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

Abstract

The present invention relates to a method for manufacturing a donor substrate for transferring a piezoelectric film onto a final support substrate, comprising the steps of a) providing a bulk handling substrate (102), in particular based on silicon, and c) providing a piezoelectric material (114, 142) above the bulk handling substrate (102), the method further comprising the step b) of implanting (106) the bulk handling substrate (102) to create an embrittlement zone (104) in the bulk handling substrate (102) prior to step c) of providing the piezoelectric material (114, 142). The present invention further relates to donor substrates (100, 138, 148), in particular donor substrates obtainable by the manufacturing method according to the invention, and to a method for transferring a piezoelectric thin film using the donor substrates (100, 138, 148) according to the invention.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a donor substrate for use in a piezoelectric thin film transfer method, and to a donor substrate obtained by such a method. [Background technology]

[0002] Piezoelectric-on-insulator (POI) substrates comprise a thin film of piezoelectric material on a substrate. To fabricate such POI substrates, the method used involves transferring the piezoelectric thin film from a thick substrate of piezoelectric material onto a final support substrate.

[0003] To achieve this, a donor substrate is first used, and a bulk substrate of piezoelectric material is bonded to a handling substrate by adhesive bonding, in particular using a polymer film, or by molecular bonding. Next, the donor substrate undergoes a thinning step to form a thinner piezoelectric film before being bonded to a support substrate. Finally, the piezoelectric film is mechanically or thermally transferred to the final substrate via a pre-fabricated fracture zone in the thinned piezoelectric film. The donor substrate is introduced into the method to limit the adverse effects of differences in thermal expansion coefficients between the piezoelectric material and the final POI support substrate. Heat treatment is used to strengthen the bonding interface between the different substrates and transfer the thin film. Examples of this type of method are described in WO 2019 / 186032 (A1) or WO 2019 / 002080 (A1).

[0004] After multiple piezoelectric films have been transferred to the final support substrate, the remainder of the donor substrate is discarded because it can no longer be used in any manufacturing process due to the thickness limit at which the transfer of the piezoelectric film to the final substrate is no longer feasible. Therefore, a new donor substrate needs to be manufactured using a new handling substrate so that the piezoelectric film transfer process can be carried out again for the fabrication of the POI substrate.

[0005] As a result, such methods are expensive because a new, newly manufactured handling substrate must be used for each method of manufacturing a donor substrate for the transfer of a piezoelectric thin film. Summary of the Invention

[0006] One object of the present invention is to remedy the aforementioned drawbacks, in particular to provide a method for manufacturing a donor substrate that makes it possible to reduce the cost of the manufacturing method, and therefore also the cost of a piezoelectric film transfer method that uses such a donor substrate.

[0007] The object of the present invention is achieved by a piezoelectric thin film transfer method comprising: a) providing a donor substrate, in particular a silicon-based bulk handling substrate having an embrittlement zone and a piezoelectric material above the bulk handling substrate; b) forming an embrittlement zone inside the piezoelectric material of the donor substrate, in particular by ion implantation; c) providing a final support substrate, in particular a silicon-based substrate; d) attaching the donor substrate to the final substrate to obtain a donor substrate / final support substrate assembly; and e) fracturing the piezoelectric material along the embrittlement zone to separate the piezoelectric film from the remainder of the donor substrate.

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

[0009] According to one embodiment, steps a) to e) can be repeated at least once, and from the second iteration onwards, step a) can be carried out using 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) can be repeated as long as the thickness of the piezoelectric film on the remaining donor substrate obtained in step e) is greater than 5 μm.

[0011] In one embodiment, step f) of fracturing the donor substrate remainder at the embrittlement zone of the bulk handling substrate can be performed after step e).

[0012] According to one embodiment, the crushing step f) can be carried out when the piezoelectric film thickness of the donor substrate remnant obtained in step e) is less than or equal to 5 μm, in order to obtain a bulk handling substrate remnant.

[0013] In one embodiment, step f) of fracturing the donor substrate remainder along the embrittlement zone of the bulk handling substrate can be performed by a heat treatment.

[0014] According to one embodiment, the donor substrate provided in step a) can be obtained by carrying out a method for manufacturing a donor substrate for transferring a piezoelectric film onto a final support substrate, which method for manufacturing a donor substrate for transferring a piezoelectric film onto a final support substrate can comprise the steps of a) providing a bulk handling substrate, in particular based on silicon, and c) providing a piezoelectric material on the bulk handling substrate, and further comprising the step of b) implanting the bulk handling substrate prior to the step of providing the piezoelectric material in order to provide an embrittlement zone in the bulk handling substrate.

[0015] According to one embodiment, step a) of providing a bulk handling substrate (102) can include using the remainder of the bulk handling substrate obtained after step f) of the piezoelectric thin film transfer method described above.

[0016] In one embodiment, step g) of treating the surface of the bulk handling substrate remainder can be performed after step f) of the piezoelectric film transfer method described above.

[0017] According to one embodiment, the step b) of implanting the bulk handling substrate comprises implanting 6×10 16 cm -2 Less than 5×10 16 cm -2It can be performed with an implantation amount of less than 1000 Å, and more specifically with implantation of hydrogen H, helium He, or co-implantation of hydrogen H and helium H.

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

[0019] According to one embodiment, said step c) of providing a piezoelectric material above a bulk handling substrate may comprise providing a bulk piezoelectric material based substrate.

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

[0021] According to one embodiment, step d) of thinning the piezoelectric material can be carried out in particular by grinding, more particularly during the method for manufacturing a donor substrate for transferring the piezoelectric film onto a final support substrate.

[0022] According to one embodiment, this step d) of thinning the piezoelectric material can be carried out in order to obtain a film of piezoelectric material having a thickness of less than or equal to 30 μm, in particular less than or equal to 20 μm.

