METHOD FOR MANUFACTURING A HOMOEPITAXIATED SILICON CARBIDE LAYER, ALLOWING THE FORMATION OF BPD-TYPE DEFECTS, AND ASSOCIATED COMPOSITE STRUCTURE

Abstract

The invention relates to a method for manufacturing an active layer of single-crystal silicon carbide by homoepitaxy on a composite structure, the method comprising the following steps: 1) the provision of a composite structure comprising a growth layer of single-crystal silicon carbide extending along a principal plane and disposed on a support substrate, the growth layer being delimited by a peripheral perimeter and having a first thickness along an axis normal to the principal plane;2) the formation of a local barrier in or on the growth layer, the local barrier extending at a distance and along the peripheral perimeter, and corresponding to a physical discontinuity of the growth layer chosen from among: - a raised relief induced by the presence of a material on the growth layer, said material being different from that of the growth layer, - a recessed relief corresponding to an etched area of ​​the growth layer, or - an amorphous domain or one of different crystallinity from the rest of the growth layer, the local barrier having a thickness, along the axis normal to the principal plane, less than the first thickness; 3) the epitaxial growth of the active layer on the growth layer. Figure to be published with the abstract: no figure;

Description

Title of the invention: A method for manufacturing a homoepitaxial silicon carbide layer, enabling the limitation of BPD-type defect formation, and associated composite structure. Scope of the invention

[0001] The present invention relates to the field of semiconductor materials, particularly composite structures comprising an active silicon carbide (SiC) layer fabricated by homoepitaxy on a free SiC surface. It relates in particular to a manufacturing process for limiting the formation of extended defects such as basal plane dislocation (BPD) and Shockley stacking faults (SSF) in said layer. It also relates to a composite structure on which an active layer of excellent quality can be homoepitaxially fabricated.

[0002] TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Silicon carbide (SiC) is a particularly interesting material for the fabrication of power devices, radio frequency devices, or devices operating at very high temperatures. To fabricate these devices, it is common practice to grow an active SiC layer 150 (for example, of polytype 4H or 6H) on the surface of a bulk substrate 1 (made of monocrystalline SiC) or a composite structure 100 comprising a thin layer 10 (made of monocrystalline SiC) transferred onto a support substrate 20 (advantageously made of polycrystalline SiC or lower-quality monocrystalline SiC), as illustrated in [Fig. 1]. A composite structure 100 can notably be fabricated using a known thin-film transfer technique such as the Smart Cut™ process.

[0004] During the epitaxy of the active layer 150, certain defects (called initial defects) present on the surface of the bulk substrate 1 or the thin layer 10 of the composite structure 100 can induce the formation of local SiC 3C polytype inclusions or misoriented SiC 4H zones. The stress field created by the local inclusions triggers the sliding of basal plane dislocations (BPDs), giving rise to a complex network of Shockley stacking faults (SSFs) and partial dislocations in the epitaxially formed active layer. These defects are highly critical because they can, among other things, cause the deterioration of devices subsequently fabricated in the active layer, through a bipolar degradation mechanism. Furthermore, each defect can readily extend through thermal activation and electron-hole pair recombination, along a direction parallel to the epitaxial surface.This significantly worsens the situation, as multiple devices can be impacted by each widespread defect.

[0005] SUBJECT OF THE INVENTION

[0006] The present invention relates to a method for manufacturing a single-crystal silicon carbide active layer by homoepitaxy, said method making it possible to limit the density of extended defects of the basal plane dislocation (BPD) and Shockley stacking faults (SSF) type in said layer. The manufacturing method comprises, in particular, a step of forming a peripheral local barrier on or in the growth layer of a composite structure, to prevent the extension of inclusions generated in the active layer into extended defects of the BPD and SSF type. The invention also relates to a composite structure equipped with said local barrier.

