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  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
  • C30B33/06—Joining of crystals
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  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P90/00—Preparation of wafers not covered by a single main group of this subclass, e.g. wafer reinforcement
• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B28/00—Production of homogeneous polycrystalline material with defined structure
  • C30B28/12—Production of homogeneous polycrystalline material with defined structure directly from the gas state
  • C30B28/14—Production of homogeneous polycrystalline material with defined structure directly from the gas state by chemical reaction of reactive gases
• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
  • C30B29/10—Inorganic compounds or compositions
  • C30B29/36—Carbides
• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
  • C30B33/02—Heat treatment
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P10/00—Bonding of wafers, substrates or parts of devices
  • H10P10/12—Bonding of semiconductor wafers or semiconductor substrates to semiconductor wafers or semiconductor substrates
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P10/00—Bonding of wafers, substrates or parts of devices
  • H10P10/12—Bonding of semiconductor wafers or semiconductor substrates to semiconductor wafers or semiconductor substrates
  • H10P10/128—Bonding of semiconductor wafers or semiconductor substrates to semiconductor wafers or semiconductor substrates by direct semiconductor to semiconductor bonding
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
  • H10P14/24—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials using chemical vapour deposition [CVD]
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
  • H10P14/29—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials characterised by the substrates
  • H10P14/2901—Materials
  • H10P14/2902—Materials being Group IVA materials
  • H10P14/2904—Silicon carbide
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
  • H10P14/29—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials characterised by the substrates
  • H10P14/2924—Structures
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
  • H10P14/34—Deposited materials, e.g. layers
  • H10P14/3402—Deposited materials, e.g. layers characterised by the chemical composition
  • H10P14/3404—Deposited materials, e.g. layers characterised by the chemical composition being Group IVA materials
  • H10P14/3408—Silicon carbide
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
  • H10P14/34—Deposited materials, e.g. layers
  • H10P14/3451—Structure
  • H10P14/3452—Microstructure
  • H10P14/3456—Polycrystalline
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
  • H10P14/38—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials characterised by treatments done after the formation of the materials
  • H10P14/3802—Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P90/00—Preparation of wafers not covered by a single main group of this subclass, e.g. wafer reinforcement
  • H10P90/19—Preparing inhomogeneous wafers
  • H10P90/1904—Preparing vertically inhomogeneous wafers

Definitions

• the field of the invention is that of semiconductor materials for microelectronic components.
• the invention relates more particularly to a process for manufacturing a composite structure comprising a thin layer of monocrystalline silicon carbide on a support substrate of polycrystalline silicon carbide.
• SiC Silicon carbide
• Monocrystalline SiC substrates intended for the microelectronics industry nevertheless remain expensive and difficult to supply in large sizes. It is therefore advantageous to use layer transfer solutions to produce composite structures typically comprising a thin monocrystalline SiC layer on a lower cost support substrate.
• a well-known thin film transfer solution is the Smart CutTM process, based on light ion implantation and direct bonding assembly. Such a process makes it possible, for example, to manufacture a composite structure comprising a thin layer of monocrystalline SiC, taken from a donor substrate of monocrystalline SiC, in direct contact with a support substrate of polycrystalline SiC.
• the object of the invention is to propose a technique which overcomes these drawbacks in order to provide a composite structure comprising a thin layer of very high quality single-crystal SiC, in particular in order to improve the performance and reliability of power devices intended to be developed in said thin layer.
• the invention proposes a process for manufacturing a composite structure comprising a thin layer of monocrystalline silicon carbide, SiC, placed on a support substrate of polycrystalline SiC, comprising the following steps:
• the layer of polycrystalline SiC has a polytype identical to that of the support substrate;
• the formation of the layer of polycrystalline SiC comprises a deposition of polycrystalline SiC
• the deposition of polycrystalline SiC is a chemical vapor deposition
• the formation of the polycrystalline SiC layer comprises deposition of an amorphous SiC layer and recrystallization annealing applied to the amorphous SiC layer;
• the layer of polycrystalline SiC deposited on the donor substrate has a thickness of between 10 nm and 10 ⁇ m;
• the bonding layer formed on each of the donor and support substrates is a metallic layer, for example a layer of tungsten or a layer of titanium;
• the bonding layer formed on each of the donor and support substrates is a layer of silicon, carbon or silicon carbide;
• the bonding layer has a melting temperature lower than an annealing temperature applied during the bonding step.