[0023] According to one embodiment, said step c) of providing a piezoelectric material above a bulk handling substrate may be performed by epitaxial deposition of a piezoelectric material-based film on the bulk handling substrate.

[0024] According to one embodiment, the epitaxial deposition step may be carried out 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 embrittlement zone is located at a depth t within the bulk handling substrate of 500 nm, in particular at a depth t within the bulk handling substrate of 300 nm, and even more particularly at a depth t within the bulk handling substrate of less than 300 nm.

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

[0027] The subject matter of the present invention can further be achieved by a method for manufacturing a donor substrate for transferring a piezoelectric film onto a final support substrate, comprising the steps of a) providing a bulk handling substrate, in particular based on silicon, and c) providing a piezoelectric material on the bulk handling substrate, characterized in that the method further comprises, before the step c) of providing the piezoelectric material, a step b) of implanting the bulk handling substrate in order to provide an embrittlement zone in the bulk handling substrate.

[0028] Therefore, the donor substrate manufactured by the method according to the present invention can be fractured with the bulk handling substrate in a subsequent step. The fracture of the donor substrate at the embrittlement zone of the bulk handling substrate generates a bulk handling substrate remnant that can be reused in a subsequent method. In this way, the costs associated with manufacturing the bulk handling substrate can be reduced by reusing or recycling part of the bulk handling substrate.

[0029] According to one embodiment, step b) of implanting the bulk handling substrate comprises implanting 6×10 16 cm -2 Less than 5×10 16 cm -2 It can be carried out with an implantation dose of less than 1000 keV, and even more specifically with implantation of hydrogen H, helium He, or co-implantation of hydrogen and helium H / He.

[0030] In this way, the embrittlement zone in the bulk handling substrate is positioned at a depth of less than 500 nm, in particular 300 nm, within the bulk handling substrate. This depth allows for the creation of a thin film of the bulk handling substrate that is removed in the corresponding fracturing step. In this way, the remaining bulk handling substrate still has a viable thickness for reuse in subsequent methods.

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

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

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

[0034] The method according to the invention can be used with a wide variety of piezoelectric materials that play a key role in devices utilizing the piezoelectric effect, such as lithium tantalate (LTO), lithium niobate (LNO), aluminum nitride (AIN), lead zirconate titanate (PZT), langasite (LGS) or langatate (LGT).

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

[0036] In this way, the assembly step allows for the combination of many different materials. Additionally, the interface between the bulk handling substrate and the piezoelectric material is a stable assembly interface.

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

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

[0039] According to one embodiment, the thinning step d) can be carried out so as to obtain a piezoelectric material thickness of less than or equal to 30 μm, in particular less than or equal to 20 μm.

[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 onto a final support substrate to form a piezoelectric-on-insulator (POI) substrate. In the method for fabricating a POI substrate, the piezoelectric material and the final support substrate material have very different thermal expansion coefficients, resulting in significant deformation of the assembly. In such a method, the donor substrate is used to hold the thick piezoelectric substrate between a handling substrate and a support substrate. The selection of materials and thicknesses for the handling substrate and the final support substrate reduces the effect of the thermal expansion coefficient and thus minimizes deformation of the assembly when applying heat treatments in the method for fabricating a piezoelectric-on-insulator (POI) substrate. For example, the difference in the thermal expansion coefficient between the handling substrate material and the final support substrate material is 5% or less, preferably 0% or less.

[0041] According to one embodiment, the step c) of providing a piezoelectric material may be performed by epitaxial deposition of a piezoelectric material-based film.

[0042] In this way, the method makes it possible to obtain in a controlled manner films of piezoelectric material with a desired thickness and quality suitable for use in SAW devices. For example, films 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 carried out at a temperature below 950°C, in particular below 900°C.

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

[0045] The object of the present invention can also be achieved by a donor substrate, in particular comprising a silicon-based bulk handling substrate, in particular a donor substrate obtained by the method described above, and a piezoelectric material above the bulk handling substrate, characterized in that the bulk handling substrate comprises an embrittlement zone.

[0046] Such donor substrates, particularly those manufactured using the methods described herein, can be used to transfer piezoelectric thin films onto support substrates to create piezoelectric-on-insulator (POI) substrates. Additionally, the presence of a weakened zone in the bulk handling substrate allows for the recycling of portions of the donor substrate by fracturing the donor substrate at the weakened zone upon completion of the piezoelectric thin film transfer method. Fracturing along the weakened zone of the handling substrate can be achieved by thermal or mechanical treatment.

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

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

[0049] This material combination is very interesting for subsequent use in power devices handling voltages of 1,200 V and above, or in optoelectronic devices such as radio frequency (RF) or microLEDs.

[0050] The object of the present invention can also be achieved by a method for transferring a piezoelectric thin film, comprising: a) providing a donor substrate comprising a bulk handling substrate having a weakened zone as described above or obtained by carrying out a manufacturing method as described above; b) forming a weakened zone in the piezoelectric material of the donor substrate, in particular by ion implantation; c) providing a final support substrate, in particular based on silicon; d) attaching the donor substrate to the final support substrate to obtain a donor substrate / final support substrate assembly; and e) fracturing the piezoelectric material along the weakened zone to separate the piezoelectric film from the remainder of the donor substrate.

[0051] In the method for manufacturing a piezoelectric-on-insulator (POI) substrate, the piezoelectric material and the support substrate material have very different thermal expansion coefficients, resulting in significant deformation of the assembly. In this method, thanks to the use of a donor substrate, a thick piezoelectric substrate is held between a handling substrate and a final support substrate. The selection of materials and thicknesses for the handling substrate and the final support substrate ensures a specific symmetry in the thermal expansion coefficients, thus minimizing deformation of the assembly when applying heat treatment in the method for manufacturing a piezoelectric-on-insulator (POI) substrate. For example, the difference in the thermal expansion coefficients between the handling substrate material and the final support substrate material is 5% or less, preferably 0% or less.

