DONOR SUBSTRATE FOR THE TRANSFER OF A GALLIUM NITRID LAYER

Abstract

The present invention relates to a donor substrate for the transfer of a gallium nitride (GaN) layer, comprising a support substrate (10, 50) and a GaN layer extending over the support substrate, said GaN layer having: a doped region (30), referred to as the confinement region, containing dopants adapted to form complexes with hydrogen (H) atoms, said doped region (30) extending in a plane parallel to a principal surface of the support substrate (10), and a region (40), referred to as the active region, extending over the confinement region (30) on the side opposite the support substrate. Figure for the abstract: Fig. 4

Description

Title of the invention: DONOR SUBSTRATE FOR THE TRANSFER OF A GALLIUM NITRID LAYER FIELD OF INVENTION

[0001] The present invention relates to a donor substrate for the transfer of gallium nitride (GaN) layers. The invention also relates to a method for manufacturing such a donor substrate. STATE OF THE ART

[0002] Smart Cut™ technology enables the transfer of a layer from a donor substrate to a recipient substrate to form multilayer substrates, typically for the manufacture of electronic components. This process involves implanting atomic species into a donor substrate to create a zone of embrittlement at a predetermined depth, with the aim of detaching a thin layer delimited by said zone of embrittlement.

[0003] One objective of the transfer of the layer delimited by a weakening zone is to preserve the crystalline lattice of the transferred layer. The quality of this crystalline lattice is an important criterion for the manufacture of electronic components.

[0004] The atomic species create defects in the crystal lattice of the donor substrate, the set of defects forming the embrittlement zone. After the donor substrate is bonded to the recipient substrate, a heat treatment causes the donor substrate to fracture at the embrittlement zone, thus allowing the detachment of said thin layer bonded to the recipient substrate.

[0005] For the detachment of the thin film, it is important that the defects are distributed in the thickness of the substrate according to a regular distribution and that the area of ​​embrittlement extends substantially in a plane parallel to the main face of the donor substrate.

[0006] For the fabrication of certain components, particularly in optoelectronics, power electronics and radio frequency applications, gallium nitride (GaN) layers are used. The layer transfer and consequently the implantation of atomic species, typically hydrogen atoms, is preferably carried out in the (001) plane of the GaN crystal.

[0007] The defects created by the implantation of hydrogen atoms are generally vacancies propagating through the GaN substrate, particularly in the case of implantation in the (001) plane. A vacancy is an unoccupied atomic site in the crystal structure. Unlike the defects created by hydrogen implantation In other types of semiconductors, vacancies easily disperse towards the surface or into the interior of the GaN substrate. This makes it difficult to obtain a clean embrittlement zone.

[0008] In order to create a weakening zone enabling controlled fracture, it is currently necessary to implant high doses of atomic species due to the dispersion of defects. However, this implies long implantation times and significant energy consumption, which has a strong impact on the cost and environmental sustainability of the process. This makes the transfer of GaN layers by the Smart Cut™ type process incompatible with industrial-scale manufacturing.

[0009] Cherkashin et al. proposed confining the defects created by hydrogen atoms between two stacks of thin films of indium gallium nitride (InGaN) and GaN. The InGaN layers promote defect confinement due to the different lattice parameters of InGaN compared to GaN, resulting in compressive stress on the GaN crystal. This compressive stress has a detrimental effect on the crystalline quality of the GaN layers deposited on such a stack.

[0010] It is therefore desirable to find an alternative solution allowing the location of the embrittlement zone without exerting stress on the GaN crystal lattice. Description of the invention

[0011] An object of the invention is to make available a donor substrate allowing the transfer of a layer of GaN delimited by a zone of embrittlement created by the implantation of a dose of hydrogen atoms lower than the doses used in known processes, while ensuring a good quality of the crystalline lattice of the GaN layer.

[0012] To this end, the invention proposes a donor substrate for the transfer of a gallium nitride layer, comprising a support substrate and a GaN layer extending over the support substrate, said GaN layer having: • a doped region, called the confinement region, containing dopants adapted to form complexes with hydrogen atoms, said doped region extending in a plane parallel to a principal surface of the supporting substrate and • a region, called the active region, extending over the confinement region on the side opposite the supporting substrate.