[0007] BRIEF DESCRIPTION OF THE INVENTION

[0008] The invention relates to a method for manufacturing a single-crystal silicon carbide active layer by homoepitaxy on a composite structure, the method comprising the following steps:

[0009] 1) the provision of a composite structure comprising a growth layer in single-crystal silicon carbide extending along a principal plane and arranged on a support substrate, the growth layer being delimited by a peripheral perimeter and having a first thickness along an axis normal to the principal plane;

[0010] 2) the formation of a local barrier in or on the growth layer, the barrier local extending at a distance and along the peripheral perimeter, and corresponding to a physical discontinuity in the growth layer chosen from:

[0011] - a raised relief induced by the presence of a material on the growth layer, said material being different from that of the growth layer,

[0012] - a recessed relief corresponding to an engraved area of ​​the growth layer, or

[0013] - an amorphous domain or a domain of different crystallinity from the rest of the layer growth,

[0014] the local barrier having a thickness, along the axis normal to the principal plane, less than the first thickness;

[0015] 3) the epitaxial growth of the active layer on the growth layer, the layer active exhibiting a second layer.

[0016] According to other advantageous and non-limiting features of the invention, taken alone or in any technically feasible combination: • the first thickness is between 50nm and Ipm; • the peripheral perimeter of the growth layer is located on average between 0.5mm and 2mm from the peripheral edge of the substrate supporting the composite structure; • the local barrier is located more than 0.1mm, more than 0.5mm, more than 1mm, more than 2mm, more than 3mm, or even more than 5mm from any point on the peripheral perimeter of the growth layer; • the thickness of the local barrier is less than 70%, 50%, 30%, 20%, or even 10% of the first thickness; • the recessed relief is achieved by mechanical abrasion, laser abrasion, wet engraving or dry engraving of the growth layer; • the amorphous domain or of different crystallinity from the rest of the growth layer is produced by laser amorphization or by ion implantation; • the bumpy relief is produced by local deposition of a material such as tungsten nitride or tungsten disilicide; • the second thickness is greater than or equal to 5 µm, 1 µm, or even 30 µm.

[0017] The invention further relates to a composite structure comprising a single-crystal silicon carbide growth layer extending along a principal plane and disposed on a support substrate, the growth layer being delimited by a peripheral perimeter and having a first thickness along an axis normal to the principal plane; the composite structure is remarkable in that it comprises a local barrier in or on the growth layer, the local barrier extending at a distance and along the peripheral perimeter, and corresponding to a physical discontinuity of the growth layer selected from: - a raised relief caused by the presence of a material on the growth layer, said material being different from that of the growth layer, - a hollow relief corresponding to an engraved area of ​​the growth layer, or - an amorphous domain or one with a different crystallinity from the rest of the growth layer. The local barrier has a thickness, along the axis normal to the principal plane, that is less than the first thickness.

[0018] According to other advantageous and non-limiting features of the invention, taken alone or in any technically feasible combination: - the local barrier is located more than 0.1mm, more than 0.5mm, more than 1mm, more than 2mm, more than 3mm, or even more than 5mm from any point on the peripheral perimeter of the growth layer; - the thickness of the local barrier is less than 70%, 50%, 30%, 20%, or even 10% of the first thickness; - the composite structure further comprises an active layer of raw single-crystal silicon carbide by homoepitaxy on the growth layer, the active layer having a second thickness; - the second thickness is greater than or equal to 5pm, to 1Opm, or even to 30pm. BRIEF DESCRIPTION OF THE FIGURES

[0019] Other features and advantages of the invention will become apparent from the detailed description of the invention which follows with reference to the accompanying figures in which:

[0020] [Fig-1] The [Fig.1] shows a solid substrate, a composite structure with and without epitaxial layer;

[0021] [Fig.2] [Fig.2] shows an example of a surface map of a layer active raw on a composite structure; the dark areas correspond to extensive defects (BPD network, SSF, partial dislocations);