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

[0053] Therefore, only fracture in the embrittlement zone of the piezoelectric material is performed during this step of the method: the energy input required to effect fracture in the embrittlement zone of the bulk handling substrate is insufficient, since fracture occurs at a lower temperature than the required energy input.

[0054] According to one embodiment, steps a) to e) can be repeated at least once, with step a) being carried out from the second iteration onwards using the remainder of the donor substrate obtained at the end of step e) of the previous iteration.

[0055] In this way, the donor substrate remnants can be recycled and even reused several times, which 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) can be repeated as long as the thickness of the piezoelectric film on the remaining donor substrate obtained in step e) is greater than 5 μm.

[0057] Therefore, as long as the piezoelectric film remaining on the donor substrate remnant is thick enough to allow the piezoelectric thin film to be transferred onto the final support substrate, the donor substrate remnant can be recycled and reused, which reduces the cost of the method since multiple POI substrates can be produced from a single donor substrate.

[0058] In one embodiment, step f) of fracturing the donor substrate remainder at the embrittlement zone of the bulk handling substrate can be performed after step e).

[0059] In this way, a bulk handling substrate remnant with a free top surface is obtained, which can be reused to fabricate new donor substrates as described above.

[0060] According to one embodiment, to obtain a bulk handling substrate remnant, a step f) can be carried out in which the donor substrate remnant obtained in step e) has a piezoelectric film thickness of 5 μm or less, and the donor substrate remnant is fractured at the embrittlement zone of the bulk handling substrate.

[0061] The step of fracturing the remainder of the donor substrate separates the remaining piezoelectric film, intermediate film, and part of the bulk handling substrate, each having a thickness of 5 μm or less, thereby obtaining a bulk handling substrate remainder having a free upper surface that can be reused to fabricate a new donor substrate as described above.

[0062] In one embodiment, step f) of fracturing the donor substrate remainder along the embrittlement zone of the bulk handling substrate can be performed by a heat treatment.

[0063] A significant heat input is required to cause fracture in the bulk handling substrate, which means that fracture of the bulk handling substrate in the embrittlement zone cannot occur during other heat treatments previously performed in piezoelectric thin film transfer methods.

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

[0065] In this way, a portion of the bulk handling substrate can be recycled and reused after it has already been used in the transfer method, which reduces the costs associated with producing the bulk handling substrate for the production of donor substrates for piezoelectric thin film transfer, and therefore the costs associated with producing POI substrates.

[0066] In one embodiment, step g) of treating the free surface of the bulk handling substrate remainder can be performed after step f) of the transfer method described above.

[0067] In this way, the free surface of the remaining bulk handling substrate is free of particles and the bulk handling substrate remainder can be reused as a bulk handling substrate for manufacturing a donor substrate. For example, processing step g) is a CMP-type cleaning step or a cleaning step using a cleaning spray. [Brief explanation of the drawings]

[0068] The invention and its advantages will be explained in more detail below by way of preferred embodiments, with particular reference to the accompanying drawings, in which reference numerals identify features of the invention, and in which:

[0069] [Figure 1a] 1 illustrates schematically a method for manufacturing a donor substrate according to a first embodiment of the present invention; [Figure 1b] 3A and 3B show diagrammatically a method for manufacturing a donor substrate according to a variant of the first embodiment of the invention; [Figure 2] 5 illustrates schematically a method for manufacturing a donor substrate according to a second embodiment of the present invention. [Figure 3a] 10A and 10B schematically illustrate steps a) to d) of a method for transferring a piezoelectric thin film according to a third embodiment of the present invention. [Figure 3b] 3a and 3b show diagrammatically steps e) and f) of the method for transferring a piezoelectric thin film according to the third embodiment of the invention; [Figure 3c] 10A to 10C show diagrams of a method for transferring a piezoelectric thin film according to a third embodiment of the present invention. [Figure 3d] 10A and 10B schematically show a method for transferring a piezoelectric thin film according to a variant of the third embodiment of the present invention. [Figure 4a] 10A and 10B schematically illustrate a method for transferring a piezoelectric thin film according to a fourth embodiment of the present invention. [Figure 4b] 10A and 10B illustrate a method for manufacturing a donor substrate according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0070] The present invention will now be described in more detail using advantageous embodiments in an exemplary manner and with reference to the drawings. It should be noted that the described embodiments are merely possible configurations, and that the individual features described above may be provided independently of one another or may be omitted entirely when implementing the present invention.

[0071] FIG. 1a illustrates a method for manufacturing a donor substrate according to a first embodiment of the present invention.

[0072] The method for manufacturing the donor substrate 100 begins with step a) of providing a bulk handling substrate 102. The bulk substrate is a single material-based substrate, typically 300 μm to 800 μm thick.

[0073] The bulk handling substrate 102 is advantageously made from a material that has a thermal expansion coefficient close to that of the material of the final support substrate onto which the piezoelectric thin film is to be transferred, where "close" means that the difference in thermal expansion coefficient between the handling substrate material 102 and the final support substrate material is 5% or less, preferably 0% or less.

[0074] The bulk handling substrate 102 may be a silicon-based substrate. In one embodiment, the bulk handling substrate 102 may also be sapphire (Al2O3), aluminum nitride (AlN), silicon carbide (SiC), or gallium arsenide (GaAs) based. The bulk handling substrate 102 may be a crystalline or polycrystalline substrate.