[0013] Dopants make it possible to limit the propagation of hydrogen atoms and defects caused by their implantation, thus allowing the creation of a localized weakening zone in the donor substrate.

[0014] Preferably, the GaN layer comprises an alternating stack of a plurality of doped regions and active regions.

[0015] Advantageously, the dopants are magnesium, silicon or carbon atoms.

[0016] Advantageously, each active region has a thickness between 100 nm and 2 pm, preferably between 100 nm and 1 pm, preferably between 350 and 450 nm.

[0017] Preferably, each doped region has a thickness between 5 and 300 nm, preferably between 5 and 100 nm, and more preferably between 10 and 20 nm.

[0018] Each doped region can have a concentration of dopants between 1017 and 2-1020 atoms / cm3, preferably between 1018 and 1020 atoms / cm3.

[0019] The invention also relates to a method for manufacturing a donor substrate as described above, comprising providing a first support substrate, followed by the following steps:

[0020] (i) the formation of a GaN-doped region containing dopants suitable for form complexes with hydrogen atoms on the first supporting substrate, and

[0021] (ii) the formation of an active GaN region on the doped region.

[0022] Preferably, steps (i) and (ii) of formation of the doped region and the active region are carried out by epitaxial growth.

[0023] Advantageously, the doping of the doped region is carried out during epitaxial growth.

[0024] Advantageously, steps (i) and (ii) of formation of a doped region and an active region are repeated.

[0025] Preferably, the manufacturing process further includes, before the step of forming the doped region and the active region, the deposition of a buffer layer of GaN or the transfer of a seed layer of GaN onto the first support substrate.

[0026] In certain embodiments, the manufacturing process further comprises, after the formation of the doped region and the active region, the following steps:

[0027] (iii) the bonding of a free face of the GaN layer onto a second supporting substrate,

[0028] (iv) the removal of the first supporting substrate, so as to expose an opposite face of the GaN layer.

[0029] The invention also relates to a method for transferring an active region of GaN onto a receiving substrate, comprising the following steps: providing a donor substrate as described above, • the implantation of hydrogen in the doped region to form a zone of embrittlement, the dopants forming complexes with hydrogen atoms such that the defects generated by said implantation are confined within the doped region, • the bonding of the active region to the receiving substrate, • the detachment of the donor substrate along the weakening zone.

[0030] The dose of hydrogen atoms implanted in the doped region can be less than 1017, preferably less than 5-1016 atoms / cm2.

[0031] Preferably, the transfer method further includes a step of removing a remnant of the doped region disposed on the transferred active region after the detachment step, so as to expose the transferred active region.

[0032] In certain embodiments, the donor substrate comprises a plurality of doped regions and superimposed active regions and the embrittlement zone is formed in the doped region closest to the upper face of the donor substrate, and said method further comprises a step of removing a remnant of the doped region disposed on the donor substrate after the detachment step, so as to expose a second active region on the donor substrate. DESCRIPTION OF THE FIGURES

[0033] Other features and advantages of the invention will become apparent from the detailed description that follows, with reference to the accompanying drawings, in which:

[0034] Fig. 1 is a cross-sectional view of a donor substrate according to the invention.

[0035] Figure [Fig. 2] is a cross-sectional view of a supporting substrate according to a first mode of realization.

[0036] Fig. 3 is a cross-sectional view of a support substrate according to a second embodiment.

[0037] Figure 4 illustrates a donor substrate according to the invention comprising several doped regions and several superimposed active regions of GaN.

[0038] Fig. 5 illustrates a plurality of transfer stacks arranged on a first support substrate and intended to be transferred to a second support substrate.

[0039] Fig. 6A illustrates a first step of transferring the plurality of transfer stacks from Fig. 5 onto a second supporting substrate.

[0040] Fig. 6B illustrates a second step in the transfer of the plurality of transfer stacks from Fig. 5 onto a second supporting substrate.

[0041] Fig. 7A illustrates a first step in transferring a layer of GaN from a donor substrate according to the invention to a receiving substrate.

[0042] Fig. 7B illustrates the first step of transferring a GaN layer from a donor substrate according to the invention to a receiving substrate from a donor substrate comprising several transfer stacks.

