0002] In recent years, attention has increased significantly on silicon carbide (SiC) because this semiconductor material can improve energy handling capabilities. SiC is being used more and more extensively in the production of innovative power devices to meet the rising demands of the electronics industry, particularly in applications such as electric vehicles.

[0003] Power devices and integrated power systems based on single-crystal silicon carbide (SiC) can manage higher power densities and achieve this with a smaller effective area compared to conventional silicon-based analogues. To further limit the size of power devices on SiC, it is advantageous to fabricate vertical elements rather than lateral elements. For this purpose, the structure must allow vertical conductivity between electrodes disposed on the front side of the SiC structure and electrodes disposed on the back side.

[0004] However, single-crystal SiC substrates intended for use in the microelectronics industry remain expensive and difficult to supply in large sizes. Therefore, it is advantageous to utilize thin-layer transfer solutions to fabricate composite structures, which typically consist of thin layers of single-crystal SiC on a less expensive carrier substrate. One well-known thin-layer transfer solution is Smart Cut. TM The method is based on implanting light ions and bonding them through direct contact. This method can, for example, fabricate a composite structure that allows vertical conductivity, comprising a thin layer of single-crystal SiC (c-SiC) taken from a donor substrate made of c-SiC and in direct contact with a carrier substrate made of polycrystalline SiC (p-SiC).

[0005] Moreover, the document US 8 436 363 is known, which describes a method for manufacturing a composite structure comprising a thin layer made of c-SiC arranged on a metal carrier substrate, the thermal expansion coefficient of which matches that of the thin layer. The manufacturing method comprises forming a buried weakening plane in a c-SiC donor substrate, delimiting the thin layer between the buried weakening plane and the front surface of the donor substrate. Next, a layer of metal (for example tungsten or molybdenum) is deposited on the front surface of the donor substrate to form a carrier substrate having a sufficient thickness to act as a stiffener. Finally, the method comprises separating along the buried weakening plane to form, on the one hand, a composite structure comprising the metal carrier substrate and the thin layer made of c-SiC, and, on the other hand, the rest of the c-SiC donor substrate.

[0006] However, such a manufacturing method is not suitable when the material forming the carrier substrate is p-SiC, which requires deposition at temperatures above 1200°C, the usual temperature for manufacturing p-SiC. In particular, at these high temperatures, the growth kinetics of the cavities present in the buried weakening plane is faster than that of the p-SiC layer, which cannot reach the thickness required for the stiffening effect before the onset of blistering, which involves deformation of the layer aligned perpendicularly to the cavities. SUMMARY

[0007] OBJECT OF THE INVENTION

[0008] The present invention relates to an alternative solution to these solutions in the prior art and aims to overcome the above-mentioned drawbacks completely or partially. In particular, the present invention relates to a temporary substrate separable at very high temperatures and to a related manufacturing method; it also relates to a method for transferring a working layer, in particular made of single-crystal silicon carbide, from a temporary substrate to a receiving substrate to form a composite structure.

[0009] BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a temporary substrate separable at a separation temperature higher than 1000°C and comprising:

[0010] - a semiconductor working layer extending along a main plane,

[0011] - a carrier substrate,

[0012] - an intermediate layer arranged between the working layer and the carrier substrate, having a thickness along an axis perpendicular to the main plane of less than 20 nm,

[0013] - a bonding interface located within or adjacent to the intermediate layer,

[0014] - atoms of at least one gaseous species distributed according to a concentration profile along an axis perpendicular to the main plane and having a concentration higher than 1016 21 / cm3 the atoms remain trapped in the intermediate layer and / or in the adjacent sublayer of thickness less than or equal to 10 nm of the carrier substrate and / or of the adjacent layer of thickness less than or equal to 10 nm of the working layer when the temporary substrate is subjected to a temperature lower than the detachment temperature, and are intended to diffuse to the detachment interface when the temporary substrate is subjected to a temperature higher than or equal to the detachment temperature.

[0015] Other advantageous and non-limiting features according to the application are considered alone or in any technically feasible combination:

[0016] • the working layer comprises silicon carbide, diamond and / or gallium nitride;

[0017] • the intermediate layer is formed of at least one material chosen from tungsten, nickel, titanium, aluminum, molybdenum, tantalum, titanium nitride, tantalum nitride, amorphous silicon;

[0018] • the gaseous substance is nitrogen, helium, argon, xenon and / or hydrogen;

[0019] • the carrier substrate comprises a material having a thermal expansion coefficient equal to or close to that of the working layer.

[0020] The application also relates to a method for manufacturing the temporary substrate described above, comprising:

[0021] a) a step of providing a donor substrate,

[0022] b) a step of implanting light ions chosen from hydrogen, helium or a combination of the two into the donor substrate to form a buried weakening plane in the donor substrate, the buried weakening plane delimiting a surface working layer from the front face of the donor substrate,

[0023] c) a step of providing a carrier substrate having a front face,

[0024] d) a step of depositing at least one thin film on the front face of the donor substrate and / or on the front face of the carrier substrate, the at least one thin film being intended to form the intermediate layer,

[0025] e) a step of joining the donor substrate and the carrier substrate so that the at least one thin film is arranged between the substrates, thereby forming the intermediate layer,

[0026] f) a step of separating along the buried weakening plane to form, on the one hand, the temporary substrate and, on the other hand, the remaining part of the donor substrate.

[0027] The manufacturing method further comprises the following step:

[0028] - before the deposition step d), introducing atoms of at least one gaseous substance into the donor substrate and / or into the carrier substrate up to a depth of less than or equal to 10 nm from their respective front face, or

[0029] - after the deposition step d), atoms of at least one gaseous species are introduced into the at least one thin film, or

[0030] - after the separation step f), atoms of at least one gaseous species are introduced into the intermediate layer.

[0031] Other advantageous and non-limiting features according to the application are considered alone or in any technically feasible combination:

[0032] • the step a) of providing a donor substrate comprises epitaxially growing a donor layer on an initial substrate to form the donor substrate;

[0033] • the initial substrate and the donor layer are made of silicon carbide, the step a) comprising forming a single-crystal conversion layer on the initial substrate before epitaxially growing the donor layer, so as to convert basal plane dislocation defects of the initial substrate into linear edge dislocation defects;

[0034] • the epitaxial growth is performed at a temperature above 1200°C, preferably between 1500°C and 1650°C;

[0035] • the step f) comprises a heat treatment at a temperature between 900°C and 1200°C.