• Figure 1 is a schematic sectional view of a monocrystalline SiC donor substrate
• FIG. 2 is a schematic sectional view of the deposition of a layer of polycrystalline SiC on the surface of the monocrystalline SiC donor substrate;
• FIG. 3 is a schematic sectional view of the formation, by implantation of ionic species, of an embrittlement plane in the donor substrate of FIG. 1 to delimit a thin layer of monocrystalline SiC to be transferred;
• FIG. 4 is a schematic sectional view of the assembly of the donor substrate of FIG. 2 and of a support substrate;
• FIG. 5 is a schematic sectional view of the detachment of the donor substrate along the plane of embrittlement to transfer the thin layer of monocrystalline SiC onto the support substrate.
• the invention relates to a method for manufacturing a composite structure comprising a thin layer of monocrystalline SiC placed on a support substrate of polycrystalline SiC.
• This process comprises the transfer, in accordance with the Smart CutTM process, of the thin layer of single-crystal SiC carbide to the support substrate from a donor substrate, at least a surface portion of which is made of single-crystal SiC.
• the donor substrate can be a bulk single-crystal SiC substrate.
• the donor substrate can be a composite substrate, comprising a surface layer of monocrystalline SiC and at least one other layer of another material.
• the monocrystalline SiC layer preferably has a thickness greater than or equal to 0.5 ⁇ m.
• the bonding interface is created between materials having the same morphology (namely two polycrystalline SiC), instead of the heterogeneous crystalline structures of the prior art (namely a monocrystalline SiC added to polycrystalline SiC ).
• the invention makes it possible not to create a conduction barrier at the bonding interface and to have a contact surface which is not reduced due to the formation of cavities at this interface.
• the method according to the invention begins with the supply of a donor substrate 10 of which at least a surface portion is made of monocrystalline SiC.
• a solid substrate 10 of monocrystalline SiC has been shown.
• the method comprises a step of forming a polycrystalline SiC layer 11 on the donor substrate 10.
• the polycrystalline SiC layer 11 formed on the donor substrate preferably has a thickness between 10 nm and 10 ⁇ m, even more preferably a thickness of less than 50 nm.
• the size of the grains of the polycrystalline SiC layer 11 is preferably less than 30 nm, even more preferably less than 10 nm, which makes it possible to limit the surface roughness of the layer 11 thus deposited.
• Such a reduced grain size also offers the advantage that the conditions for forming the polycrystalline SiC layer 11 can approach those of an amorphous SiC layer, the layer 11 formed thus being able to be a mixture of grains of small size and a high proportion of amorphous SiC without this harming the effects of the invention.
• the formation of the polycrystalline SiC layer 11 is carried out in such a way as to give it the same polytype as that of the support substrate 20, generally a type 3C polytype.
• the layer of polycrystalline SiC is formed by depositing polycrystalline SiC.
• a deposition of a layer of polycrystalline SiC can be chemical vapor deposition (for example of the EBPVD type for “Electron Beam Physical Vapor Deposition”) or chemical vapor deposition (for example of the DLI-CVD type for “Direct Liquid Injection Chemical Vapor Deposition”).
• the deposition of the polycrystalline SiC layer is carried out at a temperature below 1000°C, preferably below 900°C, even more preferably below 850°C. This embodiment proves particularly advantageous when the deposition of the polycrystalline SiC layer 11 is carried out after the implantation of ionic species described below to form an embrittlement plane in the donor substrate.
• This relatively low temperature in fact makes it possible to limit the growth of the cavities present in the weakening plane, growth which in the absence of a stiffening effect brought to the donor substrate results in the deformation of the layer directly above the cavities and the appearance of the blistering phenomenon.