[0043] Figure 8A illustrates a second step in the transfer of a GaN layer from a donor substrate according to the invention to a receiving substrate.

[0044] Fig. 8B illustrates the second step of transferring a GaN layer from a donor substrate according to the invention to a receiving substrate from a donor substrate comprising several transfer stacks.

[0045] Figure 9 illustrates a third step of transferring a GaN layer from a donor substrate according to the invention to a receiving substrate.

[0046] Fig. 1OA illustrates a fourth step of transferring a GaN layer from a donor substrate according to the invention to a recipient substrate.

[0047] Fig. 1OB illustrates the fourth step of transferring a GaN layer from a donor substrate according to the invention to a receiving substrate from a donor substrate comprising several transfer stacks.

[0048] Fig. 11 illustrates a receiving substrate onto which a layer of GaN has been transferred.

[0049] Fig. 12A illustrates a first polarity reversal step of a GaN layer transferred onto a receiving substrate.

[0050] Fig. 12B illustrates a second polarity reversal step of a GaN layer transferred onto a receiving substrate.

[0051] Fig. 13 illustrates a donor substrate comprising several transfer stacks prepared for a second transfer of a layer of GaN.

[0052] For reasons of readability of the figures, the illustrated elements are not necessarily represented to scale. DETAILED DESCRIPTION OF THE INVENTION

[0053] Figure 1 illustrates a donor substrate according to the invention. The donor substrate comprises, from its base to its surface, a support substrate 10 and a transfer stack 400 from which a layer of gallium nitride (GaN) can be transferred onto a receiving substrate.

[0054] The support substrate 10 is typically made of silicon (Si), silicon carbide (SiC), aluminum oxide (Al₂O₃), or GaN. Referring to [Fig. 2], the support substrate 10 may consist of a base substrate 11 and a buffer layer 12 extending over a front face of the base substrate 11. The base substrate 11 supports the buffer layer 12 and provides the mechanical strength of the assembly. By way of illustration and without limitation, the base substrate 11 may, for example, be made of Si, sapphire, SiC, polycrystalline AIN, or be a composite substrate comprising a stack of several of these materials.

[0055] The buffer layer 12 is made of aluminum nitride (AIN) or aluminum gallium nitride (AlGaN) and allows for consideration of lattice asymmetries and thermal expansion constraints of the donor substrate in order to ensure good crystalline quality during the deposition of the layers of the transfer stack 400. In an illustrative and non-limiting manner, the buffer layer may have a thickness between 100 nm and 1 pm, for example between 300 and 500 pm.

[0056] Alternatively, with reference to [Fig.3], the support substrate may consist of a base substrate 11 and a GaN seed layer 13 extending over a front face of the base substrate 11. The seed layer 13 may, for example, be transferred onto the base substrate 11 by a transfer process from another donor substrate.

[0057] In some cases, the substrate support 10 may consist of a central layer of polycrystalline AIN surrounded by several dielectric layers, and carry a layer such as a silicon layer (111) transferred onto its surface. Such substrates are, for example, manufactured using QST™ technology and marketed by Qromis.

[0058] In other embodiments (not shown), the support substrate is a bulk GaN substrate and does not include any buffer layer or additional seed layer. The support substrate may be any other substrate allowing the deposition of multiple GaN layers by epitaxial growth.

[0059] A GaN layer intended for transfer onto a receiving substrate is arranged on the surface of the donor substrate. To transfer this GaN layer onto the receiving substrate, it is necessary to create a weakening zone between the GaN layer and the substrate. To ensure proper localization of the weakening zone, it is created within a confinement region arranged between the substrate and the GaN layer to be transferred. Each GaN layer to be transferred and its associated confinement region together form a transfer stack.

[0060] With reference to [Fig. 1], the transfer stack 400 comprises at least one confinement region 30 of defects in the crystal lattice, and a GaN region 40 to be transferred.

[0061] The confinement region is made of GaN and extends between the support substrate and the GaN layer to be transferred. This confinement region has a thickness of between 5 and 300 nm, preferably between 5 and 100 nm, and more preferably between 10 and 20 nm. Such a thickness is suitable for creating a zone of embrittlement during the transfer of a GaN layer. The GaN in the confinement region is doped with dopants suitable for forming complexes with hydrogen atoms (H) upon implantation of said atoms in the donor substrate, typically with magnesium, silicon, and / or carbon dopants. In some embodiments, the dopants may be cadmium or calcium. These dopants readily bind to hydrogen atoms during implantation and can promote the aggregation of the atoms implanted in the confinement region.