[0036] Finally, the application relates to a method for transferring a working layer from the above-mentioned temporary substrate to a receiving substrate. The method comprises:

[0037] g) a step of forming a separable structure comprising the receiving substrate arranged on the working layer of the temporary substrate, the forming step comprising a treatment at a first temperature higher than or equal to 1000°C,

[0038] h) a step of separating the separable structure along a separation interface within or adjacent to the intermediate layer, the separating step comprising a heat treatment at a separation temperature higher than the first temperature, so as to form, on the one hand, a composite structure comprising the working layer arranged on the receiving substrate and, on the other hand, a carrier substrate.

[0039] Other advantageous and non-limiting features according to the application are considered alone or in any technically feasible combination:

[0040] • the step g) comprises depositing the receiving substrate on a free face of the working layer of the temporary substrate;

[0041] • the deposition of the receiving substrate is performed by a thermal chemical vapor deposition or an enhanced chemical vapor deposition or by an evaporation at a temperature higher than or equal to 1000°C, preferably higher than or equal to 1200°C;

[0042] • the formed receiving substrate is made of polycrystalline silicon carbide;

[0043] • the receiving substrate is a bulk substrate, step g) comprising bonding said receiving substrate to the free face of the working layer of the temporary substrate;

[0044] • the bonding comprises a direct bonding by molecular adhesion and a heat treatment at a temperature higher than or equal to 1000°C, or even higher than or equal to 1200°C;

[0045] • step h) comprises a heat treatment at a temperature higher than or equal to 1400°C, or even higher than or equal to 1500°C;

[0046] • the transfer method comprises a step i) of post-treatment of the composite structure, step i) comprising an operation of chemical cleaning and / or chemical etching and / or chemical-mechanical polishing of the free face of the working layer (front face of the composite structure);

[0047] • step i) comprises an operation of chemical cleaning and / or chemical etching and / or mechanical grinding and / or chemical-mechanical polishing of the free face of the receiving substrate (back face of the composite structure);

[0048] • the transfer method comprises a step g') of treatment of the separable structure before the separation step h), step g') comprising an operation of chemical cleaning and / or chemical etching and / or mechanical grinding and / or chemical-mechanical polishing of the back face of the receiving substrate;

[0049] • the transfer method comprises a step j) of finishing of the carrier substrate with the aim of reusing it as a new carrier substrate for a temporary substrate.

[0050] • the transfer method comprises the manufacture of an electronic component in or on the working layer of the composite structure, possibly after epitaxial growth of an additional layer on the working layer. BRIEF DESCRIPTION OF DRAWINGS

[0051] Other characteristics and advantages of the application will become apparent from the following detailed description of the application given with reference to the accompanying drawings wherein:

[0052] - Figure 1a and Figure 1b shows a separable temporary substrate according to the application, Figure 1b shows a close-up of the intermediate layer of said substrate;

[0053] - Figures 2a to 2f shows a method for manufacturing a separable temporary substrate according to the application;

[0054] - Figure 3a and Figure 3b shows a particular embodiment of step a) of the manufacturing method according to the application;

[0055] - Figure 4c' ,Figure 4d 、 Figure 4e and Figure 4f shows the steps of a method for manufacturing a separable temporary substrate according to a first embodiment of the application;

[0056] - Figure 5d' shows the steps of a method for manufacturing a separable temporary substrate according to a second embodiment of the application;

[0057] - Figure 6f' shows the steps of a method for manufacturing a separable temporary substrate according to a third embodiment of the application;

[0058] - Figures 7g to 7j shows the steps of a transfer method according to the application. DETAILED DESCRIPTION

[0059] In the description, the same reference signs can be used in the drawings for the same type of elements. The drawings are schematic representations for ease of understanding; they are not drawn to scale. In particular, the thickness of the layers along the z-axis is not drawn to scale with respect to the lateral dimensions along the x-axis and y-axis; the relative thicknesses of the layers with respect to each other in the drawings do not necessarily have to be respected.

[0060] The application relates to a temporary substrate 10 which is separable at a separation temperature higher than 1000°C, preferably even higher than 1200°C, higher than 1300°C, higher than 1400°C, or higher than 1500°C. By separable, it is meant that the temporary substrate 10 is able to be separated into two parts at very high temperature: in this case, it allows the transfer of a working layer 1 onto a final receiving substrate by separating said working layer 1 from a carrier substrate 3, the working layer 1 and the carrier substrate 3 being the two parts of the temporary substrate.

[0061] The temporary substrate 10 is preferably provided in the form of a wafer, with a diameter of 100 mm, 150 mm, 200 mm, or even possibly 450 mm, and a thickness generally between 300 pm and 800 pm. As shown in Figure 1a and Figure 1b The temporary substrate 10 has a front face 10a and a back face 3b extending along the main plane (x, y).

[0062] The temporary substrate 10 comprises a semiconductor working layer 1 arranged on an intermediate layer 2, the intermediate layer 2 itself being arranged on a carrier substrate 3. The temporary substrate 10 also comprises a bonding interface 4, which is located in or adjacent to the intermediate layer 2 (i.e. between the intermediate layer 2 and the working layer 1 or between the intermediate layer 2 and the carrier substrate 3).

[0063] The working layer 1 made of a semiconductor material is a layer intended to have elements made therein or thereon to solve a given application. Since the temporary substrate 10 is particularly suitable for semiconductor materials requiring very high processing temperatures, the working layer 1 advantageously comprises silicon carbide. Of course, the working layer 1 can also comprise one or more materials selected from diamond, binary or ternary III-V compounds requiring high manufacturing temperatures, such as for example gallium nitride or aluminum nitride, or II-VI compounds which also require high processing or manufacturing temperatures, typically higher than 1000°C or higher than 1200°C.

[0064] The working layer 1 is arranged on an intermediate layer 2 which is itself comprised in the temporary substrate 10. The intermediate layer 2 has a thickness along the z axis perpendicular to the main plane (x, y) which is less than 20 nm, or even less than 10 nm. This low thickness is important because it allows the temporary substrate 10 to remain in good mechanical strength and good compatibility with very high temperatures, even if the creep temperature or the melting temperature of one or more constituent materials of the intermediate layer 2 is lower than the separation temperature.

[0065] It should be noted that the intermediate layer 2 can extend continuously in parallel to the main plane (x, y), or discontinuously, for example in the form of nodules arranged side by side in a plane parallel to the main plane (x, y).

[0066] The intermediate layer 2 can be formed of at least one metallic or semiconducting material, for example selected from tungsten, nickel, titanium, aluminum, molybdenum, tantalum, titanium nitride, tantalum nitride and amorphous silicon.

