Method for manufacturing donor substrate for use in piezoelectric thin film transfer method

Abstract

The invention relates to a method for producing a donor substrate for transferring a piezoelectric film onto a final support substrate, comprising the following steps: a) providing a bulk processing substrate (102), in particular a silicon-based bulk processing substrate; c) providing a piezoelectric material (114, 142) over the bulk processing substrate (102), characterized in that the method further comprises, prior to the step c) of providing the piezoelectric material (114, 142), a step b) of implanting (106) the bulk processing substrate (102) to form a brittle region (104) in the bulk processing substrate (102). The invention also relates to a donor substrate (100, 138, 148), in particular a donor substrate obtained by the production method according to the invention, and to a method for transferring a piezoelectric thin film using a donor substrate (100, 138, 148) according to the invention.

Description

[0001] The present invention relates to a method for manufacturing a donor substrate used in a piezoelectric thin film transfer method and a donor substrate obtained by such a method.

[0002] Piezoelectric-on-insulator (POI) substrates include a thin film of piezoelectric material on a substrate. To manufacture such POI substrates, the method used involves transferring the piezoelectric thin film from a thick substrate of piezoelectric material to a final supporting substrate.

[0003] To achieve this, a donor substrate is first used, in which a bulk substrate of piezoelectric material is bonded to a handling substrate by adhesive bonding (particularly using a polymer film) or molecular bonding. Next, a thinning step of the piezoelectric bulk substrate is performed on the donor substrate before bonding to the supporting substrate to form a thinner piezoelectric film. Finally, the piezoelectric film is mechanically or thermally transferred to the final substrate via the fracture zone previously formed in the thinned piezoelectric film. The donor substrate is introduced into the method to limit the negative impact of the difference in thermal expansion coefficients between the piezoelectric material and the final POI supporting substrate. A thermal treatment is used to enhance the bonding interface between different substrates and transfer the film. Examples of this method are described in WO 2019 / 186032 A1 or WO 2019 / 002080A1.

[0004] After the transfer of the plurality of piezoelectric films to the final support substrate, the remaining part of the donor substrate is discarded, since it can no longer be used in any manufacturing method due to the thickness limit, below which the transfer of the piezoelectric films to the final substrate is no longer feasible. It is therefore necessary to manufacture a new donor substrate using a new handle substrate in order to be able to perform the piezoelectric film transfer method for manufacturing the POI substrate again.

[0005] Therefore, since each method of manufacturing a donor substrate for transferring a piezoelectric thin film requires the use of a new, newly manufactured handle substrate, such methods have high costs.

[0006] An object of the present invention is to overcome the aforementioned disadvantages and in particular to provide a method for manufacturing a donor substrate which makes it possible to reduce the costs of the manufacturing method and therefore also the costs of the piezoelectric film transfer method using such a donor substrate.

[0007] The subject matter of the present invention is achieved through a piezoelectric thin film transfer method, which comprises: a) providing a donor substrate, which comprises a bulk handling substrate (especially a silicon-based bulk handling substrate) having a brittle zone and a piezoelectric material, which is above the bulk handling substrate; b) forming the brittle zone inside the piezoelectric material of the donor substrate, especially forming the brittle zone by ion implantation; c) providing a final supporting substrate, especially a silicon-based final supporting substrate; d) attaching the donor substrate to the final substrate to obtain a donor substrate / final supporting substrate assembly; and e) breaking the piezoelectric material along the brittle zone to separate the piezoelectric film from the remaining part of the donor substrate.

[0008] According to one embodiment, step e) of fracturing the piezoelectric material along the embrittlement zone may be performed at a temperature lower than the temperature used to perform fracturing at the embrittlement zone of the bulk handle substrate of the donor substrate.

[0009] According to one embodiment, steps a) to e) may be repeated at least once and, starting from the second iteration, step a) may be performed with the remainder of the donor substrate obtained at the end of step e) of the previous iteration.

[0010] In one embodiment, steps a) to e) may be repeated as long as the thickness of the piezoelectric film of the remaining portion of the donor substrate obtained in step e) is greater than 5 μm.

[0011] In one embodiment, step f) of breaking the remaining portion of the donor substrate at the embrittled region of the bulk handle substrate may be performed after step e).

[0012] According to one embodiment, when the piezoelectric film thickness of the donor substrate remainder obtained in step e) is equal to or less than 5 μm, a breaking step f) may be performed to obtain a bulk handle substrate remainder.

[0013] In one embodiment, step f) of breaking the remaining portion of the donor substrate along the embrittled region of the bulk handle substrate may be performed by heat treatment.

[0014] According to one embodiment, the donor substrate provided in step a) can be obtained by implementing a method for manufacturing a donor substrate for transferring a piezoelectric film onto a final support substrate. The method for manufacturing a donor substrate for transferring a piezoelectric film onto a final support substrate may include the following steps: a) providing a bulk handle substrate, in particular a silicon-based bulk handle substrate; c) providing a piezoelectric material above the bulk handle substrate; and also including a step b) of implanting the bulk handle substrate to provide an embrittlement zone in the bulk handle substrate before the step of providing the piezoelectric material.

[0015] According to one embodiment, step a) of providing a bulk handle substrate (102) may include using a remaining portion of the bulk handle substrate obtained after step f) of the previously described piezoelectric thin film transfer method.

[0016] In one embodiment, step g) for treating the surface of the remaining portion of the bulk handling substrate may be performed after step f) of the above-described piezoelectric thin film transfer method.

[0017] According to one embodiment, the step b) of implanting the bulk process substrate may be performed with less than 6×10 16 cm -2 , especially below 5×10 16 cm -2 The implantation is performed with an implantation dose of, even more particularly, an implantation of hydrogen H, helium He or a co-implantation of hydrogen H and helium H.

[0018] According to one embodiment, step c1) of providing an intermediate film between the bulk handle substrate and the piezoelectric material may be performed before said step c) of providing the piezoelectric material on top of the bulk handle substrate.

[0019] According to one embodiment, the step c) of providing a piezoelectric material over a bulk handle substrate may comprise providing a bulk substrate based on a piezoelectric material.

[0020] According to one embodiment, said step c) of providing the piezoelectric material above the bulk handle substrate may further comprise a step of assembling the bulk handle substrate with the bulk substrate based on the piezoelectric material, in particular by molecular bonding.

[0021] According to one embodiment, step d) of thinning the piezoelectric material may be performed, in particular by grinding, more particularly during said method for manufacturing a donor substrate for transferring the piezoelectric film to a final supporting substrate.

[0022] According to one embodiment, said step d) of thinning the piezoelectric material may be performed to obtain a film of piezoelectric material having a thickness of 30 μm or less, in particular 20 μm or less.

[0023] According to one embodiment, said step c) of providing a piezoelectric material over the bulk handle substrate may be performed by epitaxially depositing a film based on the piezoelectric material on the bulk handle substrate.

