Method for producing a substrate for epitaxial growth of layers of gallium-based III-N alloys

The method addresses the limitations of existing substrates by transferring a monocrystalline silicon carbide layer to a high-resistivity substrate, enhancing heat dissipation and reducing RF losses, thus enabling cost-effective and efficient epitaxial growth of gallium-based III-N alloys for high-power electronic devices.

JP7791178B2Active Publication Date: 2025-12-23SOITEC SA
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Patent Information

Application Number
JP2023517668
Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
Priority Date
2020-10-06
Filing Date
2021-10-04
Publication Date
2025-12-23
Estimated Expiration
2041-10-04

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Abstract

A method for manufacturing a substrate for epitaxial growth of a layer of a gallium-based III-N alloy includes providing a donor substrate of monocrystalline semi-insulating silicon carbide; implanting ion species into the donor substrate to form a weakened region that defines a thin layer of monocrystalline semi-insulating SiC to be transferred; bonding the donor substrate to a first receiver substrate via a bonding layer; separating the donor substrate along the weakened region to transfer the thin layer of monocrystalline semi-insulating SiC to the first receiver substrate; forming an additional layer of semi-insulating SiC on the transferred thin layer; bonding the additional layer to a second receiver substrate having high electrical resistivity; and separating the first receiver substrate and removing at least a portion of the bonding layer to expose the transferred layer of monocrystalline semi-insulating SiC.
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Description

[Technical Field]

[0001] [1] The present invention relates to a method for producing a substrate for the epitaxial growth of a layer of gallium nitride, a method for producing such a layer of gallium nitride, and a method for producing a high electron mobility transistor (HEMT) on such a layer of gallium nitride. [Background technology]

[0002] [2] III-N semiconductors, in particular gallium nitride (GaN), aluminum gallium nitride (AlGaN) or indium gallium nitride (InGaN), appear to be particularly promising, especially for the formation of high-power light-emitting diodes (LEDs) and electronic devices operating at high frequencies, such as high electron mobility transistors (HEMTs) or other field-effect transistors (FETs).

[0003] [3] Insofar as these III-N alloys are difficult to find in the form of large bulk substrates, they are generally formed by heteroepitaxy, i.e., by epitaxy on substrates made of different materials.

[0004] [4] The choice of such a substrate takes into account, among other things, the differences in the lattice constant and the thermal expansion coefficient between the substrate material and the III-N alloy. In particular, the greater these differences, the greater the risk of the formation of crystalline defects, such as dislocations, in the III-N alloy layer, and the greater the risk of high mechanical stresses that can lead to excessive strain.

[0005] [5] The materials most frequently considered for heteroepitaxy of III-N alloys are sapphire and silicon carbide (SiC).

[0006] [6] In addition to having a smaller difference in lattice constant from gallium nitride, silicon carbide is particularly preferred for high-power electronic applications because its thermal conductivity is significantly higher than that of sapphire and therefore can more easily dissipate the heat energy generated during the operation of the component.

[0007] [7] For radio frequency (RF) applications, semi-insulating silicon carbide, typically 10 5 It is desirable to use silicon carbide, which has an electrical resistivity of Ωcm or higher, however this material is particularly expensive and is currently only available in substrates of limited size.

[0008] [8] While silicon significantly reduces manufacturing costs and allows for the use of larger substrate sizes, III-N alloy-on-silicon structures are disadvantaged by RF losses and poor heat dissipation.

[0009] [9] Composite structures such as SopSiC or SiCopSiC structures have also been investigated [1] but have proven to be less than entirely satisfactory. These structures comprise a monocrystalline silicon layer or a monocrystalline SiC layer (intended to form a seed layer for epitaxial growth of gallium nitride) on a polycrystalline SiC substrate, respectively. Polycrystalline SiC is an inexpensive, available in large substrate sizes, and a good heat dissipating material, but these composite structures are disadvantaged by the presence of a silicon oxide layer at the interface between the monocrystalline silicon or SiC layer and the polycrystalline SiC substrate, which forms a thermal barrier that prevents heat dissipation from the III-N alloy layer to the polycrystalline SiC substrate. Summary of the Invention

[0010] (Brief Description of the Invention)

[10] It is therefore an object of the present invention to remedy the aforementioned drawbacks, particularly the size and cost limitations of semi-insulating SiC substrates.