[0067] The material of the intermediate layer 2 is chosen so that it does not diffuse into the working layer 1 and / or so that it does not react or hardly reacts, i.e. does not react or hardly reacts at very high temperatures applied during the implementation of the transfer process of the temporary substrate 10, over a very small thickness (less than 10 nm) of the working layer 1. This allows the integrity and the purity of the working layer 1 to be preserved.

[0068] The intermediate layer 2 is arranged on a carrier substrate 3 which also constitutes part of the temporary substrate 10. The carrier substrate 3 can be formed of any material compatible with the high temperatures required or targeted for processing the working layer 1. Preferably, the carrier substrate 3 comprises a material having a thermal expansion coefficient equal to or close to that of the working layer 1. For example, it can be chosen to have the same properties as the working layer 1, while exhibiting a lower crystal quality.

[0069] In the particular case of a working layer 1 made of silicon carbide, for example, the carrier substrate 3 can itself be formed of a single-crystal silicon carbide having a lower crystal quality than the working layer 1, or of a polycrystalline silicon carbide.

[0070] The temporary substrate 10 further comprises atoms 2a of at least one gaseous species, distributed according to a concentration profile 2b along the axis z, in which the maximum concentration is higher than 10 21 / cm 3 .

[0071] As will be described in further detail in the method for manufacturing the temporary substrate 10, these atoms 2a can be introduced at different times in the method and in different locations in the substrates and layers involved.

[0072] The concentration profile 2b of the atoms 2a can thus take various forms: Figure 1b An example is illustrated in Figure 2b, in which the atoms 2a are mostly located in the intermediate layer 2. Alternatively, the atoms 2a can be mostly located in a layer of the carrier substrate 3 adjacent to the intermediate layer 2 and having a thickness less than or equal to 10 nm: in other words, the atoms 2a are then mostly in the carrier substrate 3, but very close to the intermediate layer 2. As another alternative, the atoms 2a can be mostly located in a sub-layer of the working layer 1 adjacent to the intermediate layer 2, this sub-layer having a thickness less than or equal to 10 nm.

[0073] Regardless of the location of the atoms 2a, the concentration profile 2b must comprise a region in which the concentration of atoms 2a is at a maximum and reaches a value higher than or equal to 10 21 / cm 3 , or even higher than or equal to several 10 21 / cm 3 , generally 2 E 21 / cm 3 to 5 E 21 / cm 3 .

[0074] According to the application, when the temporary substrate 10 is subjected to a temperature lower than the separation temperature, the atoms 2a remain trapped in the intermediate layer 2 and / or in an adjacent layer of the carrier substrate 3 having a thickness less than or equal to 10 nm and / or in an adjacent sub-layer of the working layer 1 having a thickness less than or equal to 10 nm. When the temporary substrate 10 is subjected to a temperature higher than or equal to the separation temperature, these atoms 2a are intended to diffuse to the separation interface coinciding with or close to the bonding interface 4, said bonding interface 4 being in or adjacent to the intermediate layer 2.

[0075] The material of the intermediate layer 2 and the gaseous species are chosen so that:

[0076] - when the temporary substrate 10 is subjected to a temperature lower than the separation temperature, the atoms remain mostly trapped in the intermediate layer 2 due to the high solubility of said gaseous species in the intermediate layer 2, or

[0077] - When the temporary substrate 10 is subjected to a temperature lower than the separation temperature, the atoms remain mostly trapped in the adjacent thin layer of the carrier substrate 3 and / or in the adjacent thin sub-layer of the working layer 1, thanks to the effective barrier formed by the intermediate layer 2 against said species.

[0078] Thus, the trapped atoms 2a will mostly accumulate at the separation interface when the critical temperature (separation temperature) is exceeded and cause separation along said interface, as will be further described in the transfer method using the temporary substrate 10.

[0079] The gaseous species is preferably chosen from nitrogen, helium, argon, xenon and / or hydrogen.

[0080] The method for manufacturing the temporary substrate 10 will now be described with reference to Figure 2a to Figures 2g and Figure 3a and Figure 3b .

[0081] The manufacturing method first comprises a step a) of providing a donor substrate 11 having a front face 11a and a back face 11b. Figure 2a The donor substrate 11 will yield the working layer 1 of the temporary substrate 10; it therefore comprises at least the material forming the working layer 1.

[0082] The surface roughness of the front face 11a of the donor substrate 11 is advantageously chosen to be less than 1 nm Ra (average roughness), measured by atomic force microscopy (AFM) on a 20 pm x 20 pm scan area.

[0083] According to a first solution, the donor substrate 11 is a bulk substrate provided at the quality level required for the working layer 1, said layer coming directly from the donor substrate 11.

[0084] According to a second solution, step a) comprises epitaxially growing a donor layer 110 on an initial substrate 111 to form the donor substrate 11. The donor layer 110 preferably has a lower crystal defect density Figure 3a ) than the initial substrate 111.

[0085] In the particular case where the initial substrate 111 and the donor layer 110 are made of silicon carbide, step a) can comprise forming a single-crystal conversion layer 112 on the initial substrate 111 before epitaxially growing the donor layer 110, to convert basal plane dislocation defects of the initial substrate 111 into linear edge dislocation defects Figure 3b For example, the goal is to have a BPD defect density in the donor layer 110 lower than or equal to 1 / cm 2 .

[0086] The epitaxial growth of silicon carbide is carried out at a temperature higher than 1200°C, preferably between 1500°C and 1650°C. The precursors used are silane (SiH4), propane (C3H8) or ethylene (C2H4); the carrier gas can be hydrogen containing argon or not.

[0087] It should be noted that, prior to the epitaxial growth of the donor layer 110 (and / or of the conversion layer 112), a conventional procedure of cleaning and / or etching of the initial substrate 111 can be carried out, which aims at removing all or part of the particles, metals or organic contaminants or natural oxide layer that can be present on the front face thereof.

[0088] Next, the manufacturing method comprises a step b) of implanting light ions selected from the group of hydrogen, helium or a combination of the two substances into the donor substrate 11 (in particular into the donor layer 110, when it is present) to form a buried weakening plane 5( Figure 2b ) in said donor substrate 11. The buried weakening plane 5 delimits the surface working layer 1 with the front face 11a of the donor substrate 11.

[0089] As well known with reference to the Smart Cut TM method, these light substances will form microcavities distributed in a thin layer around the implantation depth, said thin layer being parallel to the front face 11a of the donor substrate 11, i.e. parallel to the plane (x, y) in the figures. For the sake of simplicity, this thin layer is referred to as the buried weakening plane 5.