[0024] According to one embodiment, the epitaxial deposition step may be performed at a temperature below 950°C, in particular below 900°C.

[0025] According to one embodiment, the donor substrate provided in step a) of the transfer method may be characterized in that the embrittled zone is located at a depth t of 500 nm in the bulk processing substrate, in particular at a depth t of 300 nm in the bulk processing substrate, and even more in particular at a depth t of less than 300 nm in the bulk processing substrate.

[0026] According to one embodiment, the donor substrate provided in step a) of the transfer method may be characterized in that the bulk handle substrate is a silicon carbide SiC substrate and the piezoelectric material is gallium nitride GaN.

[0027] The subject matter of the present invention can also be achieved by a method for manufacturing a donor substrate for transferring a piezoelectric film to a final supporting substrate, the method comprising the following steps: a) providing a bulk handling substrate, in particular a silicon-based bulk handling substrate; c) providing a piezoelectric material above the bulk handling substrate; characterized in that the method also includes a step b) of injecting the bulk handling substrate to provide a brittle zone in the bulk handling substrate before the step c) of providing the piezoelectric material.

[0028] Thus, a donor substrate manufactured by a method according to the invention can be fractured at a bulk handle substrate in a subsequent step. Fracture at an embrittled region of the bulk handle substrate of the donor substrate produces a bulk handle substrate remainder that can be used again in a subsequent method. In this way, costs associated with manufacturing a bulk handle substrate can be reduced by reusing or recycling portions of the bulk handle substrate.

[0029] According to one embodiment, step b) of implanting the bulk handle substrate may be performed with less than 6×10 16 cm -2 , especially below 5×10 16 cm -2 The implantation is performed with an implantation dose of, even more particularly, an implantation of hydrogen H, helium He or a co-implantation of hydrogen and helium H / He.

[0030] In this way, the embrittled zone in the bulk handle substrate is localized at a depth of less than 500 nm, in particular 300 nm, in the bulk handle substrate. This depth makes it possible to produce a thin film of the bulk handle substrate to be removed in a corresponding breaking step. In this way, the remaining part of the bulk handle substrate has a thickness that can still be reused in a subsequent method.

[0031] According to one embodiment, step c1) of providing an intermediate film between the bulk handle substrate and the piezoelectric material may be performed before step c).

[0032] Thus, the assembly between the bulk handling substrate and the piezoelectric material can be improved by the presence of the intermediate film. Furthermore, the intermediate film simplifies the formation of the assembled structure.

[0033] According to one embodiment, step c) of providing the piezoelectric material over the bulk handle substrate may comprise providing a bulk substrate based on the piezoelectric material.

[0034] The method according to the present invention can use a variety of piezoelectric materials, which play a major role in devices utilizing the piezoelectric effect. For example, lithium tantalate (LTO), lithium niobate (LNO), aluminum nitride (AlN), lead zirconate titanate (PZT), lanthanum gallium silicate (LGS) or lanthanum gallium tantalate (LGT) can be used.

[0035] According to one embodiment, step c) may also comprise a step of assembling the bulk handle substrate with the bulk substrate based on piezoelectric material, in particular by molecular bonding.

[0036] In this way, the assembly step enables a large number of different materials to be combined. Furthermore, the interface between the bulk handle substrate and the piezoelectric material is a stable assembly interface.

[0037] In one embodiment, step d) of thinning the piezoelectric material may be performed, in particular by grinding.

[0038] In this way, a piezoelectric film of desired thickness can be obtained from a thick piezoelectric substrate, and the donor substrate produced using the method of the present invention can be used to transfer the piezoelectric thin film to a supporting substrate to obtain a piezoelectric-on-insulator (POI) substrate with desired properties.

[0039] According to one embodiment, the thinning step d) may be performed to obtain a piezoelectric material having a thickness of 30 μm or less, in particular 20 μm or less.

[0040] The donor substrate thus produced by the method according to the present invention can be used as a donor substrate in a subsequent film transfer method for transferring a thin film of piezoelectric material to a final supporting substrate to form a piezoelectric on insulator (POI) substrate. In the method for manufacturing a POI substrate, the piezoelectric material and the final supporting substrate material have very different thermal expansion coefficients, resulting in significant deformation of the assembly. In such a method, due to the use of a donor substrate, a thick piezoelectric substrate is maintained between the processing substrate and the supporting substrate. The choice of material and thickness for the processing substrate and the final supporting substrate reduces the influence of the thermal expansion coefficient and thus minimizes the deformation of the assembly when a heat treatment is applied during the method for manufacturing a piezoelectric on insulator (POI) substrate. For example, the difference in thermal expansion coefficient between the processing substrate material and the final supporting substrate material is less than or equal to 5%, preferably equal to or close to 0%.

[0041] According to one embodiment, step c) of providing a piezoelectric material may be performed by epitaxially depositing a film based on a piezoelectric material.

[0042] In this way, the method enables obtaining in a controlled manner a film of piezoelectric material having a desired predetermined thickness and a quality suitable for SAW devices. For example, a film of gallium nitride GaN can be obtained, which is an interesting piezoelectric material for the manufacture of POI substrates.

[0043] According to one embodiment, the epitaxial deposition step may be performed at a temperature below 950°C, in particular below 900°C.

[0044] In this way, a high quality thick film of piezoelectric material can be obtained for later use in a SAW device.For example, the bulk handle substrate can be a silicon carbide SiC substrate and the piezoelectric material can be a gallium nitride GaN film.

[0045] The subject matter of the present invention can also be realized by a donor substrate, in particular a donor substrate obtained by the above method, which donor substrate comprises a bulk handling substrate, in particular a silicon-based bulk handling substrate; a piezoelectric material located above the bulk handling substrate; characterized in that the bulk handling substrate comprises a brittle zone.

[0046] Such donor substrates, particularly those fabricated using the methods described herein, can be used to transfer piezoelectric thin films to a support substrate to produce a piezoelectric-on-insulator (POI) substrate. Furthermore, once the piezoelectric thin film transfer method has been completed, the presence of the embrittlement zone in the bulk handle substrate enables a portion of the donor substrate to be recycled by breaking the donor substrate at the embrittlement zone. Breaking along the embrittlement zone of the handle substrate can be achieved by thermal or mechanical treatment.

[0047] According to one embodiment, the embrittled zone in the bulk handle substrate may be located at a depth t of 500 nm in the bulk handle substrate, particularly at a depth t of 300 nm in the bulk handle substrate, and even more particularly at a depth t of less than 300 nm in the bulk handle substrate.

[0048] According to one embodiment, the bulk handle substrate may be a silicon carbide SiC substrate, and the piezoelectric material may be a gallium nitride GaN film.