[0011]

[11] It is therefore an object of the present invention to provide a method for producing a substrate for epitaxial growth of gallium-based III-N alloys, particularly for the formation of HEMTs or other high frequency, high power electronic devices with minimized RF losses and maximized heat dissipation.

[12] To this end, the invention provides a method for producing a substrate for the epitaxial growth of layers of gallium nitride (GaN), aluminum gallium nitride (AlGaN) or indium gallium nitride (InGaN), comprising the following successive steps: providing a single crystal semi-insulating silicon carbide donor substrate; implanting ionic species into the donor substrate to form a weakened region that defines a thin layer of single-crystal semi-insulating SiC to be transferred; bonding the donor substrate to a first receiver substrate via a bonding layer; Separating the donor substrate along the weakened region so as to transfer a thin layer of single-crystal semi-insulating SiC to a first receiver substrate; forming an additional layer of semi-insulating SiC on the transferred thin layer of semi-insulating SiC; Bonding an additional layer of semi-insulating SiC to a second receiver substrate having high electrical resistivity; separating the first receiver substrate and removing at least a portion of the bonding layer to expose the transferred layer of single-crystal semi-insulating SiC; The present invention provides a method comprising:

[0012]

[13] "High frequency" as used herein means frequencies above 3 kHz.

[0013]

[14] "High power" as used herein means a power density injected through the gate of a transistor greater than 0.5 W / mm.

[0014]

[15] "High electrical resistivity" as used herein means an electrical resistivity of 100 Ω cm or greater.

[0015]

[16] "Semi-insulating SiC" means, as used herein, 5 It means silicon carbide having an electrical resistivity of Ωcm or more.

[0016]

[17] The method makes it possible to form low-cost substrates based on silicon, diamond or ceramic, with high electrical resistivity and high thermal conductivity, available in large sizes, and including a layer of semi-insulating SiC, which allows the final structure to benefit from good properties in terms of heat dissipation and limiting RF losses. As the layer of semi-insulating SiC is in direct contact with the receiver substrate, the structure does not include any additional thermal barriers.

[0017]

[18] Direct epitaxy of semi-insulating SiC layers on high-resistivity silicon substrates results in the formation of numerous dislocations in the semi-insulating SiC due to the difference in lattice constants between silicon and silicon carbide. In contrast, the method according to the present invention allows the use of a monocrystalline semi-insulating SiC layer of optimal quality, obtained by transfer from a donor substrate, as a seed for the subsequent growth of a gallium-based III-N alloy. The remaining part of the semi-insulating SiC layer, i.e., an additional layer deposited on the side of the transferred layer opposite the III-N alloy layer, is not necessarily monocrystalline.

[0018]

[19] The use of a first receiver substrate acting as a temporary carrier allows for optimal orientation of the silicon face of the semi-insulating SiC during the various steps of the method.

[0019]

[20] According to an advantageous but optional feature of the method, these can be carried out separately or in any technically possible combination thereof.

[21] The difference in thermal expansion coefficient between the first receiver substrate and the donor substrate is 3×10 -6 K -1 is as follows:

[22] The first receiver substrate is a SiC substrate having a crystal quality lower than that of the donor substrate;

[23] The thickness of the thin layer of single-crystal semi-insulating SiC transferred to the first receiver substrate is less than 1 μm;

[24] the bonding layer is formed from a material that is thermally stable during formation of the layer of semi-insulating SiC and that can be removed from the interface between the transferred layer of single-crystal semi-insulating SiC and the first receiver substrate;

[25] The bonding layer is a layer of silicon nitride or gallium nitride;

[26] The step of removing at least a portion of the bonding layer comprises chemical etching, laser delamination, and / or application of mechanical stress;

[27] An additional layer of semi-insulating SiC is formed by co-depositing silicon, carbon, and vanadium.