[0090] The implantation energy of the light substances is chosen so as to reach a determined depth in the donor substrate 11, which matches the targeted thickness of the working layer 1. For example, hydrogen ions will be implanted at an energy between 10 keV and 250 keV and at a dose between 5 E 16 / cm 2 and 1 E 17 / cm 2 to delimit a working layer 1 having a thickness of about 100 nm to 1500 nm.

[0091] It should be noted that, prior to the ion implantation step of the light substances, a protective layer can be deposited on the front face 11a of the donor substrate 11. This protective layer can for example be composed of a material such as silicon oxide or silicon nitride.

[0092] Next, the method for manufacturing the temporary substrate 10 comprises a step c) comprising providing a carrier substrate 3( Figure 2c ).

[0093] As mentioned above, the carrier substrate 3 provides mechanical support in the temporary substrate 10 and is not intended to remain in the final composite structure 51 designed for a given application. Thus, the main characteristics of the carrier substrate 3 are preferably its low cost and its reliability as a mechanical support of the working layer 1.

[0094] Next, the manufacturing method comprises a step d) of depositing at least one thin film 21, 22 on the donor substrate 11 and / or on the carrier substrate 3. Figure 2d In other words, a first thin film 21 can be deposited on the front face 11a of the donor substrate 11; alternatively or additionally, a second thin film 22 can be deposited on the front face 3a of the carrier substrate 3. Figure 2d In the example illustrated, a first thin film 21 and a second thin film 22 are respectively deposited on the donor substrate 11 and on the carrier substrate 3.

[0095] It is noted that the at least one deposited thin film 21, 22 is intended to form the intermediate layer 2 of the temporary substrate 10.

[0096] The at least one deposited thin film 21, 22 has a thickness along the z axis perpendicular to the main plane (x, y) of less than 20 nm, or even less than 10 nm, for example between 0.3 nm and 10 nm.

[0097] By way of example, the at least one thin film 21, 22 can be formed of at least one material chosen from tungsten, nickel, titanium, aluminum, molybdenum, tantalum, titanium nitride, tantalum nitride, amorphous silicon.

[0098] The deposition of step d) can be carried out using any known technique, for example in particular direct liquid injection, plasma-enhanced chemical vapor deposition, thermal chemical vapor deposition (CVD), deposition by sputtering or by evaporation.

[0099] Next, the manufacturing method comprises a step e) of bonding the donor substrate 11 and the carrier substrate 3 so that the at least one thin film 21, 22 is arranged between said substrates 11, 3 and forms the intermediate layer 2. Figure 2e

[0100] The donor substrate 11 and the carrier substrate 3 are bonded through their respective front faces 11a, 3a, thereby forming a stack 311. As is well known per se, the two substrates can be bonded using direct bonding by molecular adhesion, i.e. in this case by placing the front faces of the substrates 11, 3 (either face or both faces provided with a thin film 21, 22) in direct contact. The bonding can be carried out at ambient temperature or at a temperature of less than 800°C and under ambient atmosphere or a controlled atmosphere, for example vacuum.

[0101] Before this contact, step e) can comprise conventional procedures of cleaning, surface activation or other surface preparation, which can improve the quality of the bonding interface 4 (low defect density, good adhesion quality).

[0102] The bonding or bonding interface 4 is located in the intermediate layer 2, or between this layer and the working layer 1, or between the intermediate layer 2 and the carrier substrate 3.

[0103] ​Next, the manufacturing method comprises a step f) comprising separating along the buried- weakened plane 5 to form on the one hand the temporary substrate 10 and on the other hand the remaining part 11' of the donor substrate. Figure 2f The front face 10a of the temporary substrate 10 is also the front face of the working layer 1 resulting from the donor substrate 11.

[0104] According to an advantageous embodiment, the separating step f) is performed by applying a thermal treatment to the stack 311 at a separating temperature. The microcavities present in the buried-weakened plane 5 follow a growth kinetics until a splitting wave starts, which will propagate throughout the extent of the buried-weakened plane 5 and cause the separation of the temporary substrate 10 from the remaining part 11' of the donor substrate. In practice, for a donor substrate 11 made of silicon carbide, the temperature can be between 900°C and 1200°C, depending on the implantation conditions of step b).

[0105] According to an alternative embodiment, the separating step f) is performed by applying a mechanical stress to the stack 311 after a complete or partial thermal treatment at a temperature between 900°C and 1200°C. The stress can be applied, for example, by inserting a tool (for example a blade) close to the buried-weakened plane 5. By way of example, the separating stress can be of the order of a few GPa, preferably higher than 2 GPa.

[0106] As is known per se, at the end of the separating step f), the front face 10a of the working layer 1 of the temporary substrate 10 has a surface roughness between 5 and 100 nm RMS (measured with an atomic force microscope (AFM) on a 20 pm x 20 pm scan area).

[0107] After the separation, the step f) can optionally comprise a treatment for smoothing and repairing the working layer 1. In particular, mention can be made of a thermal treatment under a controlled (oxidizing or reducing) atmosphere, a wet or dry chemical etching to remove damaged surface portions of the working layer 1, and / or a chemical-mechanical polishing of the front face of the working layer 1 to restore a good roughness level (for example, less than 0.5 nm RMS, or even less than 0.3 nm RMS, within an AFM field of view of 20 x 20 pm) and potentially remove damaged surface portions. Conventional cleaning procedures can also be applied to the temporary substrate 10, for example of SC1 / SC2 type (standard clean 1, standard clean 2) and / or cleaning by plasma of HF (hydrofluoric acid) and / or N2, Ar, CF4, etc. to further improve the quality of the front face 10a of the working layer 1.

[0108] Since the carrier substrate 3 is chosen to be compatible with the working layer 1 and to be mechanically and at high temperature stable, and since the intermediate layer 2 is chosen to have a very thin thickness, the thermal, mechanical or chemical treatments necessary to restore the working layer 1 to a high quality can be easily applied to the temporary substrate 10 without the risk of undesirable stresses or damage to the working layer 1.

[0109] It should be noted that step f) can be followed by a step of epitaxial growth of additional layers on the working layer 1 of the temporary substrate 10. Such a step is applied when the working layer needs a relatively large thickness, typically of the order of a few microns to tens of microns, for example a thickness of 5 pm to 50 pm. The epitaxial temperature is advantageously chosen to be lower than 1500 °C, or even lower than 1300 °C, to avoid premature initiation of the separation of the temporary substrate 10.