[0075] According to the invention, step b) consists of forming an embrittlement zone 104 in the bulk handling substrate 102. The formation of the embrittlement zone 104 is achieved by step b) of implanting 106 atomic or ionic species into the bulk handling substrate 102. The implantation 106 of the atoms or ions is carried out on the free surface 108 of the bulk handling substrate 102. The implantation 106 of the atoms or ions can be carried out in such a way that the embrittlement zone 104 is located inside the bulk handling substrate 102 at a depth t from the free surface 108 and separates the membrane 110 from the remaining part 112 of the bulk handling substrate 102. The atomic or ionic species are implanted to a given depth t in the bulk handling substrate 102 and determine the thickness t of the membrane 110. The thickness t is of the order of 300 nm, in particular less than 300 nm.

[0076] The ion implantation 106 can be an implantation of hydrogen H+ ions or helium He2+ ions, or a co-implantation of hydrogen H and helium He ions. The implantation dose of the ion species is 6×10 16 cm -2 In particular, the implantation dose is less than 4×10 for silicon handling substrates. 16 cm -2 From 6 x 10 16 cm -2 It is between.

[0077] In one embodiment, a surface treatment step on the free surface 108 of the bulk handling substrate 102 can be performed before the implantation 106 of the bulk handling substrate 102, for example an RCA type cleaning treatment.

[0078] In step c), a piezoelectric material 114 is provided above the bulk handling substrate 102 .

[0079] This is preferably a bulk substrate 116 formed from a single piezoelectric material 114 having a thickness t1 typically of at least about 300 μm, preferably 300 μm to 800 μm.

[0080] The piezoelectric material 114 can be, for example, lithium tantalate (LTO), lithium niobate (LNO), aluminum nitride (AIN), lead zirconate titanate (PZT), langasite (LGS), or langatate (LGT).

[0081] According to the present invention, step c1) of providing at least one intermediate film 118 between the bulk handling substrate 102 and the piezoelectric material 114 is performed before step c) so that the intermediate film 118 is sandwiched between the bulk handling substrate 102 and the piezoelectric material 114.

[0082] An intermediate film 118 can be provided on the bulk handling substrate 102, in particular on the free surface 108 of the bulk handling substrate 102. The intermediate film 118 can be deposited directly on the free surface 108 of the bulk handling substrate 102. The intermediate film 118 can be formed on the free surface 108 of the bulk handling substrate 102 by spin coating or by thermal or plasma-assisted growth techniques such as plasma-enhanced chemical vapor deposition (PECVD) or physical vapor deposition (PVD).

[0083] Before the intermediate film 118 is formed, one or more steps of cleaning, brushing or polishing the surface 108 of the bulk handling substrate 102 can be performed to remove the presence of particles and dust, resulting in a cleaner free surface 108 and a higher quality intermediate film 118.

[0084] The intermediate film 118 formed on the bulk support substrate 102 may be a dielectric film, such as a silicon oxide (SiOx)-based film, a silicon nitride (Si3N4)-based film, a nitride and silicon oxide (SiO x N y The intermediate film 118 formed on the bulk support substrate 102 may be an amorphous silicon or carbon or metal film, depending on the bonding technique used.

[0085] The thickness of the intermediate film 118 is not less than 2 nm and not more than 1,000 nm.

[0086] In one variant, the intermediate film 118 formed on the bulk handling substrate 102 can be a photopolymerizable polymer film, in particular based on thiolene resin. The polymer film 118 used in the present invention can be, for example, the film sold by NORLAND PRODUCTS under the reference "NOA 61". In this case, the thickness of the polymer film 118 is preferably between 1 and 10 μm.

[0087] The polymer film 118 alone allows for good adhesion to another film or substrate. Indeed, after the assembly step of the donor substrate manufacturing method, a step of treating the polymer film 118 can be carried out in order to obtain a cross-linked polymer film for bonding the handling substrate 102 to the piezoelectric material 114. The cross-linking treatment can be carried out on the polymer film 118 using heat, pressure, a change in pH or irradiation with a light beam 118, preferably a laser. The light radiation 118 or light beam is preferably ultraviolet (UV) radiation, preferably having a wavelength between 320 nm and 365 nm.

[0088] Thus, during the assembly step comprised in step c), the piezoelectric material 114 is assembled with the bulk handling substrate 102 to form the heterostructure 124 by bringing the intermediate film 118 into contact with the piezoelectric material 114. The assembly interface 126 is therefore located between the piezoelectric material 114 and the intermediate film 118 of the handling substrate 102.

[0089] According to the invention, a step d) of thinning the piezoelectric material 114 is carried out after the assembly step c) by grinding or chemical etching of the piezoelectric material 114 in order to reduce the thickness t1 of the piezoelectric material 114 to obtain a piezoelectric film 128 having a thickness t2 of the order of 20 μm, or even between 5 μm and 20 μm.

[0090] Thus, a bulk handling substrate / piezoelectric material assembly 100, also known as donor substrate 100, is achieved at the end of step d) of the method comprising a 20 μm or 5 μm to 20 μm thick piezoelectric film 128 on a bulk handling substrate 102 including an embrittlement zone 104, and the assembly interface 126 is achieved by an intermediate film 118 sandwiched between the bulk handling substrate 102 and the film 128 of piezoelectric material 114.

[0091] In one variant, the intermediate film 118 can be provided 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 .

[0092] In another embodiment, the piezoelectric material 114 can be provided directly on the bulk handling substrate 102 without an intermediate film 118 between the two.

[0093] 1b shows a variant of the first embodiment of the present invention, which differs from the first embodiment in step c1) of providing an intermediate film 118. 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 common to the first embodiment and that use the same reference numbers as above will not be described again, but refer to the detailed description above.