[28] The second receiver substrate is a silicon substrate having an electrical resistivity of 100 Ω cm or more;

[29] The additional layer of semi-insulating SiC has a thickness comprised between 1 and 5 μm;

[30] The second receiver substrate is a polycrystalline SiC substrate, a diamond substrate, or a polycrystalline AlN substrate;

[31] The additional layer of semi-insulating SiC has a thickness of 80 μm or less;

[32] Ion species are implanted through a silicon surface of a donor substrate, and the silicon surface of the donor substrate is bonded to a first receiver substrate such that, after the bonding layer is removed, the silicon surface of the transferred layer of single-crystalline semi-insulating SiC is exposed;

[33] The method further comprises recycling the segments of the donor substrate separated from the transferred layer for the purpose of forming new donor substrates.

[0020]

[34] Another subject of the invention relates to a method for producing a layer of a gallium-based III-N alloy on a substrate obtained using the method described above.

[0021]

[35] The method further comprises: providing a substrate manufactured using a method such as those described above; epitaxially growing a layer of gallium nitride on the silicon surface of the transferred layer of monocrystalline semi-insulating SiC of the substrate; Includes:

[0022]

[36] The gallium nitride layer typically has a thickness comprised between 1 and 2 μm.

[0023]

[37] Another subject of the invention relates to a method for manufacturing high electron mobility transistors (HEMTs) on layers of such III-N alloys.

[38] The method further comprises: epitaxy of a layer of gallium nitride using a method such as those described above; forming a heterojunction by epitaxy on the layer of gallium nitride a layer of III-N material other than gallium nitride; forming a channel of a transistor at the same level as the heterojunction; forming a source, a drain and a gate of a transistor on the channel; Includes: [Brief explanation of the drawings]

[0024] Further features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings. [Figure 1] FIG. 1 is a schematic cross-sectional view of a single-crystalline semi-insulating SiC donor substrate. [Figure 2] 2 is a schematic cross-sectional view of the donor substrate of FIG. 1 in which a weakened region has been formed by implantation with ionic species to define a thin layer to be transferred. [Figure 3] FIG. 1 is a schematic cross-sectional view of a temporary carrier covered with a removable bonding layer. [Figure 4] 4 is a schematic cross-sectional view of the temporary carrier of FIG. 3 bonded to the donor substrate of FIG. 2 via a removable bonding layer. [Figure 5] FIG. 1 is a schematic cross-sectional view of a donor substrate being separated along a weakened region to transfer a thin layer of single-crystalline semi-insulating SiC to a temporary carrier. [Figure 6] FIG. 10 is a schematic cross-sectional view of a thin layer of single-crystal SiC transferred onto a temporary carrier after the free surface of the temporary carrier has been polished. [Figure 7]Schematic cross-sectional view in which an additional layer of semi-insulating SiC is formed on a thin layer of transferred single-crystalline semi-insulating SiC. [Figure 8] Schematic cross-sectional view in which the structure of FIG. 7 is bonded to a receiver substrate through an additional layer of semi-insulating SiC. [Figure 9] Schematic cross-sectional view of removing temporary carriers from the structure of FIG. 8 by chemical etching of a removable bonding layer so as to expose the silicon surface of the transferred semi-insulating SiC layer. [Figure 10] Schematic cross-sectional view in which a layer of GaN is formed epitaxially on the silicon surface of the transferred semi-insulating SiC layer. [Figure 11] Schematic cross-sectional view in which a heterojunction is formed by epitaxy of a layer of a III-N alloy different from GaN on the layer of GaN.

[0025] For ease of viewing the figures, the various layers are not necessarily shown to scale.

BEST MODE FOR CARRYING OUT THE INVENTION

[0026] (Detailed Description of Embodiment)

[52] The present invention provides a method for manufacturing a substrate for epitaxially growing a gallium-based binary or ternary III-N alloy. The alloy includes gallium nitride (GaN), aluminum gallium nitride (Al x Ga 1-x N, where 0 < x < 1 and is abbreviated as AlGaN hereinafter) and indium gallium nitride (In x Ga 1-x N, where 0 < x < 1 and is abbreviated as InGaN hereinafter). For the sake of brevity, in the remainder of this specification, the manufacture of a substrate for epitaxially growing a layer of GaN will be described. However, those skilled in the art can adjust the growth conditions to form a layer of AlGaN or InGaN, and the substrate useful for this epitaxial growth remains the same.