[0049] This combination of materials is of great interest for its subsequent use in power devices with addressing voltages of 1200 V or higher, or in radio frequency (RF) devices or optoelectronic devices such as micro-LEDs.

[0050] The subject matter of the present invention can also be implemented by a piezoelectric thin film transfer method, which comprises: a) providing a donor substrate, which comprises a block-shaped processing substrate having a brittle zone as described above or obtained by implementing a manufacturing method as described above; b) forming a brittle zone inside the piezoelectric material of the donor substrate, in particular forming the brittle zone by ion implantation; c) providing a final supporting substrate, in particular a final supporting substrate based on silicon; d) attaching the donor substrate to the final supporting substrate to obtain a donor substrate / final supporting substrate assembly; and e) breaking the piezoelectric material along the brittle zone to separate the piezoelectric film from the remaining part of the donor substrate.

[0051] In a method for manufacturing a POI substrate, the piezoelectric material and the support substrate material have very different thermal expansion coefficients, resulting in significant deformations of the assembly. In such a method, due to the use of a donor substrate, a thick piezoelectric substrate is held between a handling substrate and a final support substrate. The choice of materials and thicknesses for the handling substrate and the final support substrate makes it possible to ensure a certain symmetry of the thermal expansion coefficients and thus minimize deformations of the assembly when a heat treatment is applied during the method for manufacturing a piezoelectric-on-insulator (POI) substrate. For example, the difference in thermal expansion coefficient between the handling substrate material and the final support substrate material is less than or equal to 5%, preferably equal to or close to 0%.

[0052] According to one embodiment, step e) of fracturing the piezoelectric material along the embrittlement zone may be performed at a temperature lower than the temperature used to perform fracturing at the embrittlement zone of the bulk handle substrate of the donor substrate.

[0053] Therefore, only fractures at the embrittled zone of the piezoelectric material are performed during this step of the method.The energy input required to form fractures in the embrittled zone of the bulk handle substrate is insufficient, since the fractures are formed at a lower temperature than the required energy input.

[0054] According to one embodiment, steps a) to e) may be repeated at least once and, starting from the second iteration, step a) is performed with the remainder of the donor substrate obtained at the end of step e) of the previous iteration.

[0055] In this way, the donor substrate remainder can be recycled and even reused several times. This reduces the cost of the method, since multiple POI substrates can be produced from a single donor substrate.

[0056] In one embodiment, steps a) to e) may be repeated as long as the thickness of the piezoelectric film of the remaining portion of the donor substrate obtained in step e) is greater than 5 μm.

[0057] Therefore, as long as the piezoelectric film remaining on the remaining part of the donor substrate has sufficient thickness to transfer the piezoelectric film to the final support substrate, the remaining part of the donor substrate can be recycled and reused. This reduces the cost of the method because multiple POI substrates can be produced from a single donor substrate.

[0058] In one embodiment, step f) of breaking the remaining portion of the donor substrate at the embrittled region of the bulk handle substrate may be performed after step e).

[0059] In this way, a bulk handle substrate remainder having a free upper surface can be obtained. This bulk handle substrate remainder can be reused to manufacture a new donor substrate as described above.

[0060] According to one embodiment, when the piezoelectric film thickness of the remaining portion of the donor substrate obtained in step e) is less than or equal to 5 μm, step f) of breaking the remaining portion of the donor substrate at the brittle area of ​​the bulk handling substrate can be performed to obtain the remaining portion of the bulk handling substrate.

[0061] The step of breaking the remaining portion of the donor substrate separates the remaining piezoelectric film, the intermediate film and a portion of the bulk handle substrate having a thickness of 5 μm or less. In this way, a bulk handle substrate remaining portion is obtained, which has a free top surface that can be reused to manufacture a new donor substrate as described above.

[0062] In one embodiment, step f) of breaking the remaining portion of the donor substrate along the embrittled region of the bulk handle substrate may be performed by heat treatment.

[0063] A large amount of heat input is required to form fractures in the bulk handle substrate. This means that fractures of the bulk handle substrate at the embrittled region do not occur during other heat treatments previously performed in the piezoelectric thin film transfer process.

[0064] According to one embodiment, step a) of providing a bulk handle substrate of the method for manufacturing a donor substrate according to the invention may comprise using a bulk handle substrate remainder obtained after step f) of the above-described transfer method.

[0065] In this way, a portion of the bulk handle substrate can be recycled and reused after having been used in the transfer method. This reduces the costs associated with the production of bulk handle substrates for manufacturing donor substrates for piezoelectric thin film transfer, and therefore reduces the costs associated with the production of POI substrates.

[0066] In one embodiment, step g) for treating the free surface of the remaining portion of the bulk process substrate may be performed after step f) of the above-described transfer method.

[0067] In this way, the free surface of the remaining bulk handle substrate is free of particles and the bulk handle substrate remainder can be reused as a bulk handle substrate to manufacture a donor substrate. For example, process step g) is a CMP type cleaning step or a cleaning step using a cleaning spray.

[0068] The invention and its advantages will be explained in more detail by means of preferred embodiments and with particular reference to the following drawings, in which reference characters identify features of the invention.

[0069] Figure 1a A method for manufacturing a donor substrate according to a first embodiment of the present invention is schematically shown.

[0070] Figure 1b A method for producing a donor substrate according to a variant of the first embodiment of the invention is schematically shown.

[0071] Figure 2 A method for manufacturing a donor substrate according to a second embodiment of the present invention is schematically shown.

[0072] Figure 3a Steps a) to d) of a method for transferring a piezoelectric thin film according to a third embodiment of the present invention are schematically shown.

[0073] Figure 3b Schematically shows Figure 3a Steps e) and f) of the method for transferring a piezoelectric film according to the third embodiment of the present invention are shown.

[0074] Figure 3c A diagram showing a method for transferring a piezoelectric film according to a third embodiment of the present invention.

[0075] Figure 3d A method for transferring a piezoelectric film according to a variant of the third embodiment of the present invention is schematically shown.

[0076] Figure 4a A method for transferring a piezoelectric thin film according to a fourth embodiment of the present invention is schematically shown.

[0077] Figure 4b A method for manufacturing a donor substrate according to a fifth embodiment of the present invention is schematically shown.

[0078] The invention is described in more detail below using advantageous embodiments in an exemplary manner and with reference to the accompanying drawings. The described embodiments are only possible configurations, and it should be remembered that when implementing the invention, the various features described above may be provided independently of each other or may be omitted altogether.

[0079] Figure 1aA method for manufacturing a donor substrate according to a first embodiment of the present invention is depicted.

[0080] The method for manufacturing a donor substrate 100 starts with step a) of providing a bulk handle substrate 102. A bulk substrate is a substrate based on a single material, typically with a thickness between 300 μm and 800 μm.