[0062] The concentration of dopants is typically between 1017 and 2-1020 atoms / cm³, preferably between 10 and 10 atoms / cm³.

[0063] The GaN region to be transferred, referred to as the active region, typically has a thickness between 100 nm and 2 pm, preferably between 100 nm and 1 pm, for example between 350 and 450 nm. The active region 40 may be doped according to the intended application of the GaN layer after transfer and typically includes dopants different from those of the confinement region. In particular, the active region does not include any intentional doping designed to bind to hydrogen atoms. If residual doping capable of binding hydrogen atoms is present in the active region, said residual doping is considerably lower than the doping in the doped region 30, for example between 0.1% and 1% of the doping in the doped region.

[0064] Typically, with reference to [Fig. 4], a donor substrate according to the invention comprises a plurality of transfer stacks 400 superimposed on a single support substrate 10. The doped regions 30 and the active regions 40 are thus alternately superimposed on the front face of the support substrate 10. This superposition makes it possible to fabricate a single donor substrate by an epitaxial growth process in a single deposition chamber and to transfer, from this single donor substrate, a plurality of layers onto different recipient substrates intended for the fabrication of electronic components. This makes it possible to considerably increase the manufacturing efficiency of substrates for electronic applications compared to the use of donor substrates, each allowing the transfer of only one GaN layer.

[0065] Each transfer stack 400 comprises a containment region 30 and an active region 40.

[0066] The number of transfer stacks depends on the desired number of layers to be transferred and the maximum thickness of the donor substrate. The maximum thickness of the donor substrate will be chosen based on the size and material of the support substrate, particularly in terms of the crystal lattice and the coefficient of thermal expansion of the support substrate 10 and any buffer layer 12. For example, the total thickness of the transfer stacks can be limited to a value between 1.5 pm and a few hundred pm for a number of transfer stacks between 1 and 40, preferably between 1 and 30. Such a thickness makes it possible to take into account the constraints of the epitaxial growth manufacturing process and to obtain layers of good crystalline quality. Donor substrate fabrication

[0067] We will now describe a method for manufacturing a donor substrate as described above.

[0068] The process begins by providing a first support substrate 10, which can be silicon (Si), silicon carbide (SiC), aluminum oxide (Al₂O₃), or GaN. The first support substrate may include a buffer layer 12 or a seed layer 13 to facilitate the growth of single-crystal GaN on its surface. Referring to [Fig. 1], the epitaxial growth of a first doped region 30 is carried out by GaN epitaxy together with the chosen type(s) of dopant(s).

[0069] Subsequently, an active region of GaN 40 is deposited on the doped region 30 by epitaxy. During this step, the active region can be doped according to the intended applications of said layer.

[0070] The deposition steps can be repeated in order to deposit a plurality of superimposed transfer stacks 400 on the same substrate, each comprising a doped region 30 and an active region 40. This makes it possible to obtain, by a single process, a donor substrate suitable for the transfer of several layers of GaN onto several respective recipient substrates, making the process more efficient and therefore more economical.

[0071] The layers are typically deposited successively onto the substrate in a single epitaxial chamber to avoid transfer steps that would make the process longer and more expensive. This also prevents the introduction of contaminants into the deposition chamber and / or the substrate being manufactured.

[0072] Gallium nitride crystallizes in a crystalline structure exhibiting intrinsic polarity, which can be Ga-faced, terminated by gallium atoms, or N-faced, terminated by nitrogen atoms, depending on whether the growth direction is

[0001] (Ga polarity) or [000-1] (N polarity). The electrical and electrochemical properties of a GaN layer depend on its polarity on the substrate. Most GaN-based electronic components are manufactured with Ga polarity due to its advantages in terms of crystalline quality and electrical properties.