[0027]

[53] The method uses a donor substrate of monocrystalline semi-insulating silicon carbide (SiC), and a thin layer of the donor substrate transferred to a first receiver substrate using the Smart Cut™ process serves as a seed for growing an additional layer of semi-insulating SiC, which is not necessarily monocrystalline. As will be seen below, the additional layer of semi-insulating SiC allows a thickness of semi-insulating SiC large enough to substantially reduce RF losses to be provided in the final structure at an optimized cost, as long as only the segment of said layer intended for the growth of the GaN layer is monocrystalline.

[0028]

[54] For this purpose, a single-crystalline semi-insulating SiC donor substrate with excellent crystalline quality, i.e., a substrate that is particularly free of dislocations, is selected.

[0029]

[55] In certain embodiments, the donor substrate may be a bulk substrate of single-crystal semi-insulating SiC. In other embodiments, the donor substrate may be a composite substrate including a surface layer of single-crystal semi-insulating SiC and at least one other layer of another material, where the layer of single-crystal semi-insulating SiC has a thickness of 0.5 μm or greater.

[0030]

[56] Silicon carbide comes in a variety of crystalline forms (also called polytypes). The most common are the 4H, 6H, and 3C forms. Preferably, the single crystal semi-insulating silicon carbide is selected from the 4H and 6H polytypes, although any polytype can be used to practice the present invention.

[0031]

[57] The figure shows a bulk substrate 10 of single crystal semi-insulating SiC.

[0032]

[58] As known per se, such a substrate has a silicon face 10-Si and a carbon face 10-C, as shown in FIG.

[0033]

[59] Currently, GaN epitaxy is mainly performed on the silicon face of semi-insulating SiC. However, it is possible to grow GaN on the carbon face of semi-insulating SiC. The orientation of the donor substrate during this process (silicon face / carbon face) is selected depending on the face of the semi-insulating SiC on which the GaN layer is intended to grow.

[0034]

[60] Referring to Figure 2, ionic species are implanted into a donor substrate 10 to form a weakened region 12 that defines a thin layer 11 of single crystal semi-insulating SiC. The implanted species typically include hydrogen and / or helium. Those skilled in the art will be able to define the required implant dose and energy.

[0035]

[61] If the donor substrate is a composite substrate, the implantation is performed into a surface layer of monocrystalline semi-insulating SiC of said substrate.

[0036]

[62] The ionic species are preferably implanted through the silicon face 10-Si of the donor substrate. As will be seen below, this orientation of the donor substrate allows the silicon face of the semi-insulating SiC to be placed at the surface of the final substrate on which it is intended to grow a layer of GaN, which is preferred. However, if it is envisioned to grow a layer of GaN on the carbon face of the semi-insulating SiC, the ionic species must be implanted through the carbon face 10-C of the donor substrate.

[0037]

[63] The thin layer of monocrystalline semi-insulating SiC 11 preferably has a thickness of less than 1 μm. In particular, such a thickness is achievable on an industrial scale using the Smart Cut™ process. In particular, implantation tools available on industrial production lines allow such implantation depths to be obtained.

[0038]

[64] Referring to Figure 3, a first receiver substrate 20 is also provided.

[0039]

[65] The primary function of the first receiver substrate is to temporarily hold the layer of monocrystalline semi-insulating SiC 11 between the transfer of the layer of monocrystalline semi-insulating SiC 11 from the donor substrate and the growth of an additional layer of semi-insulating SiC on the layer of monocrystalline semi-insulating SiC.