[0081] The bulk handling substrate 102 is advantageously made of a material having a thermal expansion coefficient close to that of the material of the final support substrate to which the piezoelectric film will be transferred. "Close to" means that the difference in thermal expansion coefficient between the handling substrate material 102 and the final support substrate material is less than or equal to 5%, preferably equal to or close to 0%.

[0082] The bulk handle substrate 102 may be a silicon-based substrate. In one embodiment, the bulk handle substrate 102 may also be based on sapphire (Al2O3), aluminum nitride (AlN), silicon carbide (SiC), or gallium arsenide (GaAs). The bulk handle substrate 102 may be a crystalline substrate or a polycrystalline substrate.

[0083] According to the invention, step b) consists in forming an embrittled zone 104 in the bulk handle substrate 102. The formation of the embrittled zone 104 is achieved by implanting (106) atomic or ionic species into the bulk handle substrate 102 in step b). The atomic or ionic implantation 106 is performed on a free surface 108 of the bulk handle substrate 102. The atomic or ionic implantation 106 can be performed in such a way that the embrittled zone 104 is located inside the bulk handle substrate 102 at a depth t from the free surface 108 and separates the film 110 from the remaining part 112 of the bulk handle substrate 102. The atomic or ionic species are implanted at a given depth t of the bulk handle substrate 102, which determines the thickness t of the film 110. The thickness t is about 300 nm, in particular less than 300 nm.

[0084] The ion implantation 106 may be hydrogen H+ ion implantation or helium He2+ ion implantation, or hydrogen H and helium He ion co-implantation. The implantation dose of the ion species is less than 6×10 16 cm -2 In particular, for silicon substrates, the implantation dose is 4×10 16 cm -2 and 6×10 16 cm -2 between.

[0085] In one embodiment, a surface treatment step on the free surface 108 of the bulk handle substrate 102 may be performed prior to the implantation 106 of the bulk handle substrate 102. For example, a cleaning process of the RCA type.

[0086] In step c), a piezoelectric material 114 is provided over the bulk handle substrate 102 .

[0087] This is preferably a bulk substrate 116 formed of a single piezoelectric material 114, with a thickness t1 of typically about at least 300 μm, preferably between 300 μm and 800 μm.

[0088] The piezoelectric material 114 may be, for example, lithium tantalate (LTO), lithium niobate (LNO), aluminum nitride (AlN), lead zirconate titanate (PZT), lanthanum gallium silicate (LGS), or lanthanum gallium tantalate (LGT).

[0089] According to the present invention, a step c1) of providing at least one intermediate film 118 between the bulk handle substrate 102 and the piezoelectric material 114 is performed before step c) so that the intermediate film 118 is sandwiched between the bulk handle substrate 102 and the piezoelectric material 114 .

[0090] The intermediate film 118 may be disposed on the bulk handle substrate 102, and in particular, on the free surface 108 of the bulk handle substrate 102. The intermediate film 118 may be deposited directly on the free surface 108 of the bulk handle substrate 102. The intermediate film 118 may be formed on the free surface 108 of the bulk handle substrate 102 by spin coating or by a thermal or plasma assisted growth technique such as plasma enhanced chemical vapor deposition (PECVD) or physical vapor deposition (PVD).

[0091] Prior to forming the intermediate film 118 , one or more steps of cleaning, brushing or polishing the surface 108 of the bulk handle substrate 102 may be performed to remove the presence of particles and dust, thereby obtaining a cleaner free surface 108 and a better quality intermediate film 118 .

[0092] The intermediate film 118 formed on the bulk support substrate 102 may be a dielectric film, such as a film based on silicon oxide SiOx or silicon nitride Si3N4, or a combination of nitride and silicon oxide SiOxNy, or a film based on tantalum oxide Ta2O5, aluminum oxide Al2O3, hafnium oxide HfO2, and zirconium oxide ZrO2. Depending on the bonding technology used, the intermediate film 118 formed on the bulk support substrate 102 may also be a film of amorphous silicon or carbon or metal.

[0093] The intermediate film 118 has a thickness between 2 nm and 1000 nm.

[0094] In one variant, the intermediate film 118 formed on the bulk handling substrate 102 may be a photopolymerizable polymer film, in particular a polymer film based on a thiol-ene resin. The polymer film 118 used in the present invention may be, for example, a film sold by NORLAND PRODUCTS under the name "NOA61". In this case, the thickness of the polymer film 118 is preferably between 1 μm and 10 μm.

[0095] The polymer film 118 alone is able to adhere well to another film or substrate. In fact, after the assembly step of the donor substrate manufacturing method, a step of treating the polymer film 118 can be performed to obtain a cross-linked polymer film for bonding the handling substrate 102 to the piezoelectric material 114. The polymer film 118 can be cross-linked using heat, pressure, a change in pH or irradiation with a light flux 118 (preferably a laser). The light radiation 118 or light flux is preferably ultraviolet (UV) radiation, which preferably has a wavelength between 320 nm and 365 nm.

[0096] Thus, during the assembly step included in step c), the piezoelectric material 114 is assembled with the bulk handle substrate 102 to form a heterostructure 124 by bringing the intermediate film 118 into contact with the piezoelectric material 114. Thus, an assembly interface 126 is located between the piezoelectric material 114 and the intermediate film 118 of the handle substrate 102.

[0097] According to the invention, after the assembly step of step c), a step d) of thinning the piezoelectric material 114 is performed. The thinning is performed by grinding or by chemical etching of the piezoelectric material 114 to reduce the thickness t1 of the piezoelectric material 114, thereby obtaining a piezoelectric film 128 having a thickness t2 of about 20 μm or even between 5 μm and 20 μm.

[0098] Thus, at the end of step d) of the method, a bulk handling substrate / piezoelectric material assembly 100 (also referred to as donor substrate 100) is achieved, which assembly comprises a piezoelectric film 128 with a thickness of 20 μm or between 5 μm and 20 μm on a bulk handling substrate 102, the bulk handling substrate comprising a brittle zone 104, wherein the assembly interface 126 is realized by an intermediate film 118 sandwiched between the bulk handling substrate 102 and the film 128 of piezoelectric material 114.

[0099] In a variant, the intermediate film 118 may be disposed on the piezoelectric material 114 instead of on the bulk handling substrate 102 , in particular on the free surface 122 of the piezoelectric material 114 .

[0100] In another embodiment, the piezoelectric material 114 may be directly supplied onto the bulk handle substrate 102 without an intermediate film 118 therebetween.

[0101] Figure 1b A variation of the first embodiment of the invention is shown, in which the step c1) of providing the intermediate film 118 differs from the first embodiment. The intermediate film 118 is deposited on the bulk handling substrate 102 and on the piezoelectric material 114. All other steps a), b), c) and d) are the same as in the first embodiment. All features that are the same as in the first embodiment and use the same reference numerals as above will not be described again, but reference will be made to their above detailed description.