[0022] [Fig. 3] Figure 3 shows an image of an extensive defect, obtained by imaging by photoluminescence: we can see in the bottom left of the image a jagged area (the black region being the crown of the composite structure, devoid of a growth layer), at the level of which an inclusion has caused an extensive defect;

[0023] [Fig.4a]

[0024] [Fig.4b]

[0025] [Fig.4c]

[0026] [Fig.4d]

[0027] [Fig. 4e] Figures 4a, 4b, 4c, 4d, 4e show sub-steps in the manufacture of a composite structure according to the method according to the invention;

[0028] [Fig. 5] Fig. 5 presents an example of a local barrier formed on and / or in the growth layer of a composite structure, according to the method according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention relates to a method for manufacturing an active layer 150 of single-crystal silicon carbide, by homoepitaxy on the growth layer 10 of a composite structure 100.

[0030] The applicant observed that the extensive defects mentioned in the introduction, resulting from local inclusions formed during epitaxy on initial defects in the growth layer 10, become extremely significant for epitaxially formed active layers with a thickness greater than 1 µm, and even very critical for thicknesses greater than 30 µm. In a composite structure 100, the initial defects may, in particular, correspond to: - holes passing through the growth layer 10, induced by a local transfer problem, - serrations around the edge of the growth layer, or - local deformations of the growth layer.

[0031] Figure 2 shows an example of a map of defects detected on the surface of a 30 pm raw active layer on a composite structure 100: note the very high density of extended defects, originating mainly from the periphery of the layer. growth 10 and having propagated thermally towards the center of the structure. Figure 3 shows an example of an inclusion from which a network of BPD and SSF defects propagated to generate an extensive defect. The image was obtained by photoluminescence microscopy. The black region in the lower left of the image lacks a growth layer 10, and the jagged appearance of the periphery 10c of the growth layer 10 is noticeable. These jagged edges, as stated above, constitute initial defects capable of giving rise to local inclusions during epitaxial growth, and consequently, to extensive defects.

[0032] The process according to the invention aims to provide an active layer 150 of improved quality by implementing a local barrier 130 in the growth layer 10, capable of blocking the extension of BPD and SSF type defects; this local barrier is defined to take into account a specificity of composite structures 100, namely that the growth layer 10 has an irregular peripheral perimeter 10c, which is a major source of initial defects likely to give rise to extended killer defects after epitaxy of the active layer 150.

[0033] The first step of the process consists of providing a composite structure 100 comprising a growth layer 10 of single-crystal silicon carbide extending along a principal plane (x,y) and deposited on a support substrate 20. The composite structure 100 is preferably in the form of a circular wafer with a diameter of 100 mm, 150 mm, 200 mm, or even more. However, it could be in any other form allowing for its subsequent processing for the manufacture of components. The thickness of the structure 100 extends along the z-axis in the figures.

[0034] As indicated in the introduction, the composite structure 100 can be developed by a layer transfer technique such as the Smart Cut™ process.

[0035] In a first substep a), a donor substrate 1 of single-crystal silicon carbide and a support substrate 20 are provided ([Fig. 4a]). The single-crystal SiC can be of polytype 4H, 6H, or 3C. The donor substrate 1 is preferably in the form of a wafer with a diameter identical to, or very close to, that of the support substrate 20 with which it will be subsequently assembled, and a thickness typically between 300 µm and 800 µm. It has a front face la and a back face 1b. The surface roughness of the front face la is advantageously chosen to be less than 1 µm RMS, or even less than 0.5 nm RMS, measured by atomic force microscopy (AFM) on a 20 µm x 20 µm scan. The type of doping and the resistivity of the donor substrate 1 are defined according to the application and the devices intended. The support substrate 20 corresponds to the mechanical support of the future composite structure 100.It is advantageously formed in polycrystalline silicon carbide (p-SiC) or in SiC. single crystal of lower crystalline quality. Its electrical properties (type and level of doping) can also be chosen according to the intended application.