[0040]

[66] For this purpose, the first receiver substrate is selected to have a coefficient of thermal expansion substantially equal to that of the semi-insulating SiC so as not to generate stress or strain during the formation of the additional layer of semi-insulating SiC. Thus, the first receiver substrate and the donor substrate (or the layer of monocrystalline semi-insulating SiC in the case of a composite donor substrate) have thermal expansion coefficients that differ by an absolute value of 3 × 10 -6 K -1 It is particularly advantageous that:

[0041]

[67] The first receiver substrate is also preferably made of SiC to minimize the difference in thermal expansion coefficients. It is particularly advantageous for the first receiver substrate 20 to be a SiC substrate with a lower crystalline quality than that of the donor substrate. This means that the first receiver substrate may be a polycrystalline SiC substrate, or indeed a substrate of monocrystalline SiC, but may contain dislocations of all types (as opposed to the monocrystalline semi-insulating SiC of the donor substrate, which is chosen for its excellent crystalline quality to ensure the quality of the GaN epitaxial layer). Such a substrate with lower crystalline quality has the advantage of being cheaper than a substrate of the same quality as the donor substrate, while still being perfectly suited to the function of a temporary carrier.

[0042]

[68] Referring to Figure 4, a donor substrate 10 comprising a thin layer 11 of single crystal SiC is bonded to a first receiver substrate 20.

[0043]

[69] To ensure good adhesion of the donor substrate to the first donor substrate, a bonding layer 21 is formed at the interface between the substrates.

[0044]

[70] In Figure 3 the bonding layer 21 is formed on the first receiver substrate 20, but in other embodiments not shown the bonding layer may be formed on the donor substrate (on the side of the thin layer 11), or indeed partly on the donor substrate and partly on the first receiver substrate.

[0045]

[71] The bonding layer is formed from a material that remains thermally stable during the subsequent formation of an additional layer of semi-insulating SiC on thin layer 11.

[0046]

[72] For reference, epitaxy of 4H- or 6H-SiC is typically performed at temperatures above 1500°C, so the selected bonding layer material will not degrade or dissociate at such temperatures when the additional layer of semi-insulating SiC is formed by epitaxy. However, unless excellent crystalline quality is required for the additional layer of semi-insulating SiC, it is not necessary to use an epitaxy method. Therefore, a faster deposition method at a lower temperature can be used, resulting in a polycrystalline additional layer or an additional layer containing dislocations, thereby reducing the time and cost required to manufacture the substrate.

[0047]

[73] Additionally, bonding layer material can be removed from the interface between the transferred layer of monocrystalline semi-insulating SiC and the first receiver substrate 20, for example, by selective etching, optionally assisted by plasma.

[0048]

[74] According to one preferred embodiment, the bonding layer is a layer of silicon nitride or gallium nitride, the thickness of said layer being typically comprised between 10 nm and several hundred nanometers.

[0049]

[75] Referring to Figure 5, the donor substrate is separated along the weakened region 12. In a manner known per se, the separation may be caused by a heat treatment, by mechanical action, or by a combination of these means.

[0050]

[76] The effect of this separation is to transfer a thin layer of single-crystalline semi-insulating SiC 11 to a first receiver substrate 20. The remaining portion of the donor substrate 10' may optionally be recycled for another use.

[0051]

[77] As shown in Figure 6, the free surface of the transferred single-crystal semi-insulating SiC layer 11 is the carbon surface 11-C (the silicon surface 11-Si is on the side of the bonded interface). This surface is polished, for example by chemical mechanical polishing (CMP), to remove defects related to the implantation of ionic species and to reduce the roughness of layer 11.

[0052]

[78] Referring to Figure 7, an additional layer 13 of semi-insulating SiC is formed on the thin layer of monocrystalline semi-insulating SiC 11. The polytype of the SiC of the additional layer is advantageously the same as the polytype of the transferred layer.

[0053]

[79] As mentioned above, the additional layer 13 does not necessarily have to be monocrystalline, but can be polycrystalline, which allows deposition to be carried out at lower temperatures than epitaxy. In any case, the small difference in thermal expansion coefficient between the material of the first receiver substrate and SiC minimizes the mechanical stresses generated in the stack.

[0054]

[80] There are various techniques for forming semi-insulating SiC. In one embodiment, a layer of SiC is doped with vanadium during its epitaxial growth. In another embodiment, silicon, carbon, and vanadium are simultaneously deposited using appropriate precursors in an epitaxial reactor.