[0102] In step c1), the intermediate film 132 is arranged on the piezoelectric material 114, and the intermediate film 134 is arranged on the bulk handling substrate 102. Then, an assembly 136 of the handling substrate 102 and the piezoelectric material 114 is performed at the interface between the two intermediate films 132, 134. In particular, the intermediate films 132, 134 are based on dielectric materials, and the interface 130 is made of oxide-oxide bonds, in particular Si-O-Si bonds, which enable stable molecular force bonding.

[0103] In another embodiment, the intermediate films 132, 134 disposed on the piezoelectric material 114 and on the bulk handling substrate 102 are composed of different dielectric materials. For example, the intermediate film 132 disposed on the bulk handling substrate 102 is a silicon nitride Si3N4 film, and the intermediate film 134 disposed on the piezoelectric material 114 is a silicon oxynitride SiON film. The bulk handling substrate 102 is then bonded to the piezoelectric material 114 at the interface 130 between the two Si3N4-SiON dielectric films, which also provides a stable bond.

[0104] Thus, after step d) of the method, a donor substrate 138 is obtained, which comprises a piezoelectric film 128 with a thickness t2 of 20 μm or between 5 μm and 20 μm on a bulk handling substrate 102, the bulk handling substrate comprising an embrittlement zone 104, wherein the assembly interface 130 is made of two intermediate films based on different materials 132, 134.

[0105] Figure 2 A second embodiment of the invention of the method for manufacturing a donor substrate is shown. In this second embodiment, the step c1) of providing the intermediate film and the step c) of providing the piezoelectric material are different from those described in the first embodiment of the manufacturing method. Steps a) and b) are the same as those described in the first embodiment of the manufacturing method. All features that are the same as the first embodiment and use the same reference numerals as above will not be described again, but reference will be made to their above detailed description.

[0106] According to the second embodiment of the invention, step c) of providing the piezoelectric material 142 above the bulk handle substrate 102 is performed by epitaxially depositing a film 140 based on the piezoelectric material 142 .

[0107] In order to be able to provide a film 140 based on a piezoelectric material 142 by epitaxial deposition, a step c1) is required to provide a seed film 144 for the continued epitaxial growth of the film. This step c1) of providing a seed film 144 is also performed by epitaxial deposition of a film based on a piezoelectric material 142 at a temperature between 970° C. and 1050° C. For example, the deposited piezoelectric material 142 is based on gallium nitride GaN, but it can also be another type of material, such as aluminum nitride AlN. The seed film 144 has a thickness 6 of 50 nm to 500 nm.

[0108] According to the method of the second embodiment, when step c1) is completed and the seed film 144 is deposited on the free surface 108 of the bulk handling substrate 102, step b) of implanting 106 the bulk handling substrate 102 is performed to produce the embrittled zone 104 of the bulk support substrate 102. The implantation 106 of atomic or ionic species is carried out through the seed film 144 into the interior of the bulk support substrate 102, incident on the top surface 146 of the seed film 144.

[0109] In this embodiment, the implantation dose is less than 6×10 16 cm -2 , especially less than 5×10 16 cm -2 Such implantation doses in the bulk handle substrate 102 increase the temperature at which fracture of the handle substrate 102 along the brittle zone 104 in the handle substrate 102 can be achieved. For example, for a bulk handle substrate 102 based on silicon carbide SiC, fracture of the substrate 102 can be achieved as early as 850°C, but using 4×10 16 cm -2 The implantation dose of causes the substrate 102 to break at a temperature of 950°C.

[0110] Once the implantation 106 step b) has been completed on the bulk handle substrate 102 , a step c) of epitaxially depositing a film 140 of piezoelectric material 142 is performed. This epitaxial deposition is performed directly on the seed film 144 , enabling epitaxial deposition of a high quality film 140 of piezoelectric material 142 .

[0111] Step c) of epitaxial deposition of the piezoelectric material 142 is performed at a temperature below 950° C., in particular 900° C. The thickness of the film 140 of the piezoelectric material 142 formed is 20 μm, in particular less than 100 μm.

[0112] After step c) of the method, a donor substrate 148 is obtained, which includes a film 140 of piezoelectric material 142 with a thickness of 20 μm or less on a bulk handling substrate 102 including an embrittled zone 104, wherein a seed film 144 is sandwiched between the film 140 of piezoelectric material 142 and the bulk handling substrate 102.

[0113] For the sake of clarity, in both figures, Figure 3a and Figure 3b A method for transferring a piezoelectric thin film according to a third embodiment of the present invention is schematically shown in FIG. Figure 3a and Figure 3b All steps a) to f) shown.

[0114] The method for transferring a piezoelectric film onto a final support substrate according to the present invention comprises the step of providing a donor substrate, the donor substrate being formed by implementing the method according to the first embodiment and its variants and according to the second embodiment and its variants. Figure 1a , Figure 1b and Figure 2 The method for manufacturing the donor substrate is described.

[0115] The method for transferring a piezoelectric film starts with step a) of providing a substrate 200. The substrate 200 corresponds to the donor substrate described above and according to the present invention. That is, the substrate 200 may be Figure 1a The donor substrate 100 obtained in step d) of Figure 1b The donor substrate 138 obtained in step d) of Figure 2 The donor substrate 148 obtained in step c) of the present invention.

[0116] In all these cases, the donor substrate provided in step a) of the transfer method comprises a film 128, 140 of piezoelectric material 114, 122 having a thickness of 20 μm or less on a bulk handling substrate 102 including a brittle zone 104, wherein at least one intermediate film 118, 132, 134, 144 is sandwiched between the bulk handling substrate 102 and the film 128, 140 of piezoelectric material 114, 122.

[0117] The at least one intermediate film 118 , 132 , 134 , 144 may be a dielectric film 118 , 132 , 134 , a polymer film 118 (whether cross-linked or not), or a seed film 144 epitaxially deposited on the bulk handle substrate 102 .

[0118] Figure 3a and Figure 3b Shows the use of Figure 1a The transfer method of the substrate 100 obtained in the embodiment of the present invention is described above, but as described above, the substrates 138 and 148 can also be used. Figure 3a Steps a) to d) of the transfer method are shown, and Figure 3b Steps e) and f) of the transfer method are shown.

[0119] The method then comprises a step b) of forming an embrittled zone 204 within the film 128 of piezoelectric material 114 of the donor substrate 100 , so as to define a piezoelectric film 208 to be transferred to the final supporting substrate 210 .

[0120] This step of forming the embrittled zone 204 is performed by implanting atomic or ionic species 206 into the film 128 of the piezoelectric material 114 of the donor substrate 100. The atomic or ionic implantation 206 is performed in such a way that the embrittled zone 204 is located inside the film 128 of the piezoelectric material 114 and separates the piezoelectric film 208 from the remaining portion 212 of the film 128 of the piezoelectric material 114. The atomic or ionic species are implanted at a given depth of the piezoelectric thin film 124, which determines the thickness t5 of the piezoelectric film 208 to be transferred and the thickness t6 of the remaining portion 212 of the film 128 of the piezoelectric material 114. The thickness t5 is typically between 50 nm and 1 μm, in particular about 600 nm.