[0036] The second substep b) comprises the implantation of light species in a donor substrate 1 to form a buried fragile plane 11, which, along with a front face of the donor substrate 1, delimits the surface layer to be transferred 10' ([Fig. 4b]). The light species are preferably hydrogen and / or helium and are implanted in the donor substrate 1 at a depth consistent with the thickness of the target growth layer 10. These light species will form microcavities around the determined depth, distributed in a thin layer parallel to the free surface of the donor substrate 1, i.e., parallel to the (x,y) plane in the figures. For simplicity, this thin layer is called the buried fragile plane 11. The implantation energy of the light species is chosen to reach the target depth.For example, hydrogen ions will be implanted at an energy between 10 keV and 250 keV, and at a dose between 5E16 / cm2 and 1E17 / cm2, to delimit a surface layer 10' with a thickness on the order of 100 nm at 1500 nm. Note that a protective layer may be deposited on the front face of the donor substrate 1, prior to the ion implantation step. This protective layer may be composed of a material such as silicon oxide or silicon nitride, for example. It may be removed prior to the next substep.

[0037] The third substep c) corresponds to the assembly of the support substrate 20, on the side of its front face 20a, with the implanted donor substrate 1, also on the side of its front face ([Fig. 4c]). The lateral dimensions in the principal plane (x,y) of the support substrate 20 (its diameter in particular) are the same as those of the composite structure 100. The support substrate 20 typically has a thickness between approximately 50 µm and several hundred micrometers, for example between 50 µm and 650 µm, or between 100 µm and 450 µm, or between 200 µm and 350 µm.

[0038] The assembly is carried out by direct bonding, by molecular adhesion, along a bonding interface 40. Optionally, an intermediate layer may be formed on the front face of the donor substrate 1, before or after the introduction of the light species, and in any case, before the assembly phase. This intermediate layer may be made of a dielectric, semiconductor, or metallic material (such as, for example, silicon dioxide, silicon, silicon carbide, tungsten, titanium, etc.). Optionally, an intermediate layer may also be deposited on the face 20a to be assembled of the support substrate 20, prior to assembly; it may be of the same or different nature as the intermediate layer mentioned for the donor substrate 1. An intermediate layer may optionally be deposited on both of the two substrates 1.20 to be assembled. The intermediate layer(s) is / are intended to be buried in the bonded assembly 50 after assembly, and ultimately, in the composite structure 100.

[0039] Direct molecular adhesion bonding does not require an adhesive material, as bonds are established at the atomic scale between the surfaces being joined. Several types of molecular adhesion bonding exist, differing in particular by their temperature, pressure, atmospheric conditions, or pretreatments prior to contacting the surfaces. Examples include room-temperature bonding with or without prior plasma activation of the surfaces to be joined, atomic diffusion bonding (ADB), surface-activated bonding (SAB), etc.

[0040] The assembly substep may include, prior to bringing the faces la,20a to be assembled into contact, conventional sequences of chemical cleaning (for example, RCA cleaning), surface activation (for example, by oxygen or nitrogen plasma) or other surface preparations (such as scrubbing), which may promote the quality of the bonding interface 40 (low defect, high adhesion energy).

[0041] It should be noted that the presence of a chamfer, at the level of the peripheral edge 20c of the support substrate 20 and the peripheral edge of the donor substrate 1, generates a non-bonded peripheral ring (not shown in [Fig.4c]), a ring into which the surface layer 10' will not be transferred.

[0042] The fourth substep d) corresponds to a separation along the buried fragile plane 11 to form an intermediate composite structure 100' comprising the surface layer 10' after transfer and the supporting substrate 20, on the one hand, and the remainder of the donor substrate 1', on the other hand ([Fig. 4d]). The separation along the buried fragile plane 11 is usually achieved by applying a heat treatment at a temperature between 800°C and 1200°C. Such a heat treatment induces the development of cavities and microcracks in the buried fragile plane 11, and their pressurization by the light species present in gaseous form, until a fracture propagates along said fragile plane 11. Alternatively or concurrently, mechanical stress can be applied to the bonded assembly and in particular to the buried fragile plane 11, so as to propagate or help to propagate mechanically the fracture leading to the separation.