[0094] In step c1), an intermediate film 132 is provided on the piezoelectric material 114 and an intermediate film 134 is provided on the bulk handling substrate 102. Then, 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 a dielectric material and the interface 130 is made of an oxide-oxide bond, in particular a Si-O-Si bond, allowing a stable molecular force bond.

[0095] In another embodiment, the intermediate films 132, 134 provided on the piezoelectric material 114 and on the bulk handling substrate 102 are composed of different dielectric materials. For example, the intermediate film 132 provided on the bulk handling substrate 102 is a film of silicon nitride (Si3N4), and the intermediate film 134 provided on the piezoelectric material 114 is a film of silicon oxynitride (SiON). 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.

[0096] Thus, the donor substrate 138 is obtained after step d) of the method and comprises a piezoelectric film 128 having a thickness t2 of 20 μm or between 5 μm and 20 μm on a bulk handling substrate 102 including a weakened zone 104, and has an assembly interface 130 made by two intermediate films based on different materials 132, 134.

[0097] 2 shows a second embodiment of the present invention of a donor substrate manufacturing method. In this second embodiment, step c1) of providing an intermediate film and step c) of providing a piezoelectric material differ 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 common to the first embodiment and that use the same reference numbers as above will not be described again, but please refer to the detailed description above.

[0098] According to a second embodiment of the invention, step c) of providing a piezoelectric material 142 on the bulk handling substrate 102 is performed by epitaxial deposition of a film 140 based on the piezoelectric material 142 .

[0099] To be able to provide the piezoelectric material 142-based film 140 by epitaxial deposition, step c1) is necessary to provide a seed film 144 for the subsequent epitaxial growth of the film. This step c1) of providing the seed film 144 is also carried out by epitaxial deposition of the piezoelectric material 142-based film at a temperature between 970°C and 1,050°C. For example, the deposited piezoelectric material 142 is based on gallium nitride (GaN), but could also be another type of material, such as aluminum nitride (AlN). The thickness 6 of the seed film 144 is between 50 nm and 500 nm.

[0100] According to the method of the second embodiment, once 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 implantation 106 of the bulk handling substrate 102 is performed in order to create an embrittlement zone 104 in the bulk support substrate 102. The implantation 106 of atomic or ionic species is carried out through the seed film 144 into the bulk support substrate 102, incident on the top surface 146 of the seed film 144.

[0101] In this embodiment, the injection volume is 6×10 16 cm -2 Less than 5×10 16 cm -2 Such an implant dose in the bulk handling substrate 102 increases the temperature at which fracture of the handling substrate 102 along the embrittlement zone 104 in the handling substrate 102 can be achieved. For example, for a silicon carbide (SiC)-based bulk handling substrate 102, fracture of the substrate 102 can be achieved at temperatures as high as 850°C, but at temperatures as low as 4×10 16 cm -2 Using an implant dose of 100 Å results in spallation of the substrate 102 at a temperature of 950° C.

[0102] Once step b) 106 is implanted onto the bulk handling substrate 102, step c) epitaxially deposits a film 140 of piezoelectric material 142. This epitaxial deposition is performed directly on the seed film 144, allowing a good quality film 140 of piezoelectric material 142 to be epitaxially deposited.

[0103] The step c) of epitaxial deposition of the piezoelectric material 142 is carried out at a temperature below 950° C., in particular at 900° C. The thickness of the film 140 of the piezoelectric material 142 formed is below 20 μm, in particular below 100 μm.

[0104] After step c) of the method, a donor substrate 148 is obtained comprising a film 140 of piezoelectric material 142 having a thickness of 20 μm or less on a bulk handling substrate 102 comprising an embrittlement zone 104, and a seed film 144 is sandwiched between the film 140 of piezoelectric material 142 and the bulk handling substrate 102.

[0105] The method for transferring a piezoelectric thin film according to a third embodiment of the present invention is shown schematically in two figures, Figures 3a and 3b, for clarity. However, the transfer method according to the present invention includes all of steps a) to f) shown in Figures 3a and 3b.

[0106] 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 obtained by carrying out the method for manufacturing a donor substrate described in relation to Figures 1a, 1b and 2 according to the first embodiment and its variants of the present invention and the second embodiment and its variants of the present invention.

[0107] The method for transferring a piezoelectric thin film begins with step a) of providing a substrate 200. The substrate 200 corresponds to the donor substrate according to the invention described above, i.e., the substrate 200 may be the donor substrate 100 obtained in step d) of Fig. 1a, or the donor substrate 138 obtained in step d) of Fig. 1b, or the donor substrate 148 obtained in step c) of Fig. 2.

[0108] 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 weakened zone 104, with at least one intermediate film 118, 132, 134, 144 sandwiched between the bulk handling substrate 102 and the film 128, 140 of piezoelectric material 114, 122.

[0109] At least one intermediate film 118 , 132 , 134 , 144 can be a dielectric film 118 , 132 , 134 , a polymer film 118 whether crosslinked or not, or a seed film 144 epitaxially deposited on the bulk handling substrate 102 .

[0110] Figures 3a and 3b show a transfer method using substrate 100 obtained in Figure 1a, but as mentioned above, substrates 138 and 148 can also be used. Figure 3a shows steps a) to d) of the transfer method, and Figure 3b shows steps e) and f).

[0111] Next, the method includes a step b) of forming a weakened zone 204 in the film 128 of piezoelectric material 114 of the donor substrate 100 so as to define a piezoelectric film 208 to be transferred onto the final support substrate 210 .

[0112] This step of forming the embrittlement zone 204 is performed by implanting atomic or ionic species 206 into the film 128 of piezoelectric material 114 of the donor substrate 100. The atomic or ionic implantation 206 is performed in such a way that the embrittlement zone 204 is located inside the film 128 of piezoelectric material 114 and separates the piezoelectric film 208 from the remaining portion 212 of the film 128 of piezoelectric material 114. The atomic or ionic species are implanted to a given depth in the piezoelectric film 124, which determines the thickness t5 of the transferred piezoelectric film 208 and the thickness t6 of the remaining portion 212 of the film 128 of piezoelectric material 114. The thickness t5 is typically between 50 nm and 1 μm, and in particular around 600 nm.