[0121] The resulting donor substrate 214 includes an embrittled region 204 separating the piezoelectric film 128 to be transferred from the remaining portion 212 of the film 208 of piezoelectric material 114 .

[0122] Step c) of the transfer method according to the invention comprises providing a final support substrate 210. The final substrate is a bulk silicon-based substrate. The final support substrate 210 can also be a bulk substrate based on silicon carbide SiC, polycrystalline SiC, polyAIN or a sintered ceramic material.

[0123] According to the present invention, the final support substrate may include a film 216. The film 216 may be a dielectric film, such as a silicon oxide-based film, or a silicon nitride Si3N4 film, or a dielectric film including nitride and silicon oxide (silicon oxynitride) SiO x N y The film 216 may also be formed of aluminum oxide A.2O3, hafnium oxide HfO2 or tantalum oxide Ta2O5 or other materials with specific functional properties, such as diffusion barrier, acoustic impedance value or capture of pollutants. The thickness of the film 216 is between 2nm and 1000nm. Depending on the bonding technology used, the film 216 may also be silicon or amorphous carbon or a metal film.

[0124] Step d) of the transfer method according to the invention comprises assembling the donor substrate 214 obtained in step b) of the method with the final substrate 210 to obtain a final supporting substrate / donor substrate assembly forming a heterostructure 218. The donor substrate 214 is assembled onto the final supporting substrate 210 at the film 216 so that the film 128 of the piezoelectric material 114 of the donor substrate 214 is in contact with the film 216 of the supporting substrate 210.

[0125] Next, a step e) is performed of forming a fracture along the brittle zone 204 of the film 128 of piezoelectric material 114 to separate the piezoelectric film 208 from the remaining part 212 of the film 128 of piezoelectric material 114 of the donor substrate. This fracture step can be performed thermally or mechanically. During the thermal separation process, the temperature used is lower than 600° C., in particular lower than 300° C. For example, a heat treatment at 200° C. for 5 hours can be used to form the fracture. The thermal treatment performed makes it possible to fracture only the brittle zone 204 of the film 128 of piezoelectric material 114. In fact, during this thermal treatment, the brittle zone 104 present in the bulk processing substrate 102 is not fractured, because the heat input is not high enough for this. The temperature used is too low to fracture the brittle zone 104 in the bulk processing substrate 102.

[0126] Figure 3a The POI substrate 220 shown in step e) is produced by the piezoelectric thin film transfer method according to the present invention and comprises a final support substrate 210, a membrane 216 and a piezoelectric thin film 208 having a thickness between 50 nm and 1 μm, in particular about 600 nm.

[0127] At the end of step e) of the transfer method, a donor substrate 222 remains, which comprises the bulk handle substrate 102 with its embrittled zone 104, the intermediate film 118 and the remaining part 212 of the film 128 of the piezoelectric material 114. The thickness t6 of the piezoelectric film remaining part 212 is less than the thickness t2 of the film 128. Therefore, as long as the thickness t6 of the piezoelectric film 212 of the donor substrate remaining part 222 obtained in step e) is greater than 5 μm, the donor substrate remaining part 222 can be reused in the transfer method according to the above steps a) and e).

[0128] Therefore, according to the present invention, steps a) to e) of the transfer method are repeated at least once. Steps a) to e) of the transfer method are repeated at least once. Figure 3c Shown in the diagram.

[0129] Starting from the second iteration, step a) of the method for providing a substrate is performed with a substrate 222 corresponding to the remainder of the donor substrate 100 obtained at the end of step e) of the previous iteration, ie donor substrate remainder 222 .

[0130] In a second iteration of the method, an implantation step b) 206 is performed in the piezoelectric film 212 of the donor substrate remainder 222 to produce a brittle zone in the piezoelectric film 212, which is the piezoelectric film that remains on the donor substrate remainder 222 after the piezoelectric film 208 is transferred to the final supporting substrate 210 in the first iteration of the transfer method.

[0131] Steps b), c), d) and e) are repeated according to step e) of the first iteration to obtain again the POI substrate 230 (not shown). These steps are identical to those of the above-described transfer method.

[0132] Similarly, after a second iteration of step e) of the method, a donor substrate remainder 222, referred to as a donor substrate 232 (not shown), is obtained having a piezoelectric film 242 that is thinner than the piezoelectric film 212 because the piezoelectric film has been transferred from the piezoelectric film 212 to the final supporting substrate to form the POI substrate 230.

[0133] At the end of step e) of the second iteration, if the thickness of the remaining portion 242 of the piezoelectric film in the donor substrate 222 is greater than 5 μm, further iterations of steps a) to e) are performed to obtain another POI substrate, and so on, until the thickness of the remaining piezoelectric film 242 in the remaining portion 222 of the donor substrate is equal to or less than 5 μm.

[0134] When the thickness of the remaining piezoelectric film 242 in the donor substrate remaining portion 232 is equal to or less than 5 μm, step f) is performed without repeating the transfer method according to steps a) to e).

[0135] Step f) is a breaking step of the embrittled zone 104 of the bulk handling substrate 102 along the remaining portion of the substrate 232. In this way, the membrane 110 of the bulk handling substrate 102 bounded by the embrittled zone 104 is separated from the remaining portion 112 of the bulk handling substrate 102. Similarly, the intermediate membrane 118 and the remaining portion 212 of the piezoelectric membrane positioned on the membrane 110 are also separated from the remaining portion 112 of the bulk handling substrate 102.

[0136] Thus, after step f) of breaking the bulk handle substrate 102 along the embrittled zone 104, a remaining portion 112 of the bulk handle substrate 102 is obtained having a thickness t8. The thickness t8 of the remaining portion 112 of the bulk handle substrate 102 is less than the typical thickness t′ of the bulk handle substrate 102. In fact, the thickness t8 of the remaining portion 112 of the bulk handle substrate 102 corresponds to the thickness t′ of the initial bulk handle substrate 102 in the donor substrate manufacturing method minus the thickness t of the film 110 of the handle substrate 102 removed during the breaking of the bulk handle substrate 102.

[0137] This breaking step is performed by heat treatment.

[0138] When the support substrate supplied in step a) corresponds to Figure 1a or Figure 1b When the donor substrate 100 or 138 has been manufactured using the method for manufacturing the first embodiment and its variants, the temperature required for the fracture heat treatment along the embrittled zone of the bulk handle substrate is between 500°C and 600°C.