[0073] During epitaxial growth deposition, a Ga-face polarity is typically preferred due to the better crystalline quality that can be obtained in this polarity. During the transfer of a layer onto a receiving substrate, the GaN layer is inverted and therefore exhibits an N-face polarity on the receiving substrate. It is therefore necessary for most electronic components to perform a second transfer step to invert the layer's polarity a second time. Such a double transfer makes it possible to obtain a Ga-face polarity on the receiving substrate on which the electronic components will be fabricated.

[0074] In this case, with reference to [Fig. 4], one or more transfer stacks are deposited on the first support substrate 10 in the reverse order of that described above, to form a temporary substrate. Optionally, a demounting layer (not shown) may be deposited before the stacks are deposited. transfer. We begin, for example, with the deposition of an active region 40, which may include doping depending on the electronic application for which the GaN layer to be transferred is intended. A doped region 30 is deposited on the active region 40. The deposition of the transfer stacks 400 can be repeated one or more times.

[0075] Subsequently, with reference to [Fig. 6A], a second support substrate 50 is bonded to the front face of the temporary substrate 100. The second support substrate is, for example, made of silicon and may have a silicon oxide layer on its surface. In other embodiments, the second substrate may be made of another material such as polycrystalline aluminum nitride or polycrystalline silicon carbide. Typically, without limiting the invention, the second support substrate is bonded to a doped region 30. The second support substrate 50 may be made of Si, SiO2, AlN, Al2O3, or GaN, of Si bearing a surface layer of SiO2, or any other substrate suitable for receiving the transfer stacks 400. The first support substrate 10 can then be removed with reference to [Fig. 6B].Removal can be achieved by various techniques, for example by mechanical removal, grinding, by irradiation of the interface by a laser (LLO, acronym for the Anglo-Saxon term "Laser Lift-Off" for laser detachment), or by dismantling a demounting layer deposited on the first support substrate 10 before the deposition of the transfer stacks 400.

[0076] In any event, since the alternation of regions is symmetrical, one can start with a doped region or an active region for the production of a temporary substrate, and remove an unused region if necessary.

[0077] In an alternative embodiment, a temporary substrate is formed as described above by depositing one or more transfer stacks onto a support substrate, typically such that the GaN layers on the temporary substrate 100 exhibit Ga polarity, and without polarity reversal. Polarity reversal can then be achieved by transferring a single GaN layer onto a first receiving substrate and subsequently onto a second receiving substrate, as described below. Transfer of a layer onto a receiving substrate

[0078] The donor substrate is intended for the transfer of a GaN layer onto a receiving substrate, which is typically a polycrystalline silicon carbide, passivated polycrystalline aluminum nitride, or a substrate with a SiO2 surface layer, or silicon. Depending on the desired polarity of the GaN layer after transfer, a donor substrate fabricated by epitaxial growth of one or more transfer stacks on a single support substrate is chosen, or a donor substrate fabricated using a temporary substrate and a second support substrate as described above. In both cases, the donor substrate comprises a support substrate. and one or more transfer stacks. A layer of GaN to be transferred extends over the top face of the donor substrate.

[0079] Hereafter, reference number 10 will be used for the support substrate used in the process of transferring a layer onto a receiving substrate. This substrate can also be a second support substrate bonded to the transfer stacks in a polarity reversal step as described above and illustrated in Figures 6A and 6B.

[0080] To carry out a transfer of a layer of GaN, with reference to [Fig.7A] and [Fig.7B], an implantation of hydrogen atoms is implemented, so as to form a weakening zone 31 in the doped region 30. In the case of a plurality of transfer stacks on a donor substrate, as illustrated in [Fig.7B], the implantation is carried out in the doped region 30 closest to the front face of the donor substrate.

[0081] Implantation is performed with a maximum concentration c near the middle of the doped region 30 of GaN, at a depth p that is typically between 300 and 700 nm, for example 400 nm from the surface of the donor substrate, and can be deeper in the case of thick active regions. Generally, the implantation depth p corresponds to the thickness of the active region plus half the thickness of the doped region. The graph on the left side of [Fig. 7A] and [Fig. 7B] illustrates the concentration of the implanted species as a function of depth from the surface of the donor substrate. The peak width at concentration (FWHM) can, for example, be between 100 and 200 nm or more.