[0110] During or at the end of step f), which preferably includes a high-temperature thermal treatment, the intermediate layer 2 can undergo a physical and / or morphological change. It can be possible for at least one of the thin films 21, 22 to form nodules that are inserted into the abutment region between the material of the working layer 1 and the material of the carrier substrate 3: the intermediate layer 2 then forms from a discontinuous layer of nodules. The bonding interface 4 itself is therefore also significantly changed: it can be located in the nodules, between the nodules and the working layer 1, between the nodules and the carrier substrate 3 and / or between the working layer 1 and the carrier substrate 3. Alternatively, the intermediate layer 2 can remain in its continuous form all along the bonding interface 4.

[0111] The manufacturing method further comprises a step of introducing atoms 2a of at least one gaseous species into or in the vicinity of at least one of the thin films 21, 22. As mentioned above in the description of the temporary substrate 10, the gaseous species can be nitrogen, helium, argon, xenon and / or hydrogen. The atoms 2a of this gaseous species are those intended to be trapped in the adjacent layers of the intermediate layer 2 and / or of the carrier substrate 3 having a thickness less than or equal to 10 nm and / or in the adjacent sub-layers of the working layer 1 having a thickness less than or equal to 10 nm.

[0112] In the first embodiment illustrated in Figure 4c' , Figure 4d , Figure 4e and Figure 4f , this step of introducing atoms 2a is denoted c’) because it is carried out before step d) of depositing the thin films 21, 22. The atoms 2a are introduced into the donor substrate 11 and / or the carrier substrate 3 up to a shallower depth of less than 10 nm from their respective front faces 11a, 3a. Ion implantation can be carried out to introduce the atoms 2a in the form of ions into one or more of the substrates 11, 3, with an ion implantation energy generally lower than 10 keV, or even lower than 5 keV, and an implantation dose generally in the range 2 E 15 / cm 2 to a few 1 E 6 / cm2 The implanted regions 20 are thus formed in proximity to the surface of the front face 11a of the donor substrate 11 and / or in proximity to the surface of the front face 3a of the carrier substrate 3.

[0113] The steps d) to f) of the method are then carried out as described above and in Figure 4d 、 Figure 4e 、 Figure 4f are shown in the second embodiment.

[0114] The atoms 2a of the gaseous species are located in a thin layer (thickness less than or equal to 10 nm) of the carrier substrate 3 adjacent to the intermediate layer 2 and in a thin sub-layer (thickness less than or equal to 10 nm) of the working layer 1 adjacent to the intermediate layer 2; said adjacent layer and sub-layer stem from the implanted regions 20. Depending on the nature of the gaseous species and of the intermediate layer 2, the atoms 2a can remain trapped in the above-mentioned layer and sub-layer during the application of the thermal treatment to the temporary substrate 10 or become trapped in the intermediate layer 2, provided that the temperature to which the temporary substrate 10 is subjected is not higher than or equal to the detachment temperature (which is significantly higher than the separation temperature of step f)).

[0115] The atoms 2a of the gaseous species are distributed according to a concentration profile along the z axis perpendicular to the main plane (x, y), with a maximum concentration higher than 10 21 / cm 3 .

[0116] In the second embodiment shown in Figure 5d' , the step of introducing atoms 2a is designated d') because it is carried out after the step d) of depositing the thin film 21, 22.

[0117] As mentioned above, at least one thin film 21, 22 can be present on the donor substrate 11 and / or on the carrier substrate 3.

[0118] The atoms 2a are introduced into the at least one thin film 21, 22. Ion implantation can be carried out to introduce the atoms 2a in ionic form, with an ion implantation energy generally lower than 10 keV, or even lower than 5 keV, depending on the thickness of the thin film 21, 22 deposited in step d). The implantation dose is generally between 2 E 15 / cm 2 and several 1 E 16 / cm 2 .

[0119] In the intermediate layer 2, the atoms 2a of the gaseous species are distributed according to a concentration profile along the z axis, with a maximum concentration located at the implantation peak higher than 10 21 / cm 3 .

[0120] The steps e) to f) of the method are then carried out as described above and in Figure 2e ,Figure 2f ).

[0121] In Figure 6f' the third embodiment illustrated, the step of introducing atoms 2a is referred to as f') because it is performed after the separate step f).

[0122] Atoms 2a are introduced into the intermediate layer 2, for example by ion implantation. In this case, the ion implantation energy depends on the nature and thickness of the working layer 1, the ions will pass through the working layer 1 to reach the intermediate layer 2. The implantation dose is generally between 2 E 15 / cm 2 and several 1 E 16 / cm 2 .

[0123] Also in this case, the atoms 2a of the gaseous species are distributed according to a concentration profile along the z axis, with a maximum concentration expected to be higher than 10 21 / cm 3 at the implantation peak.

[0124] In any of the three embodiments described, the total dose of implanted ions is defined so that the concentration profile of atoms 2a exhibits a maximum concentration higher than 10 21 / cm 3 in the finished temporary substrate 10.

[0125] Introducing a high dose of atoms 2a of the gaseous species into the intermediate layer 2 and / or very close to the intermediate layer 2 allows the creation of a separation interface in the intermediate layer 2 or adjacent to the intermediate layer 2 during the transfer method of the application, as described below.

[0126] The application also relates to a method for transferring the working layer 1 from the temporary substrate 10 as described above to a receiving substrate 50. Reference is made to Figures 7g to 7j the transfer method is described.

[0127] The receiving substrate 50 is preferably provided in the form of a wafer, with a diameter of 100 mm, 150 mm, 200 mm, or even possibly 450 mm, and a thickness generally between 300 pm and 800 pm. It comprises a front face and a back face 50b opposite each other. The receiving substrate 50 is designed for the final application, so its physical and electrical properties are chosen specifically for the required specifications.

[0128] For power electronics applications in which the working layer 1 is made of high-crystalline-quality silicon carbide, for example, the receiving substrate 50 can in particular be made of polycrystalline silicon carbide exhibiting good electrical conductivity to provide a vertical conduction path.

[0129] The transfer method comprises a step g) of forming a separable structure 510 comprising a receiving substrate 50 arranged on the working layer 1 of the temporary substrate 10 Figure 7g It should be noted that, Figure 7g The temporary substrate 10 is shown in which the atoms 2a of the gaseous species are trapped in the intermediate layer 2; of course any other configuration described above can be implemented in which the atoms 2a are located in different positions.

[0130] Step g) comprises a treatment at a first temperature higher than or equal to 1000°C and advantageously lower than or equal to 1500°C.