• the formation of the layer of polycrystalline SiC comprises first of all the deposition of an amorphous SiC layer (in whole or in part) followed by recrystallization annealing, typically at a temperature above 1100° C., transforming the amorphous SiC layer into a polycrystal constituting the polycrystalline SiC layer 11.
• the formation of the polycrystalline SiC layer 11 is accompanied by the formation of a bonding layer on the polycrystalline SiC layer 11 and on the support substrate respectively, for example a layer of silicon, carbon , silicon carbide or even a metal layer, for example a layer of tungsten or titanium.
• the bonding layers can be formed using the physical vapor deposition (PVD) process using argon or an argon/nitrogen or argon/propane mixture as the target ablation gas.
• the bonding layers preferably have a melting temperature lower than an annealing temperature applied during the bonding step.
• silicon or titanium bonding layers are chosen when annealing at a temperature of the order of 1700° C./1800° C. is applied during the bonding step.
• the method further comprises, before or after the formation of the polycrystalline SiC layer 11, an implantation of ionic species in the substrate donor 10 so as to form an embrittlement plane 13 delimiting a thin layer of monocrystalline SiC to be transferred 12.
• the implantation is carried out after the deposition of the layer of polycrystalline SiC 11.
• the implanted species typically include hydrogen and/or helium.
• a person skilled in the art is able to define the energy and the implantation dose required.
• the implantation is carried out so as to form the weakening plane in the superficial layer of monocrystalline SiC of said donor substrate.
• the thin layer 12 of monocrystalline SiC has a thickness of less than 1 ⁇ m.
• a thickness is indeed accessible on an industrial scale with the Smart CutTM process.
• the implantation devices available in industrial manufacturing lines make it possible to achieve such an implantation depth.
• the method comprises, after said implantation and said formation, the bonding of the donor substrate and of the support substrate.
• Bonding is direct bonding without an intermediate electrically insulating layer, obtained by molecular adhesion of the surfaces brought into contact. Bonding is typically carried out at room temperature. It is preferably carried out under vacuum.
• the polycrystalline SiC layer 11 previously formed on the donor substrate is at the bonding interface.
• layer situated at the bonding interface is meant a layer situated on the side of the face of the donor substrate which is bonded to the support substrate but does not necessarily involve direct contact between said layer and the support substrate.
• said layer can be bonded directly to the support substrate or be covered with a bonding layer such as that mentioned previously by means of which the bonding takes place.
• Direct contact bonding of polycrystalline layers has the advantage of physically separating the interface between the monocrystalline SiC and the polycrystalline SiC from the bonding interface.
• This bonding is typically preceded by operations for preparing the surfaces to be bonded, for example here the two polycrystalline SiC surfaces, such as for example fine polishing, wet or dry cleaning, surface activation, etc.
• the method may comprise thinning and/or polishing the surface of the layer of polycrystalline SiC 11 intended to be at the bonding interface during bonding and/or of the surface of the support substrate 20 intended to be at the bonding interface during bonding.
• the method then comprises the detachment of the donor substrate 10 along the weakening plane 13 so as to transfer the layer of polycrystalline SiC 11 and the thin layer of monocrystalline SiC 12 onto the support substrate 10.
• this detachment can be caused by a heat treatment, a mechanical action, or a combination of these means.
• the remainder 10' of the donor substrate is preferably recycled with a view to another use.
• One or more finishing operations can then be applied to the transferred monocrystalline SiC layer 12. It is for example possible to carry out smoothing, cleaning or even polishing, for example chemical-mechanical polishing (CMP, acronym for the English -Saxon “Chemical Mechanical Polishing”) or fine grinding (known as “Fine Grinding”, which makes it possible to overcome preferential chemical attacks on a particular grain orientation), to remove defects linked to the implantation of ionic species and reducing the roughness of the transferred monocrystalline SiC layer 12.
• CMP chemical-mechanical polishing
• Fine Grinding fine grinding

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• 2021
  • 2021-10-05 FR FR2110520A patent/FR3127843B1/fr active Active
• 2022
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