[0043] The free surface 10'a of the surface layer 10' is usually rough after separation: for example, it has a roughness between 5 nm and 100 nm RMS. The surface layer 10' is delimited, in the (x,y) plane, by a peripheral boundary 10'c, set back from the peripheral edge 20c of the supporting substrate. 20. As mentioned previously, this peripheral 10'c can be serrated and irregular; on average, it is spaced from the peripheral 20c edge by a distance (width of the unbonded peripheral crown) of between 0.5mm and 2mm.

[0044] Finally, the fifth substep e) comprises the application of thermal, mechanical, and / or chemical treatments to the free surface 10'a of the surface layer 10', to form the composite structure 100 equipped with the growth layer 10 made of single-crystal silicon carbide ([Fig. 4e]). In particular, this substep e) may include a mechano-chemical smoothing treatment of the free surface 10'a of the surface layer 10'. A removal, for example, of between 50 nm and 300 nm makes it possible to effectively restore the surface condition of the layer, typically leading to a roughness less than or equal to 0.5 nm RMS, or even less than or equal to 0.1 nm RMS (AFM scan 10 x 100 µm² or 20 x 20 µm²). Substep e) may also include at least one heat treatment at a temperature between 1200°C and 1800°C.Such a heat treatment is applied to remove residual light species from the surface layer 10' and to promote the rearrangement of its crystalline lattice, thus forming a high-quality growth layer 10. It also strengthens the bonding interface 40.

[0045] At this stage of the process, the growth layer 10 of the composite structure 100 has a first thickness typically ranging from a few tens of nm to a few hundred nm, for example, between 50 nm and 1000 nm. The growth layer 10 is delimited by a peripheral rim 10c exhibiting irregularities, such as serrations. In general, said peripheral rim 10c is located, on average, between 0.5 mm and 2 mm from the peripheral edge 20c of the support substrate 20 of the composite structure 100.

[0046] The method according to the invention then comprises a second step corresponding to the formation of a local barrier 130 in or on the growth layer 10. This local barrier corresponds to a physical discontinuity in the growth layer 10 and extends at a distance and continuously along the peripheral perimeter 10c ([Fig. 5] (i) (ii)). Preferably, it is located more than 0.1 mm, more than 0.5 mm, more than 1 mm, or even more than 2 mm, more than 3 mm, or even more than 5 mm from any point on the peripheral perimeter 10c of the growth layer 10.

[0047] The barrier 130 can follow, in the main plane (x,y), the path of the peripheral perimeter 10c, or follow a substantially different path, for example more regular (perfectly circular) or more irregular, to bypass specific initial defects present in the immediate vicinity of the peripheral perimeter 10c of the growth layer 10.

[0048] According to a first embodiment, the physical discontinuity can be expressed as a raised relief induced by the presence of a material disposed on the layer of growth 10, said material being different from that of growth layer 10. Such relief can for example be achieved by local deposition of a material such as tungsten nitride or tungsten disilicide (WSi2).

[0049] According to a second embodiment, the physical discontinuity characterizing the local barrier 130 can be translated into a hollow relief, which can in particular be produced by mechanical abrasion (sawing, honing), by laser abrasion, by wet etching or by dry etching of the growth layer 10, locally ([Fig.5] (ii) and (iii)).

[0050] Finally, according to a third embodiment, the physical discontinuity can correspond to an amorphous domain or a domain of different crystallinity from the rest of the growth layer 10, for example produced by laser amorphization or by ion implantation.