[0131] According to a first embodiment, step g) comprises depositing the receiving substrate 50 on the free face 10a of the working layer 1 of the temporary substrate 10. The deposition can be carried out at a temperature higher than 1000°C, higher than or equal to 1200°C, or even higher than 1400°C, corresponding to the first temperature, in particular when it is necessary to deposit the receiving substrate 50 made of high-quality polycrystalline silicon carbide on the working layer 1 made of very high-quality single-crystal silicon carbide. Of course, other materials deposited at very high temperatures can be beneficial to form the receiving substrate 50.

[0132] For applications requiring electrical conduction between the working layer 1 and the receiving substrate 50, it is necessary to define a non-insulating interface between them. In other words, step g) is carried out so that the interface between the working layer 1 and the receiving substrate 50 is electrically conductive: the objective is for the specific resistance of the interface to be generally lower than 1 mohm.cm 2 Advantageously, in order to ensure the electrical conductivity of the interface, the native oxide present on the free face 10a of the working layer 1 is removed by HF (hydrofluoric acid) deoxidation (via a wet or dry process). Alternatively, the over-doping of the first nanometres of the deposited receiving substrate 50 can facilitate the electrical conductivity of the interface between the working layer 1 and said substrate 50.

[0133] It is also advantageous to apply a cleaning program to the temporary substrate 10 to remove all or part of the particulate, metallic or organic contaminants that can be present on its free faces 10a, 3b, before deoxidation and / or formation of the receiving substrate 50.

[0134] In the first embodiment, it should be noted that after the separation of step f), the working layer 1 of the temporary substrate 10 does not necessarily have to be polished to completely restore its surface roughness. The manufacture of the receiving substrate 50 by deposition or epitaxy at very high temperature, generally between 1100°C and 1500°C, can facilitate the repair and reconstitution of the surface of the working layer 1 and can further allow a residual roughness.

[0135] Since the carrier substrate 3 is chosen to be compatible with the working layer 1 and to be mechanically and at high temperature stable, and since the intermediate layer 2 is chosen to have a very small thickness, the thermal, mechanical or chemical treatments required to form the detachable structure 510 can be easily applied to the temporary substrate 10 without the risk of undesirable stresses or damage to the working layer 1.

[0136] In this first embodiment, the deposition of step g) can be performed using evaporation or chemical vapor deposition (CVD) techniques. Thermal CVD techniques such as atmospheric pressure CVD (APCVD) or low pressure CVD (LPCVD) or plasma enhanced CVD (PECVD) or direct liquid injection CVD (DLI-CVD) can be used.

[0137] To obtain the electrical conductivity properties required in the above-mentioned power applications, returning to the example of a receiving substrate 50 made of silicon carbide, this substrate can for example exhibit the following structural characteristics: polycrystalline structure, crystalline grains of the 3C SiC type, 111 orientation, average size of 1 pm to 50 pm, n-type doping so that the final resistivity is lower than or equal to 0.03 ohm.cm.

[0138] At the end of step g), the thickness of the receiving substrate 50 is generally greater than or equal to 50 pm, or even a thickness greater than or equal to 100 pm, for example of the order of 300 pm. The detachable structure 510 resulting from step g) comprises the receiving substrate 50 arranged on the working layer 1 which itself is comprised within the temporary substrate 10. The first temperature implemented for the manufacture of the receiving substrate 50 is lower than the detachment temperature, so that the atoms 2a of the gaseous species remain mostly trapped in the adjacent layers of the intermediate layer 2 and / or of the carrier substrate 3 having a thickness less than or equal to 10 nm and / or in the adjacent sub-layers of the working layer 1 having a thickness less than or equal to 10 nm.

[0139] According to a second embodiment in which the receiving substrate 50 is a bulk substrate, step g) comprises an operation of bonding said receiving substrate 50 to the free face 10a of the working layer 1 of the temporary substrate 10 to form the detachable structure 510.

[0140] The bonding operation can be performed using any known technique, in particular using direct bonding by molecular adhesion, or hot-press bonding or another type of bonding compatible with very high temperatures. In order to consolidate this bonding, step g) further comprises a heat treatment at a temperature higher than or equal to 1000°C, or even higher than or equal to 1200°C, corresponding to the first temperature.

[0141] Next, the transfer method according to the application comprises a step h) of separating the separable structure 510 along a separation interface located within or adjacent to the intermediate layer 2. This step forms on the one hand a composite structure 51 comprising the working layer 1 arranged on the receiving substrate 50, and on the other hand the carrier substrate 3. Figure 7h The separation step comprises a thermal treatment at a separation temperature higher than the detachment temperature of step f) and higher than the first temperature applied in step g). The separation temperature is higher than 1000°C.

[0142] Generally, in the particular case of an intermediate layer 2 comprising tungsten implanted with nitrogen atoms 2a, a working layer 1 and a carrier substrate 3 made of SiC, it is possible to have a separation temperature higher than or equal to 1400°C, or even higher than or equal to 1500°C, for example 1600°C or 1700°C.

[0143] The atoms 2a present in the temporary substrate 10 migrate during the thermal treatment of step h) and accumulate within the intermediate layer 2 at a separation interface coinciding with or close to the bonding interface 4. The gaseous species then generate pressurized microcracks which grow under pressure and lead to separation within the separable structure 510 over its entire area parallel to the main plane (x, y).

[0144] According to one particular embodiment, the intermediate layer 2 is segmented into nodules during step h) or in advance during a prior thermal treatment. These nodules are then inserted in the contiguous zone between the material of the working layer 1 and the material of the carrier substrate 3. The accumulation of gaseous species which occurs in step h) then occurs preferentially in said contiguous zone, leading to pressurized microcracks.

[0145] The separation phenomenon in the transfer method according to the application is particularly advantageous because it occurs only at the separation temperature (which is very high with respect to the temperature previously applied to the temporary substrate 10 or to the separable structure 510), thus providing usability with respect to several categories of steps for forming said separable structure 510. In particular, the high first temperature makes it possible to obtain a very high quality of the receiving substrate 50 (in the first embodiment) and / or a very high quality of the bonding of the receiving substrate 50 to the working layer 1 (in the second embodiment), without causing the separation interface at the intermediate layer 2 to develop prematurely.

[0146] Thus, it is possible to trigger the separation of the separable structure 510 and form the composite structure 51 in a second phase at a higher separation temperature.

[0147] Next, the transfer method according to the application can comprise a step i) of post-treatment of the composite structure 51, step i) comprising an operation of chemical cleaning and / or chemical etching and / or chemical-mechanical polishing of the free face of the working layer 1, i.e. of the front face 51a of the composite structure 51. It should be noted that chemical etching or polishing can be used to remove residues of the intermediate layer 2' from the front face 51a of the composite structure 51.