[0139] When the supporting dummy substrate supplied in step a) corresponds to Figure 2 When the donor substrate 148 has been manufactured using the method for manufacturing the second embodiment and its variants, the temperature required for the fracture heat treatment along the embrittled zone 104 of the bulk handle substrate 102 is greater than 950°C, in particular 1000°C.

[0140] This difference in fracture process temperature is due to the manufacturing technology of the piezoelectric material used for the donor substrate. In fact, the fracture of the brittle zone of the bulk handling substrate must occur at a different and, most importantly, higher temperature than the temperature used for the fracture of the brittle zone of the piezoelectric material of the manufactured donor substrate. The fracture of the brittle zone of the piezoelectric material must be performed before the fracture of the brittle zone of the bulk handling substrate, i.e., at a lower temperature.

[0141] Therefore, the method for transferring a piezoelectric film according to the present invention comprises two different fractures at two different positions on a donor substrate, namely a first fracture along a brittle zone in the piezoelectric film and a second fracture along a brittle zone in a bulk handling substrate. The two fractures are produced by different heat inputs, so that the two fractures cannot be produced simultaneously in the method. The two fractures can also be processed mechanically. Therefore, the piezoelectric film transfer method according to the third embodiment of the present invention makes it possible to obtain several piezoelectric on insulator (POI) substrates from a single manufactured donor substrate, and also makes it possible to obtain a remaining portion of a bulk handling substrate that can be reused in other manufacturing methods.

[0142] Figure 3d A variant of the third embodiment of the invention is shown, wherein step d) of attaching the donor substrate to the final support substrate to obtain the donor substrate / final support substrate assembly is different from the third embodiment. All other steps a), b), c), e) and f) are the same as in the third embodiment. All features that are the same as in the third embodiment and use the same reference numerals as above will not be described again, but reference is made to their above detailed description.

[0143] In this variant, before step d) of assembling the donor substrate 214 obtained in step b) of the method to the final support substrate 210, a step of depositing an additional film 220 may be performed on the donor substrate 214. The additional film 220 may be formed on the film 128 of piezoelectric material 114 by spin coating or by a thermal or plasma-assisted growth technique such as plasma enhanced chemical vapor deposition (PECVD) or physical vapor deposition (PVD).

[0144] The film 220 may be a dielectric film, such as a silicon oxide-based film, a silicon nitride Si3N4 film, or a dielectric film including nitride and silicon oxide SiO x N yThe film 220 may also be formed of aluminum oxide Al2O3, hafnium oxide HfO2 or tantalum oxide Ta2O5 or other materials with specific functional properties, such as diffusion barrier, acoustic impedance value or capture of pollutants. The thickness of the film 220 is between 2nm and 1000nm.

[0145] Thus, during the assembly step d), an assembly interface occurs between the additional film 220 of the donor substrate 214 and the film 216 of the final support substrate 210. This interface provides a stable bond between the donor substrate 214 and the final support substrate 210.

[0146] Figure 4a A method for manufacturing a donor substrate according to a fourth embodiment of the present invention is schematically shown. In the fourth embodiment, step a) of providing a bulk handle substrate differs from the first embodiment. All other steps b), c) and d) are the same as in the first embodiment. All features that are the same as in the first embodiment and use the same reference numerals as above will not be described again, but reference is made to their above detailed description.

[0147] According to a fourth embodiment of the invention, step a) of providing a bulk handle substrate comprises using the remaining portion of the bulk handle substrate obtained after step f) of the transfer method according to the third embodiment of the invention and its variants.

[0148] At the end of the fragmentation step f) of the transfer method of the third embodiment, Figure 3a As shown, a remaining substrate 112 of the bulk handle substrate 102 having a thickness t8 is obtained. The thickness t8 of the remaining portion 112 of the bulk handle substrate is less than the typical thickness t' of the bulk handle substrate used in step a) of the donor substrate manufacturing method, as shown in FIG. Figure 1a As described in.

[0149] After step f) of the transfer method, a step g) of cleaning the surface 232 of the remaining part 112 of the process substrate 102 is carried out. This cleaning step may comprise several different treatments, such as a DSS spray cleaning treatment, followed by a CMP (chemical mechanical planarization) cleaning step. CMP cleaning makes it possible to remove a 550 nm thick surface from the remaining part 112 of the process substrate 102. Thus, at the end of step g), a process substrate 236 with a final thickness t9 is obtained, which has a clean free surface 234. The thickness t9 is less than t8, i.e. the thickness of the remaining substrate 112 after the breaking step f).

[0150] These cleaning processes are necessary to make the surface 234 of the handle substrate 236 free of debris and to give it a roughness that allows the handle substrate 236 to be reused in the manufacturing method according to the first embodiment and its variations.

[0151] Once step g) has been performed, the following steps a) to d) of the manufacturing method according to the first embodiment and its variants may be performed to obtain a donor substrate for use in the piezoelectric thin film transfer method.

[0152] Therefore, the manufacturing method according to the present invention makes it possible to reuse the bulk handle substrate that has been used in the piezoelectric thin film transfer method, rather than having to provide a new bulk handle substrate that increases the cost of the method for manufacturing the POI substrate.

[0153] Therefore, recycling a portion of the bulk handle substrate according to the present invention makes it possible to reduce the costs of the method for manufacturing a POI substrate.

[0154] Figure 4b A method for manufacturing a donor substrate according to a fifth embodiment of the present invention is schematically shown. In the fifth embodiment, step a) of providing a bulk handle substrate differs from the second embodiment. All other steps b), c) and d) are the same as in the second embodiment. All features that are the same as in the second embodiment and use the same reference numerals as above will not be described again, but reference is made to their above detailed description.

[0155] According to a fifth embodiment of the invention, step a) of providing a bulk handle substrate comprises using the remaining portion of the substrate obtained after step f) of the transfer method according to the third embodiment of the invention or its variants.

[0156] At the end of the fragmentation step f) of the transfer method of the third embodiment, Figure 3a As shown, a remaining substrate 112 of the bulk handle substrate 102 having a thickness t8 is obtained. The thickness t8 of the remaining portion 112 of the bulk handle substrate is less than the typical thickness t' of the bulk handle substrate used in step a) of the donor substrate manufacturing method, as shown in FIG. Figure 1a As described in.

[0157] After step f) of the transfer method, a step g) of cleaning the surface 232 of the remaining portion 112 of the substrate 102 is carried out. This treatment step comprises one or more thermal treatments at a temperature above 950°C, in particular at a temperature of 1000°C.

[0158] This heat treatment leaves the surface 234 of the remaining portion 112 of the processed substrate 236 free of debris, so that it can be used again in the manufacturing method according to the second embodiment and its variants.

[0159] Once step g) has been performed, the following steps a) to d) of the manufacturing method according to the second embodiment and its variants may be performed to obtain a donor substrate for use in the piezoelectric thin film transfer method.