[0082] The implanted hydrogen atoms form complexes with the dopants in the doped region and therefore remain within the doped region 30. The dopants thus promote the agglomeration of vacancies in the crystal lattice formed due to the implantation of the hydrogen atoms. The subsequent precipitation of these vacancies in the form of pyramidal defects therefore also occurs within the doped region 30. The collection of pyramidal defects weakens the substrate in a specific area and can initiate substrate fracture along this weakened zone during thermal or mechanical treatment.

[0083] With reference to [Fig. 8A] and [Fig. 8B], the donor substrate is then bonded to a recipient substrate 60 to obtain a substrate in which GaN-based electronic components can be fabricated. The bonding can be achieved by direct contact, optionally preceded by surface activation of the donor substrate and / or the recipient substrate, for example, by cleaning and a chemical mechanical polishing (CMP) step, and / or surface activation by plasma or reactive ion etching (RIE). "). Bonding can also be achieved by hydrophilic or hydrophobic bonding and / or by means of one or more bonding layers which can be applied to the donor substrate and / or the recipient substrate, for example layers of SiO2, Si, tungsten or titanium.

[0084] The donor substrate is subsequently detached along the embrittlement zone 31, for example by heat treatment or by applying mechanical stress. Heat treatment is typically carried out at a temperature between 300°C and 400°C. With reference to [Fig. 9], the detachment of the donor substrate leads to the transfer of the active GaN region with a portion 32 of the doped region 30 onto the recipient substrate 60. With reference to [Fig. 1OA] and [Fig. 1OB], a second portion 33 of the doped region 30 remains on the donor substrate.

[0085] With reference to [Fig. 11], the portion 32 of the GaN-doped region is subsequently removed from the receiving substrate by a chemical and / or mechanical method. Preferably, the removal is carried out selectively, for example by wet etching, plasma etching, or chemical-mechanical polishing (CMP), in order to avoid degradation of the transferred GaN layer 40, which will be used to fabricate one or more electronic components. In some embodiments, reversing the polarity of the transferred layer 40 is desired, particularly when the polarity of the transfer stacks has not been reversed during the fabrication of the donor substrate as described above and illustrated in Figures 6A and 6B.

[0086] For example, when the polarity of the layer to be transferred onto the donor substrate is Ga polarity, the GaN 40 layer exhibits N polarity after transfer to the receiving substrate 60. In this case, the receiving substrate 60 is a first receiving substrate and is used only temporarily. Optionally, the first receiving substrate 60 may include a demounting layer (not shown) on its surface. During the transfer steps described above and illustrated in Figures 7A to 11, the GaN 40 layer is transferred onto the first receiving substrate 60. When the first receiving substrate 60 includes a demounting layer, said demounting layer is arranged at the interface between the first receiving substrate 60 and the transferred GaN 40 layer.

[0087] In a subsequent step, the GaN 40 layer arranged on the first receiving substrate 60 is glued onto a second receiving substrate 61 as illustrated in [Fig.12A].

[0088] With reference to [Fig. 12B], the first receiving substrate 60 is then removed, for example by mechanical removal, grinding, an LLO process, or by dismantling the removal layer arranged at the interface between the GaN layer 40 and the first receiving substrate 60.

[0089] After these steps, the GaN layer 40 is arranged on the second receiving substrate 61 in a reversed position with respect to its arrangement on the first receiving substrate 60. Thus, the polarity of the transferred GaN layer 40 is also reversed, typically to a Ga polarity.

[0090] After transferring the GaN layer onto the second receiving substrate 61, any residues on its surface can be removed. Any residue from the transfer stacks of the first receiving substrate 60 can also be removed so that said first receiving substrate 60 can be reused for a new transfer of a GaN layer onto one of the other receiving substrates intended for the manufacture of electronic components.

[0091] After the transfer steps, a finishing treatment of the transferred layer can be implemented, so as to cure the defects related to the implantation and to smooth the free surface of said layer.

[0092] When the donor substrate comprises other transfer stacks 400, as referred to in [Fig. 1OB] and [Fig. 13], the second portion 33 of the doped region is also removed, for example by wet etching, plasma etching, or chemical-mechanical polishing (CMP), in order to expose a new active region 40A for transfer. A surface treatment can be applied to prepare the donor substrate for the transfer of a new GaN 40A region onto another receiving substrate. The transfer steps can then be repeated to transfer each active region to be transferred onto a respective receiving substrate. REFERENCES

[0093] N. Cherkashin et al., “Confinement of vacancies during annealing of H implanted GaN sandwiched between two {InGaN / GaN} superlattices”, Appl. Phys. Lett 101, 023105 (2012).