[0148] Step i) can also comprise an operation of chemical cleaning and / or chemical etching and / or mechanical grinding and / or chemical-mechanical polishing applied to the free face 50b of the receiving substrate 50, i.e. to the back face 50b of the composite structure 51.

[0149] Polishing or grinding of the edges of the composite structure 51 can also be carried out during this step i) to make its rounded profile and the shape of the edge waste compatible with the requirements of the microelectronic production process, in particular in the first embodiment where the receiving substrate 50 is formed by deposition.

[0150] Finally, step i) can comprise the epitaxial growth of an additional layer on the working layer 1 of the composite structure 51. This step is applied when the thickness of the working layer 1 transferred from the temporary substrate 10 is not sufficient to manufacture the element, or when a layer having a specific doping type or a specific composition is required on the surface of the working layer 1 for said element.

[0151] Optionally, the transfer method can comprise a step g') of treatment of the detachable structure 510 before the detachment step h), step g') comprising an operation of chemical cleaning and / or chemical etching and / or mechanical grinding and / or chemical-mechanical polishing of the back face 50b of the receiving substrate 50, and possibly grinding of the edges of the detachable structure 510. This makes it possible to treat and improve the shape and thickness of the receiving substrate 50 without risk of damaging the working layer 1 still buried in the detachable structure 510.

[0152] Finally, the transfer method according to the application can comprise a step j) of finishing the carrier substrate 3, in particular in order to reuse it as a new temporary substrate 10 carrier substrate (3) of the application. Such a finishing step is based on one or more treatments of the front face of the substrate 3 after the end of step h), by surface or edge chemical-mechanical polishing and / or by mechanical grinding and / or by wet or dry chemical etching. Figure 7j

[0153] Exemplary embodiments

[0154] ​According to one non-limiting exemplary embodiment, the initial substrate 111 provided in step a) of the manufacturing method is a wafer made of c-SiC of 4H polytype, with an orientation of 4.0° ± 0.5° with respect to the <11-20> axis, a diameter of 150 mm and a thickness of 350 pm. Prior to the epitaxial growth of the donor layer 110 made of c-SiC, a conventional cleaning procedure of RCA type (standard clean 1 + standard clean 2) followed by Caro’s acid (a mixture of sulfuric acid and hydrogen peroxide) and then HF (hydrofluoric acid) is performed on the initial substrate 111.

[0155] Growth is performed in an epitaxial chamber at a temperature of 1650 °C using precursors such as silane (SiH4) and propane (C3H8) or ethylene (C2H4), resulting in a c-SiC donor layer 110 of thickness 30 pm (growth rate: 10 pm / h). The donor layer 110 has a BPD defect density of about 1 / cm2. 2

[0156] The hydrogen ions implanted in step b) are implanted through the free surface of the donor layer 110 at an energy of 150 keV and a dose of 6 E 16H+ / cm 2 Thus a buried weakening plane 5 is created in the donor layer 110 at a depth of about 800 nm.

[0157] In step c) a carrier substrate 3 is provided made of single-crystal silicon carbide of low crystal quality, with a diameter of 150 mm and a thickness of 550 pm.

[0158] A cleaning procedure of RCA type + Caro’s acid is applied to the donor substrate 11 and the carrier substrate 3 in order to remove potential contaminants from their free faces.

[0159] Tungsten is deposited on the front face 11a of the donor substrate 11 and on the front face 3a of the carrier substrate 3 using chemical vapor deposition at a temperature of about 700 °C (step d)) to form a first thin film 21 and a second thin film 22, with a thickness of 0.5 nm.

[0160] Nitrogen is implanted into the thin film 21 of the donor substrate 11 (step d’)) at an implantation energy of 5 keV and a dose of 1 E 16 / cm 2 , so that the implantation peak (maximum concentration) is located in the thin film 21.

[0161] Next, step e) binds the implanted thin film 21 of the donor substrate 11 to the thin film 22 of the carrier substrate 3 along the bonding interface 4 by molecular adhesion, thereby forming a stack 311. The two thin films 21, 22 form the intermediate layer 2.

[0162] ​The separation step f) is carried out along the burying weakening plane 5 by applying a thermal treatment at 950°C for several tens of minutes, or even an hour. A temporary substrate 10 is thus formed with the surface working layer 1. The rest of the donor substrate 11' can be trimmed and reused for a new cycle.

[0163] A chemical-mechanical polishing operation is carried out to remove about 200 nm from the surface of the working layer 1, and a thermal treatment for repairing said working layer 1 at a temperature higher than or equal to 1200°C. During this step, the atoms 2a of the gaseous species remain mostly trapped in the intermediate layer 2.

[0164] In order to transfer the working layer 1 to a receiving substrate 50 to manufacture a composite structure 51, an LP-CVD deposition operation of polycrystalline silicon carbide is carried out on the working layer 1 of the temporary substrate 10 with a methylsilane precursor at a temperature of 1250°C for 120 minutes, so that the thickness of the receiving substrate 50 reaches 360 pm. Under these conditions, the receiver substrate 50 is a very high quality polycrystal (step g)). A step of grinding and / or polishing can be carried out to adjust the thickness of the receiving substrate 50 and possibly the shape of its peripheral edges. A separable structure 510 is thus produced.

[0165] The separation step h) corresponds to a thermal treatment applied to the separable structure 510 at 1700°C. A separation interface is formed in the intermediate layer 2 due to the diffusion of the nitrogen atoms 2a trapped in the intermediate layer 2 and their accumulation at the bonding interface 4 or very close to it forming pressurized microcracks, until it leads to the complete separation of the separable structure 510. Thus, one aspect obtained is a composite structure 51 comprising the working layer 1 arranged on the receiving substrate 50, and the other aspect is the carrier substrate 3. The composite structure 51 and the carrier substrate 3 each comprise a residue 2', 2" of the intermediate layer 2 which can be removed, for example, by polishing or by chemical etching.

[0166] If no mechanical grinding or chemical-mechanical polishing is carried out on the separable structure 510, it is preferable to apply a mechanical grinding or chemical-mechanical polishing to the back face of the composite structure 51.

[0167] In principle, the front face 51a of said structure 51 (corresponding to the free face 51a of the working layer 1) does not require conventional cleaning, since the quality of the layers and their low roughness are obtained in the temporary substrate 10.

[0168] A vertical element can then be manufactured on the composite structure 51, possibly after epitaxial growth of an additional layer on the working layer 1.