[0055]

[81] The additional layer of semi-insulating SiC advantageously has a thickness greater than 1 μm so as to significantly contribute to the dissipation of heat within the final structure. This thickness is greater than can be achieved directly with the Smart Cut™ process using commercially available equipment. In addition, this additional layer can be formed by a less expensive method than the transferred donor substrate layer.

[0056]

[82] Thus, a method consisting in transferring a layer of monocrystalline semi-insulating SiC having a thickness of less than 1 μm and then forming a layer of semi-insulating SiC, not necessarily monocrystalline, by epitaxy on said transferred layer makes it possible to circumvent the technical limitations of industrially available implantation tools for carrying out the Smart Cut™ process and to reduce the costs of the manufacturing method.

[0057]

[83] Referring to Figure 8, a second receiver substrate 40 having high electrical resistivity is provided and bonded to the layer of semi-insulating SiC 13. For example, the second receiver substrate may be a silicon substrate having an electrical resistivity of 100 Ωcm or more, or preferably a polycrystalline SiC substrate, a polycrystalline AlN substrate, or a diamond substrate.

[0058]

[84] The thickness of the additional layer of semi-insulating SiC 13 is possibly selected depending on the material of the second receiver substrate. Thus, if the second receiver substrate is a silicon substrate with high electrical resistivity, the additional layer of semi-insulating SiC 13 advantageously has a thickness comprised between 1 and 5 μm. If the second receiver substrate is made of polycrystalline AlN, diamond or polycrystalline SiC, it may be advantageous for the additional layer of semi-insulating SiC 13 to have a much larger thickness, possibly up to 80 μm, for example about 50 to 80 μm, in order to improve the dissipation of heat in the final structure.

[0059]

[85] Next, at least a portion of bonding layer 21 is removed to separate the first receiver substrate from the remainder of the structure. During this removal, layer 21 must be sufficiently damaged to allow separation from the structure. Any suitable means may be used. For example, without limitation, the bonding layer may be removed by chemical etching, laser delamination, and / or application of mechanical stress.

[0060]

[86] Thus, at the end of this separation, a structure remains consisting successively of the second receiver substrate 40, the additional layer of semi-insulating SiC 13 and the thin layer of transferred monocrystalline semi-insulating SiC 11, as shown in Figure 9. Any residues of the bonding layer 21 are removed by polishing and / or etching.

[0061]

[87] The exposed surface of the transferred layer 11 is the silicon surface of the monocrystalline semi-insulating SiC, which is favorable for epitaxial growth of GaN. In this way, a substrate suitable for epitaxial growth of III-N alloys is formed.

[0062]

[88] Referring to Figure 10, a layer 50 of GaN (or, as mentioned above, AlGaN or InGaN) is grown on the free surface of the layer 11 of semi-insulating SiC. The thickness of layer 50 is typically comprised between 1 and 2 µm.

[0063]

[89] A heterojunction is then formed on layer 50 by epitaxy growing a layer 60 of a III-N alloy different from that of layer 50, as shown in Figure 11 .

[0064]

[90] It is then possible to continue fabricating a transistor, in particular a HEMT, from this heterojunction using methods known to those skilled in the art, with the channel of the transistor being formed flush with the heterojunction and the source, drain and gate of the transistor being formed above the channel.

[0065]

[91] The resulting structure is particularly advantageous in that it contains a relatively thick layer of semi-insulating SiC, which only needs to be monocrystalline to serve as a seed for the epitaxial growth of the III-N alloy layer, thereby dissipating heat well and limiting RF losses. Furthermore, the second receiver substrate carrying the layer of semi-insulating SiC is in direct contact with said layer, so that the structure does not contain any thermal barriers.

[0066]

[92] Thus, a HEMT or another high-frequency, high-power electronic device fabricated on a layer of II-N alloy formed by epitaxy on such a structure has minimized RF losses and maximized heat dissipation.