[0160] Therefore, the manufacturing method according to the present invention makes it possible to reuse the bulk handle substrate that has been used in the piezoelectric thin film transfer method, rather than having to provide a new bulk handle substrate that increases the cost of the method for manufacturing the POI substrate.

[0161] Therefore, recycling a portion of the bulk handle substrate according to the present invention makes it possible to reduce the costs of the method for manufacturing a POI substrate.

[0162] The described embodiments are only possible configurations, and it should be borne in mind that individual features of different embodiments may be combined with one another or provided independently of one another.

Claims

1. A method for transferring a piezoelectric film, the method comprising: a) providing a donor substrate (100, 138, 148), the donor substrate comprising: A bulk handle substrate (102), in particular a silicon-based bulk handle substrate, having an embrittled zone (104), and Piezoelectric material (114, 142), The piezoelectric material (114, 142) is above the bulk handling substrate (102); b) forming an embrittled zone (204) inside the piezoelectric material (114, 142) of the donor substrate (100, 138, 148), in particular forming the embrittled zone by ion implantation; c) providing a final supporting substrate (210), in particular a silicon-based substrate; d) attaching the donor substrate (100, 138, 148) to the final substrate (120) to obtain a donor substrate / final supporting substrate assembly (218); and e) forming a fracture along the brittle region (204) of the piezoelectric material (114, 142) to separate the piezoelectric film (208) from a remaining portion (222) of the donor substrate (100, 138, 148).

2. A method for transferring a piezoelectric film according to claim 1, wherein step e) of breaking along the brittle zone of the piezoelectric material is performed at a temperature lower than the temperature used for breaking at the brittle zone of the bulk handling substrate of the donor substrate.

3. A method for transferring a piezoelectric film according to one of claims 1 or 2, wherein steps a) to e) are repeated at least once and, starting from a second iteration, step a) is performed using the remaining portion (222) of the donor substrate (100, 138, 148) obtained at the end of step e) of the previous iteration.

4. A method for transferring a piezoelectric film according to claim 3, wherein steps a) to e) are repeated as long as the thickness of the piezoelectric film (212) of the remaining portion (222) of the donor substrate (100, 138, 148) obtained in step e) is greater than 5 μm.

5. The method for transferring a piezoelectric film according to one of claims 1 to 4, wherein after step e), a step f) of breaking the remaining portion (222) of the donor substrate at the brittle zone (104) of the bulk handling substrate (102) is performed.

6. The method for transferring a piezoelectric film according to claim 5, wherein when the thickness of the piezoelectric film (212) of the remaining portion (222) of the donor substrate (100, 138, 148) obtained in step e) is equal to or less than 5 μm, a breaking step f) is performed to obtain the remaining portion (112) of the block-shaped processing substrate (102).

7. The method for transferring a piezoelectric film according to claim 5, wherein the step f) of breaking the remaining portion (222) of the donor substrate (100, 138, 148) along the brittle zone (104) of the bulk handling substrate (102) is performed by heat treatment.

8. The method for transferring a piezoelectric film according to claim 1, wherein the donor substrate (100, 138, 148) provided in step a) is obtained by implementing a method for manufacturing a donor substrate for transferring a piezoelectric film to a final supporting substrate, The method for manufacturing a donor substrate for transferring a piezoelectric film to a final supporting substrate comprises the following steps: a) providing a bulk handle substrate (102), in particular a silicon-based bulk handle substrate; c) providing a piezoelectric material (114, 142) over the bulk handle substrate (102); and The method further comprises the step b) of implanting (106) the bulk handle substrate (102) to provide an embrittled zone (104) in the bulk handle substrate (102) prior to the step of supplying the piezoelectric material (114, 142).

9. The method for transferring a piezoelectric film according to claim 8, wherein step a) of providing a bulk processing substrate (102) comprises using the remaining portion (112) of the bulk processing substrate (112) obtained after step f) of the method for transferring a piezoelectric film according to claim 5.

10. The method for transferring a piezoelectric film according to claim 9, wherein step g) of processing the surface (232) of the remaining portion (112) of the bulk processing substrate (102) is performed after step f) of the method for transferring a piezoelectric film according to claim 5.

11. The method for transferring a piezoelectric film according to claim 8, wherein the step b) of implanting (106) the bulk handling substrate (102) is performed with less than 6×10 16 cm -2 , especially less than 5×10 16 cm -2 The implantation is carried out with an implantation dose of, even more particularly, the implantation of hydrogen H, helium He or the co-implantation of hydrogen H and helium He.

12. A method for transferring a piezoelectric film according to claim 8 or 11, wherein step c1) of providing an intermediate film (118, 132, 134, 144) between the bulk processing substrate (102) and the piezoelectric material (114, 142) is performed before step c) of providing the piezoelectric material (114, 142) above the bulk processing substrate (102).

13. A method for transferring a piezoelectric film according to claim 8, 11 or 12, wherein the step c) of providing a piezoelectric material (114) above the bulk handling substrate (102) comprises providing a bulk substrate based on the piezoelectric material (114).

14. A method for transferring a piezoelectric film according to claim 13, wherein the step c) of providing a piezoelectric material (114) above the bulk processing substrate (102) also includes the step of assembling the bulk processing substrate (102) with the bulk substrate based on the piezoelectric material (114), in particular by molecular bonding.

15. A method for transferring a piezoelectric film according to claim 8, 11, 12, 13 or 14, wherein step d) of thinning the piezoelectric material (114) is performed, in particular by grinding, and more particularly step d) is performed during the method of manufacturing a donor substrate for transferring the piezoelectric film to a final supporting substrate.

16. The method for transferring a piezoelectric film according to claim 15, wherein the step d) of thinning the piezoelectric material (114) is performed to obtain a film (128) of the piezoelectric material (114) having a thickness of 30 μm or less, in particular 20 μm or less.

17. A method for transferring a piezoelectric film according to claim 8, 11 or 12, wherein the step c) of providing a piezoelectric material (142) above the bulk processing substrate (102) is performed by epitaxially depositing a film (140) based on the piezoelectric material (142) on the bulk processing substrate (102).

18. The method for transferring a piezoelectric film according to claim 17, wherein the epitaxial deposition step is performed at a temperature below 950°C, in particular below 900°C.

19. A method for transferring a piezoelectric film according to claim 1, wherein the donor substrate (100, 138, 148) provided in step a) of the transfer method is characterized in that the embrittlement zone (104) is positioned at a depth t of 500 nm in the bulk processing substrate (112), in particular at a depth t of 300 nm in the bulk processing substrate (112), and even more particularly at a depth t of less than 300 nm in the bulk processing substrate (112).

20. A method for transferring a piezoelectric film according to claim 1 or 19, wherein the donor substrate (100, 138, 148) provided in step a) of the transfer method is characterized in that the bulk handling substrate is a silicon carbide SiC substrate and the piezoelectric material is gallium nitride GaN.

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