[0051] The local barrier 130 has a thickness, along a z-axis normal to the principal plane (x,y), that is less than the first thickness, in particular less than 70%, 50%, 30%, 20%, or even 10% of the first thickness. Its width, in the principal plane (x,y) and along a radial direction, can vary between 0.1 and 1000 micrometers.

[0052] The applicant has identified that the aforementioned characteristics of the local barrier 130 make it possible to block the extension of basal plane dislocations (BPD) and Shockley stacking fault networks (SSF) from local inclusions of SiC 3C polytype or disoriented SiC 4H zones that may form, during epitaxy, on irregularities of the peripheral boundary 10c of the growth layer 10. The presence of this local barrier 130 thus prevents killer defects of the BPD and SSF type from extending from the boundary 10c towards the center of the growth layer 10, and allows the obtaining of a high-quality active layer 150, after epitaxial growth.

[0053] The physical discontinuity of the growth layer 10, which constitutes the local barrier 130, effectively prevents the propagation of BPD and SSF defects. Without being bound by this explanation, it is suggested that the thickness of the barrier 130, being less than the thickness of the growth layer 10, is an important parameter for preventing the propagation of new radially extended defects from said barrier 130.

[0054] The process according to the invention finally includes a third step corresponding to the epitaxial growth of the active layer 150 on the growth layer 10, the active layer having a second thickness, typically greater than or equal to 5pm, 10pm, or even 30pm.

[0055] This epitaxial growth of silicon carbide is carried out in the classic temperature range, namely between 1500°C and 1900°C.

[0056] The physical discontinuity constituted by the local barrier 130 induces locally perturbed epitaxial growth: in particular, the barrier 130 extends into the thickness of the active layer 150, as it grows, in the form of a "wall" including stacking faults (SF), favorable to blocking the sliding of BPD dislocations.

[0057] The disruption of epitaxial growth linked to barrier 130 nevertheless remains local and the rest of the active layer 150 grows according to the crystalline structure of the growth layer 10.

[0058] In the example illustrated in [Fig. 5] (iii) and (iv), the composite structure 100 provided in the first step of the process comprises a 600 nm thick c-SiC growth layer 10, deposited on a 350 µm thick p-SiC support substrate 20. The local barrier 130, produced in the second step of the process, corresponds to a recessed relief created by local mechanical abrasion etching: its depth is approximately 300 nm and its width approximately 2 µm. It is located 1 mm from the peripheral edge 10c of the growth layer 10. In [Fig. 5] (iii), a hole passing through the growth layer 10 (initial defect) can be observed above the barrier 130. During the third step of the process, an active layer 150 of 30 pm is produced by homoepitaxy at a temperature of 1550 °C. At the initial defect, a local inclusion has formed ([Fig.5] (iv)): on either side of this inclusion, an extended defect of the BPD and SSF type appears.The barrier 130 prevents the extension of the defect towards the center of the active layer 150 (downwards in the figure).

[0059] Of course, the invention also relates to the composite structure 100 comprising the growth layer 10, disposed on the support substrate 20, and the local barrier 130 formed on or in said growth layer 10. It also relates to the composite structure 100 provided with the active layer 150 raw by homoepitaxy on the growth layer 10, and whose local barrier 130 allows obtaining an excellent quality of active layer 150.

[0060] Of course, the invention is not limited to the embodiments and examples described, and alternative embodiments can be made without departing from the scope of the invention as defined by the claims.