[0067] (References)

[93] [1] Comparative study on stress in AlGaN / GaN HEMT structures grown on 6H-SiC, Si and on composite substrates of the 6H-SiC / poly-SiC and Si / poly-SiC, M. Guziewicz et al, Journal of Physics: Conference Series 100 (2008) 040235

Claims

1. A method for producing a substrate for the epitaxial growth of layers of gallium nitride (GaN), aluminum gallium nitride (AlGaN) or indium gallium nitride (InGaN), comprising the following successive steps: Providing a single crystal semi-insulating silicon carbide donor substrate (10); implanting ionic species into said donor substrate (10) to form a weakened region (12) that defines a thin layer (11) of monocrystalline semi-insulating SiC to be transferred; bonding the donor substrate (10) to a first receiver substrate (20) via a bonding layer (21); Separating the donor substrate (10) along the weakened region (12) so as to transfer the thin layer of single-crystal semi-insulating SiC (11) to the first receiver substrate (20); forming an additional layer (13) of semi-insulating SiC on the transferred thin layer (11) of semi-insulating SiC; Bonding said additional layer (13) of semi-insulating SiC to a second receiver substrate (40) having high electrical resistivity; separating the first receiver substrate (20) and removing at least a portion of the bonding layer (21) to expose the transferred layer of single-crystal semi-insulating SiC (11); A method comprising:

2. The difference in thermal expansion coefficient between the first receiver substrate (20) and the donor substrate (10) is 3×10 -6 K -1 2. The method of claim 1, wherein:

3. The method of claim 1 or 2, wherein the first receiver substrate (20) is a SiC substrate having a lower crystalline quality than that of the donor substrate.

4. The method according to any one of claims 1 to 3, wherein the thin layer (11) of monocrystalline semi-insulating SiC transferred to the first receiver substrate (20) has a thickness of less than 1 μm.

5. 5. The method according to claim 1, wherein the bonding layer (21) is formed from a material that is thermally stable during the formation of the layer of semi-insulating SiC (13) and that can be removed from the interface between the transferred layer of monocrystalline semi-insulating SiC (11) and the first receiver substrate (20).

6. The method according to any one of claims 1 to 5, wherein the bonding layer (21) is a layer of silicon nitride or gallium nitride.

7. The method according to any one of the preceding claims, wherein removing at least a portion of the bonding layer (21) comprises chemical etching, laser delamination, and / or application of mechanical stress.

8. A method according to any one of the preceding claims, wherein the additional layer (13) of semi-insulating SiC is formed by simultaneous deposition of silicon, carbon and vanadium.

9. The method according to any one of the preceding claims, wherein the second receiver substrate (40) is a silicon substrate having an electrical resistivity of 100 Ωcm or more.

10. The method according to claim 9, wherein said additional layer (13) of semi-insulating SiC has a thickness comprised between 1 and 5 μm.

11. The method according to any one of claims 1 to 8, wherein the second receiver substrate (40) is a polycrystalline SiC substrate, a diamond substrate, or a polycrystalline AlN substrate.

12. 12. The method of claim 11, wherein the additional layer (13) of semi-insulating SiC has a thickness of less than or equal to 80 μm.

13. The ion species are implanted through the silicon surface (10-Si) of the donor substrate (10), the silicon surface (10-Si) of the donor substrate (10) is bonded to the first receiver substrate (20) such that, after the bonding layer (21) is removed, the silicon surface of the transferred monocrystalline semi-insulating SiC layer (11) is exposed; The method according to any one of claims 1 to 12.

14. The method according to any one of claims 1 to 13, further comprising recycling the segment (10') of the donor substrate separated from the transferred layer (11) for the purpose of forming a new donor substrate.

15. A method for producing a layer of gallium nitride by epitaxy, comprising: Providing a substrate manufactured using the method of any one of claims 1 to 13; epitaxially growing the gallium nitride layer (50) on the silicon surface (11-Si) of the transferred monocrystalline semi-insulating SiC layer (11) of the substrate; A method comprising:

16. The method according to claim 15, wherein said layer (50) of gallium nitride has a thickness comprised between 1 and 2 μm.

17. 1. A method for fabricating a high electron mobility transistor (HEMT), comprising: - epitaxy production of a layer (50) of gallium nitride using a method according to claim 15 or 16; forming a heterojunction on said layer (50) of gallium nitride by epitaxy of a layer of III-N material other than gallium nitride; forming a channel of the transistor at the same level as the heterojunction; forming a source, a drain and a gate of the transistor on the channel; A method comprising:

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