[0113] The resulting donor substrate 214 includes a weakened zone 204 that separates the transferred piezoelectric film 208 from the remaining portion 212 of the film 128 of piezoelectric material 114 .

[0114] 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 may be a bulk substrate based on silicon carbide SiC, poly-SiC, polyAIN or a sintered ceramic material.

[0115] According to the invention, the final support substrate can comprise a film 216. Film 216 can be a dielectric film, for example a silicon oxide-based film, or a silicon nitride Si3N4 film, or a film containing a combination of nitride and silicon oxide (silicon oxynitride) SiO x N y The film 216 may also be made of aluminum oxide Al2O3, hafnium oxide HfO2, or tantalum oxide Ta2O5, or other materials with specific functional properties, for example, as a diffusion barrier, acoustic impedance value, or trapping of contaminating species. The thickness of the film 216 is between 2 nm and 1,000 nm. Depending on the bonding technique used, the film 216 may be a silicon or amorphous carbon or metal film.

[0116] 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 support substrate / donor substrate assembly forming a heterostructure 218. The donor substrate 214 is assembled onto the final support substrate 210 at the film 216 such that the film 128 of the piezoelectric material 114 of the donor substrate 214 is in contact with the film 216 of the support substrate 210.

[0117] Next, step e) is performed to separate the piezoelectric film 208 from the remaining portion 212 of the film 128 of piezoelectric material 114 of the donor substrate. This step can be performed thermally or mechanically. During the thermal separation, the temperatures used are below 600°C, in particular below 300°C. For example, the fracturing can be performed using a heat treatment at 200°C for 5 hours. The heat treatment performed makes it possible to destroy only the embrittlement zone 204 of the film 128 of piezoelectric material 114. In fact, the embrittlement zone 104 present in the bulk handling substrate 102 is not fractured during this heat treatment because the heat input is not high enough for this heat treatment. The temperature used is too low to fracture the embrittlement zone 104 in the bulk handling substrate 102.

[0118] The POI substrate 220 shown in step e) of FIG. 3 a is produced by the piezoelectric film transfer method according to the present invention and comprises a final support substrate 210, a film 216 and a piezoelectric film 208 having a thickness between 50 nm and 1 μm, in particular around 600 nm.

[0119] At the end of step e) of the transfer method, a donor substrate 222 also remains, comprising the bulk handling substrate 102 with the embrittlement zone 104, the intermediate film 118, and the remnant 212 of the film 128 of piezoelectric material 114. The piezoelectric film remnant 212 has a thickness t6 that is smaller than the thickness t2 of the film 128. The donor substrate remnant 222 can therefore be reused in the transfer method according to steps a) and e) described above, as long as the thickness t6 of the piezoelectric film 212 of the donor substrate remnant 222 obtained in step e) is greater than 5 μm.

[0120] Thus, according to the invention, steps a) to e) of the transfer method are repeated at least once. The repetition of steps a) to e) of the transfer method is illustrated in the diagram of Figure 3c.

[0121] From the second iteration onwards, step a) of the method for providing a substrate is carried out using a substrate 222 corresponding to the remainder of the donor substrate 100 obtained at the end of step e) of the previous iteration, i.e. the donor substrate remainder 222.

[0122] In a second iteration of the method, implantation step b) 206 is performed in the piezoelectric film 212 of the donor substrate remainder 222 to create an embrittlement zone in the piezoelectric film 212, which remains on the donor substrate remainder 222 after transfer of the piezoelectric thin film 208 onto the final support substrate 210 in the first iteration of the transfer method.

[0123] Steps b), c), d) and e) are repeated to obtain again the POI substrate 230 (not shown) according to step e) of the first iteration. The steps are the same as those described above for the transfer method.

[0124] Similarly, after the second iteration of step e) of the method, the piezoelectric thin film has been transferred from the piezoelectric film 212 to the final support substrate to form the POI substrate 230, resulting in a donor substrate remnant 222 called donor substrate 232 (not shown) having a piezoelectric film 242 that is thinner than the piezoelectric film 212.

[0125] At the end of step e) of the second iteration, if the thickness of the piezoelectric film remnant 242 in the donor substrate 232 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 donor substrate remnant 222 is 5 μm or less.

[0126] If the thickness of the piezoelectric film 242 remaining on the donor substrate remnant 232 is 5 μm or less, step f) is performed. The transfer method according to steps a) to e) is not repeated.

[0127] Step f) is a fracturing step of the remainder of the substrate 232 along the embrittlement zone 104 of the bulk handling substrate 102. In this way, the membrane 110 of the bulk handling substrate 102 bounded by the embrittlement zone 104 is separated from the remainder 112 of the bulk handling substrate 102. Similarly, the intermediate membrane 118 and the piezoelectric membrane remainder 212 arranged on the membrane 110 are also separated from the remainder 112 of the bulk handling substrate 102.

[0128] Thus, after step f) of fracturing the bulk handling substrate 102 along the embrittlement zone 104, a remnant 112 of the bulk handling substrate 102 is obtained having a thickness t8. The thickness t8 of the remnant 112 of the bulk handling substrate 102 is smaller than the thickness t' typical for the bulk handling substrate 102. In fact, the thickness t8 of the remnant 112 of the bulk handling substrate 102 corresponds to the initial thickness t' of the bulk handling substrate 102 in the donor substrate manufacturing method minus the thickness t of the film 110 of the handling substrate 102 that was removed during fracturing of the bulk handling substrate 102.

