Abstract: A process for manufacturing a two-dimensional film of a group IV material having a hexagonal crystalline structure, in particular, graphene, comprises formation of a growth substrate, comprising the transfer of a single-crystal metal film suitable for the growth of the two-dimensional film on a support substrate, and epitaxial growth of the two-dimensional film on the metal film of the substrate.

Abstract: A process for manufacturing a two-dimensional film of a group IV material having a hexagonal crystalline structure, in particular, graphene, comprises formation of a growth substrate, comprising the transfer of a single-crystal metal film suitable for the growth of the two-dimensional film on a support substrate, and epitaxial growth of the two-dimensional film on the metal film of the substrate.

Abstract: A composite substrate includes a final substrate, and a piezoelectric material directly molecularly bonded to the final substrate at a first interface. The piezoelectric material comprises an epitaxial layer, but does not comprise a seed layer. Additional composite substrates include a final substrate, and a piezoelectric material directly molecularly bonded to the final substrate at a first interface. The piezoelectric material comprises an epitaxial layer. The composite substrate further includes a seed layer on which the piezoelectric material has been epitaxially grown. The seed layer is disposed on a side of the epitaxial layer opposite the final substrate. An acoustic wave device comprises such a composite substrate with at least one electrode on a surface of the piezoelectric layer opposite the substrate.

Abstract: A method for manufacturing a film, notably monocrystalline, on a flexible sheet, comprises the following steps: providing a donor substrate, forming an embrittlement zone in the donor substrate so as to delimit the film, forming the flexible sheet by deposition over the surface of the film, and detaching the donor substrate along the embrittlement zone so as to transfer the film onto the flexible sheet.

Abstract: A method for manufacturing a monocrystalline piezoelectric material layer includes providing a donor substrate made of the piezoelectric material, providing a receiving substrate, transferring a so-called “seed layer” of the donor substrate onto the receiving substrate, and using epitaxy of the piezoelectric material on the seed layer until the desired thickness for the monocrystalline piezoelectric layer is obtained.

Abstract: A method for manufacturing a film, notably monocrystalline, on a flexible sheet, comprises the following steps: providing a donor substrate, forming an embrittlement zone in the donor substrate so as to delimit the film, forming the flexible sheet by deposition over the surface of the film, and detaching the donor substrate along the embrittlement zone so as to transfer the film onto the flexible sheet.

Abstract: A method for separating a removable composite structure using a light flux includes supplying the removable composite structure, which successively comprises: a substrate that is transparent to the light flux; an optically absorbent layer for at least partially absorbing a light flux; a sacrificial layer adapted to dissociate subject to the application of a temperature higher than a dissociation temperature and made of a material different from that of the optically absorbent layer; and at least one layer to be separated. The method further includes applying a light flux through the substrate, the light flux being at least partly absorbed by the optically absorbent layer, so as to heat the optically absorbent layer; heating the sacrificial layer by thermal conduction from the optically absorbent layer, up to a temperature that is greater than or equal to the dissociation temperature; and dissociating the sacrificial layer under the effect of the heating.

Abstract: A method for adjusting the stress state of a piezoelectric film having a first stress state at room temperature includes a step of forming an assembly including a carrier having a thermal expansion coefficient, a compliant layer placed on the carrier, and the piezoelectric film placed on the compliant layer, the piezoelectric film having a thermal expansion coefficient different from that of the carrier. The method also includes a step of heat treating the assembly, in which the assembly is heated to a treatment temperature above the glass transition temperature of the compliant layer. The present disclosure also relates to a process for fabricating an acoustic wave device comprising the piezoelectric layer the stress state of which was adjusted as described herein.

Abstract: A method for manufacturing a film on a support having a non-flat surface comprises: providing a donor substrate having a non-flat surface, forming an embrittlement zone in the donor substrate so as to delimit the film to be transferred, forming the support by deposition on the non-flat surface of the film to be transferred, and detaching the donor substrate along the embrittlement zone so as to transfer the film onto the support.

Abstract: A method for producing a composite silicon carbide structure comprises: providing an initial substrate of monocrystalline silicon carbide; depositing an intermediate layer of polycrystalline silicon carbide at a temperature higher than 1000° C. on the initial substrate, the intermediate layer having a thickness greater than or equal to 1.5 microns; implanting light ionic species through the intermediate layer to form a buried brittle plane in the initial substrate, delimiting the thin layer between the buried brittle plane and the intermediate layer, and depositing an additional layer of polycrystalline silicon carbide at a temperature higher than 1000° C. on the intermediate layer, the intermediate layer and the additional layer forming a carrier substrate, and separating the buried brittle plane during the deposition of the additional layer.

Abstract: A method for manufacturing a film on a support having a non-flat surface comprises: providing a donor substrate having a non-flat surface, forming an embrittlement zone in the donor substrate so as to delimit the film to be transferred, forming the support by deposition on the non-flat surface of the film to be transferred, and detaching the donor substrate along the embrittlement zone, so as to transfer the film onto the support.