Claims

Demands

1. Donor substrate for the transfer of a gallium nitride (GaN) layer, comprising a support substrate (10, 50) and a GaN layer extending over the support substrate, said GaN layer having: • a doped region (30), called the confinement region, containing dopants adapted to form complexes with hydrogen (H) atoms, said doped region (30) extending in a plane parallel to a principal surface of the support substrate (10) and • a region (40), called the active region, extending over the confinement region (30) on the side opposite the support substrate (10).

2. Donor substrate according to claim 1, wherein the GaN layer comprises an alternating stacking of a plurality of doped regions (30) and active regions (40).

3. Donor substrate according to claim 1 or claim 2, wherein the dopants are magnesium (Mg), silicon (Si) or carbon (C) atoms.

4. Donor substrate according to any one of the preceding claims, wherein each active region (40) has a thickness between 100 nm and 2 pm, preferably between 100 nm and 1 pm, preferably between 350 and 450 nm.

5. Donor substrate according to any one of the preceding claims, wherein each doped region (30) has a thickness of between 5 and 300 nm, preferably between 5 and 100 nm, and more preferably between 10 and 20 nm.

6. Donor substrate according to any one of the preceding claims, wherein each doped region (30) has a dopant concentration of between 1017 and 2-1020 atoms / cm3, preferably between 10 and 10 atoms / cm3.

7. A method for manufacturing a donor substrate according to any one of claims 1 to 6, comprising providing a first support substrate (10), followed by the following steps: (i) the formation of a doped region (30) of GaN containing dopants suitable for forming complexes with hydrogen atoms on the first support substrate (10), and (ii) the formation of an active region (40) of GaN on the doped region (30).

8. A method for manufacturing a donor substrate according to claim 7, wherein steps (i) and (ii) of formation of the doped region (30) and the active region (40) are carried out by epitaxial growth.

9. A method for manufacturing a donor substrate according to claim 8, wherein the doping of the doped region (30) is carried out during epitaxial growth.

10. A method for manufacturing a donor substrate according to any one of claims 7 to 9, wherein the steps (i) and (ii) of forming a doped region (30) and an active region (40) are repeated.

11. A method for manufacturing a donor substrate according to any one of claims 7 to 10, further comprising, before the step of forming the doped region (30) and the active region (40), the deposition of a buffer layer (12) of GaN or the transfer of a seed layer (11) of GaN onto the first support substrate (10).

12. A method for manufacturing a donor substrate according to any one of claims 7 to 11, further comprising, after the formation of the doped region (30) and the active region (40), the following steps: (iii) bonding a free face of the GaN layer to a second support substrate (50), (iv) removing the first support substrate (10), so as to expose an opposite face of the GaN layer.

13. A method for transferring an active region of GaN onto a receiving substrate, comprising the following steps: • providing a donor substrate according to any one of claims 1 to 6, • implanting hydrogen in the doped region (30) to form a weakening zone (31), the dopants forming complexes with hydrogen atoms (H) such that the defects generated by said implantation are confined within the doped region (30), • the bonding of the active region (40) to the receiving substrate (60), • the detachment of the donor substrate along the weakening zone (31).

14. Transfer method according to claim 13, wherein the dose of hydrogen atoms implanted in the doped region is less than 1017, preferably less than 5-1016 atoms / cm2.

15. A transfer method according to claim 13 or claim 14, further comprising a step of removing a remnant (32) of the doped region (30) disposed on the active region (40) transferred after the detachment step, so as to expose the transferred active region (40).

16. A transfer method according to any one of claims 13 to 15, wherein the donor substrate comprises a plurality of superimposed doped regions (30) and active regions (40), and the embrittlement zone (31) is formed in the doped region (30) nearest to the upper face of the donor substrate, said method further comprising a step of removing a remnant (33) of the doped region disposed on the donor substrate after the detachment step, so as to expose a second active region (40a) on the donor substrate.

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