[0129] This crushing step is carried out by heat treatment.

[0130] If the support substrate provided in step a) corresponds to the donor substrate 100 or 138 of FIG. 1a or 1b and is manufactured using the method for manufacturing the first embodiment and its variants, the temperature required for the thermal treatment of fracture along the embrittlement zone of the bulk handling substrate is 500°C to 600°C.

[0131] If the support pseudo-substrate provided in step a) corresponds to the donor substrate 148 of FIG. 2 and is manufactured using the method for manufacturing the second embodiment and its variants, the temperature required for the thermal decomposition treatment along the embrittlement zone 104 of the bulk handling substrate 102 is higher than 950°C, in particular 1,000°C.

[0132] This difference in the fracture treatment temperature is due to the manufacturing technique used for the piezoelectric material of the donor substrate. Indeed, the fracture of the embrittlement zone of the bulk handling substrate must be carried out at a temperature different from, and in particular higher than, the temperature used for the fracture of the embrittlement zone of the piezoelectric material of the manufactured donor substrate. The fracture of the embrittlement zone of the piezoelectric material must be carried out before the fracture of the embrittlement zone of the bulk handling substrate, i.e. at a lower temperature.

[0133] Therefore, the method for transferring a piezoelectric thin film according to the present invention includes two different fractures at two different locations on a donor substrate: the first fracture along the embrittlement zone of the piezoelectric film, and the second fracture along the embrittlement zone of the bulk handling substrate. Because the two fractures are generated by different heat inputs, the method does not allow for simultaneous generation of the two fractures. Both fractures can also be processed mechanically. Therefore, the piezoelectric thin film transfer method according to the third embodiment of the present invention allows for the production of several piezoelectric-on-insulator (POI) substrates from a single manufactured donor substrate, and also allows for the production of bulk handling substrate remnants that can be reused in other manufacturing methods.

[0134] 3d shows a variant of the third embodiment of the present invention, which differs from the third embodiment in step d) of attaching the donor substrate to the final support substrate to obtain a donor substrate / final support substrate assembly. All other steps a), b), c), e) and f) are the same as in the third embodiment. All features that are common to the third embodiment and that use the same reference numbers as above will not be described again, but please refer to the detailed description above.

[0135] In this variant, before step d) of assembling the donor substrate 214 obtained in step b) of the method into the final support substrate 210, a step of depositing an additional film 220 on the donor substrate 214 can be carried out. The additional film 220 can be formed on the film 128 of piezoelectric material 114 by spin coating or by thermal or plasma-assisted growth techniques such as plasma-enhanced chemical vapor deposition (PECVD) or physical vapor deposition (PVD).

[0136] The film 220 may be a dielectric film, for example a silicon oxide based film, or a silicon nitride Si3N4 film, or a nitride and silicon oxide SiO x N yThe film 220 may be a film including a combination of aluminum oxide Al2O3, hafnium oxide HfO2, or tantalum oxide Ta2O5, or other materials with specific functional properties, such as a diffusion barrier, acoustic impedance value, or trapping of contaminant species. The thickness of the film 220 is between 2 nm and 1,000 nm.

[0137] Thus, during assembly step d), an assembly interface is created 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.

[0138] 4a shows a schematic diagram of a method for manufacturing a donor substrate according to a fourth embodiment of the present invention. In the fourth embodiment, step a) of providing a bulk handling substrate differs from that of the first embodiment. All other steps b), c) and d) are the same as those of the first embodiment. All features that are common to the first embodiment and that use the same reference numerals as above will not be described again, but refer to the detailed description above.

[0139] According to a fourth embodiment of the present invention, step a) of providing a bulk handling substrate comprises a step of using the remainder of the bulk handling substrate obtained after step f) of the transfer method according to the third embodiment of the present invention and its variants.

[0140] At the end of the fracturing step f) of the transfer method of the third embodiment, a remaining substrate 112 of the bulk handling substrate 102 is obtained with a thickness t8, as shown in Figure 3a. The thickness t8 of the remaining bulk handling substrate 112 is smaller than the thickness t' typical for a bulk handling substrate used in step a) of the donor substrate manufacturing method, as described in Figure 1a.

[0141] After step f) of the transfer method, a step g) of cleaning the surface 232 of the remainder 112 of the handling substrate 102 is carried out. This cleaning step can include several different processes, such as a DSS spray cleaning treatment followed by a CMP (Chemical Mechanical Planarization) cleaning step. The CMP cleaning makes it possible to remove a 550 nm thick surface from the remainder 112 of the handling substrate 102. A handling substrate 236 having a final thickness t9 is thus obtained at the end of step g) with a clean free surface 234. The thickness t9 is smaller than the thickness t8 of the remainder 112 of the handling substrate 102 after the fracturing step f).

[0142] These cleaning processes are necessary to keep the surface 234 of the handling substrate 236 free of debris and to give it a roughness that allows the handling substrate 236 to be reused in the manufacturing method according to the first embodiment and its variants.

[0143] Once step g) has been performed, the following steps a) to d) of the manufacturing method according to the first embodiment and its variations can be performed to obtain a donor substrate for use in a piezoelectric thin film transfer method.

[0144] Therefore, the manufacturing method according to the present invention makes it possible to reuse a bulk handling substrate that has already been used in a piezoelectric thin film transfer method, instead of having to provide a new bulk handling substrate, which would increase the cost of the method for manufacturing a POI substrate.

[0145] Recycling part of the bulk handling substrate according to the invention therefore makes it possible to reduce the costs of the method for manufacturing the POI substrate.