Abstract: A structure that can be used to manufacture at least one active layer made of a III-V material thereon includes a substrate comprising a carrier having a main face, a dielectric layer located on the main face of the carrier, and a plurality of single-crystal semiconductor islands located directly on the dielectric layer. The islands have an upper surface in order to serve as a seed surface for the growth of the active layer. The structure further comprises a seed layer located between the single-crystal semiconductor islands, directly on the portion of the dielectric layer that is not covered by the islands, without masking the upper surface of the islands, so that the dielectric layer is not exposed to the external environment.

Abstract: A process for fabricating a growth substrate comprises preparing a donor substrate by forming a crystalline semiconductor surface layer on a seed layer of a carrier. This preparation comprises forming the surface layer as a plurality of alternations of an InGaN primary layer and of an AlGaN secondary layer, the indium concentration and the thickness of the primary layers and the aluminum concentration and the thickness of the secondary layers being selected so that a homogeneous AlInGaN layer that is equivalent, in terms of concentration of aluminum and indium-, to the surface layer has a natural lattice parameter different from the lattice parameter of the seed layer.

Abstract: A method of manufacturing a monocrystalline layer comprises the following successive steps: providing a donor substrate comprising a piezoelectric material of composition ABO3, where A consists of at least one element from among Li, Na, K, H, Ca; and B consists of at least one element from among Nb, Ta, Sb, V; providing a receiver substrate, transferring a layer called the “seed layer” from the donor substrate on to the receiver substrate, such that the seed layer is at the bonding interface, followed by thinning of the donor substrate layer; and growing a monocrystalline layer of composition A?B?O3 on piezoelectric material ABO3 of the seed layer, where A? consists of a least one of the following elements Li, Na, K, H; B? consists of a least one of the following elements Nb, Ta, Sb, V; and A? is different from A or B? is different from B.

Abstract: A method for manufacturing a plurality of crystalline semiconductor islands having a variety of lattice parameters includes the following steps: providing a relaxation substrate that comprises a medium, a flow layer disposed on the medium and, a plurality of strained crystalline semiconductor islands having an initial lattice parameter located on the flow layer, a first group of islands having a first lattice parameter and a second group of islands having a second lattice parameter that is different from the first; and heat treating the relaxation substrate at a relaxation temperature greater than or equal to the glass transition temperature of the flow layer to cause differentiated lateral expansion of the islands of the first and second group. The lattice parameter of the relaxed islands of the first group and the relaxed islands of the second group then have different values.

Abstract: A method of manufacturing a monocrystalline layer, comprises the following successive steps: providing a donor substrate comprising a piezoelectric material of composition ABO3, where A consists of at least one element from among Li, Na, K, H, Ca; and B consists of at least one element from among Nb, Ta, Sb, V; providing a receiver substrate, transferring a layer called the “seed layer” from the donor substrate on to the receiver substrate, such that the seed layer is at the bonding interface, followed by thinning of the donor substrate layer; and growing a monocrystalline layer of composition A?B?O3 on piezoelectric material ABO3 of the seed layer where A? consists of a least one of the following elements Li, Na, K, H; B? consists of a least one of the following elements Nb, Ta, Sb, V; and A? is different from A or B? is different from B.

Abstract: A method for manufacturing a plurality of crystalline semiconductor islands having different lattice parameters includes providing a relaxation substrate comprising a support and a flow layer on the support that includes first and second groups of blocks having different viscosities at a relaxation temperature. The relaxation substrate also comprises a plurality of strained crystalline semiconductor islands on the flow layer, the islands of a first group being located on the first group of blocks and islands of a second group being located on the second group of blocks. The relaxation substrate is then heat treated at a relaxation temperature higher than or equal to the glass transition temperature of at least one block of the flow layer to cause differentiated lateral expansion of the first and second groups of islands such that the first and second groups of relaxed islands then have different lattice parameters.

Abstract: A growth substrate for forming optoelectronic devices comprises a growth medium and, arranged on the growth medium, a first group of crystalline semiconductor islands having a first lattice parameter and a second group of crystalline semiconductor islands having a second lattice parameter that is different from the first. Methods may be used to manufacture such growth substrates. The methods may be used to provide a monolithic micro-panel or light-emitting diodes or a micro-display screen.

Abstract: A method for separating a removable composite structure using a light flux includes supplying the removable composite structure, which successively comprises: a substrate that is transparent to the light flux; an optically absorbent layer for at least partially absorbing a light flux; a sacrificial layer adapted to dissociate subject to the application of a temperature higher than a dissociation temperature and made of a material different from that of the optically absorbent layer; and at least one layer to be separated. The method further includes applying a light flux through the substrate, the light flux being at least partly absorbed by the optically absorbent layer, so as to heat the optically absorbent layer; heating the sacrificial layer by thermal conduction from the optically absorbent layer, up to a temperature that is greater than or equal to the dissociation temperature; and dissociating the sacrificial layer under the effect of the heating.

Abstract: A method for manufacturing film, notably monocrystalline, on a flexible sheet, comprises the following steps: providing a donor substrate, forming an embrittlement zone in the donor substrate so as to delimit film, forming the flexible sheet by deposition over the surface of the film, and detaching the donor substrate along the embrittlement zone so as to transfer the film onto the flexible sheet.