[0169] Under conditions similar to those described in the above examples, the material of at least one of the thin films 21, 22 can be amorphous silicon and the introduced atoms 2a can be argon or helium.

[0170] It is understood that the present application is not limited to the embodiments and examples described, which can be subject to variations without departing from the scope of the present application as defined in the claims.

Claims

1. Temporary substrate (10) able to be separated at a separation temperature higher than 1000°C and comprising: - a semiconductor working layer (1) extending along a main plane (x, y) comprising silicon carbide or comprising one or more materials chosen from the group consisting of diamond, gallium nitride, aluminum nitride and II-VI compounds requiring high processing or manufacturing temperatures higher than 1000°C, - a carrier substrate (3) comprising a material having a coefficient of thermal expansion equal to or close to the coefficient of thermal expansion of the working layer (1), - an intermediate layer (2) arranged between the working layer (1) and the carrier substrate (3) having a thickness along an axis (z) perpendicular to the main plane (x, y) of less than 10 nm and formed of at least one material chosen from the group consisting of tungsten, nickel, titanium, aluminum, molybdenum, tantalum, titanium nitride, tantalum nitride, amorphous silicon, - a bonding interface (4) located within or adjacent to the intermediate layer (2), - atoms (2a) of at least one gaseous species, these atoms (2a) being distributed according to a concentration profile (2b) along an axis (z) perpendicular to the main plane (x, y) and having a maximum concentration higher than 1010 21 / cm 3 When the temporary substrate (10) is subjected to a temperature lower than the separation temperature, said atoms (2a) remain trapped in the adjacent layers of the intermediate layer (2) and / or of the support substrate (3) having a thickness less than or equal to 10 nm and / or in the adjacent sub-layers of the working layer (1) having a thickness less than or equal to 10 nm, and when the temporary substrate (10) is subjected to a temperature higher than or equal to the separation temperature, said atoms (2a) are intended to diffuse to the separation interface.

2. The temporary substrate (10) according to claim 1, wherein the gaseous species being nitrogen, helium, argon, xenon and / or hydrogen.

3. Method for manufacturing a temporary substrate (10) according to any one of claims 1 to 2, comprising: a) a step of providing a donor substrate (11), b) a step of implanting light ions chosen from the group consisting of hydrogen, helium or a combination of both into the donor substrate (11) to form a buried weakening plane (5) in the donor substrate (11), the buried weakening plane (5) delimiting a surface working layer (1) with a front face (11a) of the donor substrate (11), c) a step of providing a carrier substrate (3) having a front face (3a), d) a step of depositing at least one thin film (21, 22) on the front face (11a) of the donor substrate (11) and / or on the front face (3a) of the carrier substrate (3), the at least one thin film being intended to form the intermediate layer (2), e) a step of joining the donor substrate (11) and the carrier substrate (3) so that the at least one thin film (21, 22) is arranged between the substrates (11, 3) thereby forming the intermediate layer (2), f) a step of separating along the buried weakening plane (5) to form on the one hand the temporary substrate (10) and on the other hand the remaining portion (11’) of the donor substrate, the manufacturing method further comprising the following step: - before the depositing step d), introducing atoms (2a) of at least one gaseous species into the donor substrate (11) and / or into the carrier substrate (3) up to a depth of less than or equal to 10 nm from their respective front faces (11a, 3a), or - after the depositing step d), introducing atoms (2a) of at least one gaseous species into the at least one thin film (21, 22), or - after the separating step f), introducing atoms (2a) of at least one gaseous species into the intermediate layer (2).

4. The method for manufacturing a temporary substrate (10) according to claim 3, wherein, The step f) comprises a heat treatment at a temperature between 900°C and 1200°C.

5. Method for transferring a working layer (1) from a temporary substrate (10) according to any one of claims 1 to 2 to a receiving substrate (50), the method comprising: g) a step of forming a separable structure (510) comprising a receiving substrate (50) arranged on the working layer (1) of the temporary substrate (10), the forming step comprising a treatment at a first temperature higher than or equal to 1000°C, h) a step of separating the separable structure (510) along a separation interface within or adjacent to the intermediate layer (2), the separation step comprising a heat treatment at a separation temperature higher than the first temperature, so as to form, on the one hand, a composite structure (51) comprising the working layer (1) arranged on the receiving substrate (50) and, on the other hand, a carrier substrate (3).

6. The method for transferring a working layer (1) from a temporary substrate (10) according to claim 5, wherein Step g) comprises depositing the receiving substrate (50) on the free face of the working layer (1) of the temporary substrate (10).

7. The method for transferring a working layer (1) from a temporary substrate (10) according to claim 6, wherein The deposition of the receiving substrate (50) is performed by means of a thermal chemical vapor deposition or an enhanced chemical vapor deposition or by evaporation at a temperature higher than or equal to 1000°C, preferably higher than or equal to 1200°C.

8. The method for transferring a work layer (1) from a temporary substrate (10) according to any one of claims 6 to 7, wherein, The receiving substrate (50) formed is made of polycrystalline silicon carbide.

9. The method for transferring a working layer (1) from a temporary substrate (10) according to claim 5, wherein, Step h) comprises a heat treatment at a temperature higher than or equal to 1400°C, or even higher than or equal to 1500°C.

10. The method for transferring a working layer (1) from a temporary substrate (10) according to claim 5, comprising a step i) of post-treatment of the composite structure (51), step i) comprising an operation of chemical cleaning and / or chemical etching and / or chemical-mechanical polishing of the free face of the working layer (1), i.e. of the front face (51a) of the composite structure (51).

11. The method for transferring a working layer (1) from a temporary substrate (10) according to claim 10, wherein Step i) comprises an operation of chemical cleaning and / or chemical etching and / or mechanical grinding and / or chemical-mechanical polishing of the free face of the receiving substrate (50), i.e. of the back face (50b) of the composite structure (51).

12. The method for transferring a working layer (1) from a temporary substrate (10) according to claim 5, comprising a step g') of treatment of the separable structure (510) before the separation step h), step g') comprising an operation of chemical cleaning and / or chemical etching and / or mechanical grinding and / or chemical-mechanical polishing of the back face (50b) of the receiving substrate (50).

13. The method for transferring a working layer (1) from a temporary substrate (10) according to claim 5, comprising manufacturing an electronic component in or on the working layer (1) of the composite structure (51).

14. The method for transferring a working layer (1) from a temporary substrate (10) according to claim 13, wherein The electronic component is manufactured after epitaxial growth of an additional layer on the working layer (1). The electronic component is manufactured after epitaxial growth of an additional layer on the working layer (1).

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