[0146] 4b shows a schematic diagram of a method for manufacturing a donor substrate according to a fifth embodiment of the present invention. In the fifth embodiment, step a) of providing a bulk handling substrate differs from that of the second embodiment. All other steps b), c) and d) are the same as those of the second embodiment. All features that are common to the second embodiment and use the same reference numerals as above will not be described again, but please refer to the detailed description above.

[0147] According to a fifth embodiment of the present invention, step a) of providing a bulk handling substrate comprises using a remainder of the substrate obtained after step f) of the transfer method according to the third embodiment of the present invention or its variants.

[0148] At the end of the fracturing step f) of the transfer method of the third embodiment, a remaining substrate 112 of the bulk handling substrate 102 is obtained with a thickness t8, as shown in Figure 3a. The thickness t8 of the remaining bulk handling substrate 112 is smaller than the thickness t' typical for a bulk handling substrate used in step a) of the donor substrate manufacturing method, as described in Figure 1a.

[0149] After step f) of the transfer method, a step g) is carried out of cleaning the surface 232 of the remaining part 112 of the handling substrate 102. This treatment step comprises one or more heat treatments at temperatures above 950°C, in particular at 1,000°C.

[0150] This heat treatment leaves the surface 234 of the remainder 112 of the handling substrate 236 free of debris so that it can be reused in the manufacturing method according to the second embodiment and its variants.

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

[0152] Therefore, the manufacturing method according to the present invention makes it possible to reuse a bulk handling substrate that has already been used in a piezoelectric thin film transfer method, instead of having to provide a new bulk handling substrate, which would increase the cost of the method for manufacturing a POI substrate.

[0153] Recycling part of the bulk handling substrate according to the invention therefore makes it possible to reduce the costs of the method for manufacturing the POI substrate.

[0154] It should be noted that the described embodiments are merely possible configurations, and that individual features of the different embodiments can be combined with one another or provided independently of one another.

Claims

1. A method for transferring a piezoelectric thin film, comprising the steps of: a) a bulk handling substrate (102), in particular silicon-based, having an embrittlement zone (104); a piezoelectric material (114, 142); providing a donor substrate (100, 138, 148) comprising: the piezoelectric material (114, 142) is above the bulk handling substrate (102); b) forming a weakened zone (204) in said piezoelectric material (114, 142) of said donor substrate (100, 138, 148), in particular by ion implantation; c) providing a final support substrate (210), in particular a silicon-based substrate; d) attaching said donor substrate (100, 138, 148) to said final substrate (120) to obtain a donor substrate / final support substrate assembly (218); e) fracturing along the weakened zone (204) of the piezoelectric material (114, 142) to separate the piezoelectric film (208) from the remainder (222) of the donor substrate (100, 138, 148); A method for transferring a piezoelectric thin film, comprising:

2. 2. The method of transferring a piezoelectric thin film of claim 1, wherein step e) of fracturing along the embrittlement zone of the piezoelectric material is performed at a temperature lower than the temperature used to effect fracturing in the embrittlement zone of the bulk handling substrate of the donor substrate.

3. 3. The method for transferring a piezoelectric thin film according to claim 1, wherein steps a) to e) are repeated at least once, and starting from the second iteration, step a) is performed using the remainder (222) of the donor substrate (100, 138, 148) obtained at the end of step e) of the previous iteration.

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

5. 5. The method for transferring a piezoelectric thin film according to claim 1, wherein step f) of fracturing the remainder (222) of the donor substrate in the embrittlement zone (104) of the bulk handling substrate (102) is performed after step e).

6. 6. The method for transferring a piezoelectric thin film according to claim 5, wherein the crushing step f) is carried out 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 5 μm or less, to obtain the remaining portion (112) of a bulk handling substrate (102).

7. 6. The method of claim 5, wherein step f) of fracturing the remainder (222) of the donor substrate (100, 138, 148) along the embrittlement zone (104) of the bulk handling substrate (102) is performed by a heat treatment.

8. said donor substrate (100, 138, 148) provided in step a) is obtained by carrying out 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 comprises: a) providing a bulk handling substrate (102), in particular a silicon-based one; c) providing a piezoelectric material (114, 142) above the bulk handling substrate (102); 2. The method of claim 1, further comprising the step of: b) injecting (106) the bulk handling substrate (102) to provide a weakened zone (104) in the bulk handling substrate (102) prior to the step of providing the piezoelectric material (114, 142).

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

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

11. The step b) of injecting (106) into the bulk handling substrate (102) is １６ cm －２ Less than, especially 5 x 10 １６ cm －２ 9. The method for transferring a piezoelectric thin film according to claim 8, wherein the method is carried out with an implantation dose of less than 1000 keV, and more particularly with implantation of hydrogen H, helium He, or co-implantation of hydrogen H and helium He.

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

13. 13. The method of claim 8, 11 or 12, wherein 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. 14. The method for transferring a piezoelectric thin film according to claim 13, wherein the step c) of providing a piezoelectric material (114) above the bulk handling substrate (102) further comprises a step of assembling the bulk handling substrate (102) with the bulk substrate based on the piezoelectric material (114), in particular by molecular bonding.

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

16. 16. The method for transferring a piezoelectric thin film according to claim 15, wherein step d) of thinning the piezoelectric material (114) is carried out so as 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. 13. The method for transferring a piezoelectric thin film according to claim 8, 11 or 12, wherein step c) of providing a piezoelectric material (142) above the bulk handling substrate (102) is performed by epitaxial deposition of the piezoelectric material (142)-based film (140) on the bulk handling substrate (102).

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

19. 2. The method for transferring a piezoelectric thin film of 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 located at a depth t within the bulk handling substrate (112) of 500 nm, specifically at a depth t within the bulk handling substrate (112) of 300 nm, and even more specifically at a depth t within the bulk handling substrate (112) of less than 300 nm.

20. 20. The method for transferring a piezoelectric thin 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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