Claims

Demands

1. Method of manufacturing an active layer (150) of single-crystal silicon carbide by homoepitaxy on a composite structure (100), the method comprising the following steps: 1) the provision of a composite structure (100) comprising a growth layer (10) of single-crystal silicon carbide extending along a principal plane (x,y) and disposed on a support substrate (20), the growth layer (10) being delimited by a peripheral perimeter (10c) set back from a peripheral edge (20c) of the support substrate (20), and having a first thickness along an axis normal (z) to the principal plane (x,y), the composite structure (100) including a bonding interface (40) between the growth layer (10) and the support substrate (20);2) the formation of a local barrier (130) in or on the growth layer (10), the local barrier extending at a distance and along the peripheral perimeter (10c), and corresponding to a physical discontinuity of the growth layer (10) chosen from: - a raised relief induced by the presence of a material on the growth layer (10), said material being different from that of the growth layer, - a hollow relief corresponding to an etched area of ​​the growth layer (10), or - an amorphous domain or of different crystallinity from the rest of the growth layer (10), the local barrier (130) having a thickness, along the axis (z) normal to the principal plane (x,y), less than the first thickness; 3) the epitaxial growth of the active layer (150) on the growth layer (10) provided with the local barrier (130), the active layer (150) having a second thickness.

2. A manufacturing method according to claim 1, wherein the first thickness is between 50nm and Ipm.

3. A manufacturing method according to any one of claims 1 and 2, wherein the peripheral perimeter (10c) of the growth layer (10) is located on average between 0.5mm and 2mm from the peripheral edge (20c) of the support substrate (20) of the composite structure (100).

4. A manufacturing method according to any one of claims 1 to 3, wherein the local barrier (130) is located at more than 0.1 mm, at more than 0.5mm, more than 1mm, more than 2mm, more than 3mm, or even more than 5mm from any point on the peripheral perimeter (10c) of the growth layer (10).

5. A manufacturing method according to any one of claims 1 to 4, wherein the thickness of the local barrier (130) is less than 70%, 50%, 30%, 20%, or even 10% of the first thickness.

6. A manufacturing method according to any one of claims 1 to 5, wherein the recessed relief is achieved by mechanical abrasion, laser abrasion, wet etching or dry etching of the growth layer (10).

7. A manufacturing method according to any one of claims 1 to 5, wherein the amorphous domain or domain of different crystallinity from the rest of the growth layer (10) is produced by laser amorphization or by ion implantation.

8. A manufacturing method according to any one of claims 1 to 5, wherein the raised relief is achieved by local deposition of a material such as tungsten nitride or tungsten disilicide.

9. A manufacturing method according to any one of claims 1 to 8, wherein the second thickness is greater than or equal to 5pm, 10pm, or even 30pm.

10. Composite structure (100) comprising a growth layer (10) of single-crystal silicon carbide extending along a principal plane (x,y) and disposed on a support substrate (20), the growth layer (10) being delimited by a peripheral boundary (10c) set back from a peripheral edge (20c) of the support substrate (20), and having a first thickness along an axis normal (z) to the principal plane (x,y), the composite structure including a bonding interface (40) between the growth layer (10) and the support substrate (20), and being characterized in that it comprises a local barrier (130) in or on the growth layer (10), the local barrier extending at a distance and along the peripheral boundary (10c), and corresponding to a physical discontinuity of the growth layer (10) selected from: - a raised relief induced by the presence of a material on the growth layer (10),said material being different from that of the growth layer, - a recessed relief corresponding to an engraved area of ​​the growth layer (10), or, - an amorphous domain or of different crystallinity from the rest of the growth layer (10), the local barrier (130) having a thickness, along the axis (z) normal to the principal plane (x,y), less than the first thickness.

11. Composite structure (100) according to claim 10, wherein the local barrier (130) is located more than 0.1mm, more than 0.5mm, more than 1mm, more than 2mm, more than 3mm, or even more than 5mm from any point on the peripheral perimeter (10c) of the growth layer (10).

12. Composite structure (100) according to any one of claims 10 and 11, wherein the thickness of the local barrier (130) is less than 70%, 50%, 30%, 20%, or even 10% of the first thickness.

13. Composite structure (100) according to any one of claims 10 to 12, further comprising an active layer (150) of single-crystal silicon carbide raw by homoepitaxy on the growth layer (10), the active layer (150) having a second thickness.

14. Composite structure (100) according to claim 13, wherein the second thickness is greater than or equal to 5pm, 1Opm, or even 30pm.

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