Method for producing a monocrystalline diamond plate, monocrystalline diamond plate and monocrystalline diamond wafer of large size

Abstract

The invention relates to a method (100) for producing a monocrystalline diamond plate from a plurality of monocrystalline diamond seeds (10, 11, 12, 13) which comprise a growth surface, the growth surface comprising a terraced structure, the terraced structure having a plurality of crystallographically oriented faces (OC1, OC2), the crystallographically oriented faces (OC1, OC2) comprising families of {100\} planes or families of {100\} and {113} planes, the method comprising the steps of: - providing (110) monocrystalline diamond seeds (10, 11, 12, 13); - positioning (130) the monocrystalline diamond seeds (10, 11, 12, 13) so as to form a mosaic; - lateral epitaxial growth (140) of the terraced structure according to the crystallographic orientation (OC2).

Description

Description TITLE: METHOD FOR PRODUCING MONOCRYSTALLINE DIAMOND PLATE, MONOCRYSTALLINE DIAMOND PLATE, AND LARGE-SIZE MONOCRYSTALLINE DIAMOND WAFER Technical field

[0001] The invention relates to the field of diamond manufacturing, more specifically large-sized monocrystalline diamond. Prior art

[0002] Below we describe the known prior art from which the invention was developed.

[0003] Diamond is a material with particularly valuable physical properties in many fields. In particular, diamond has unparalleled properties as a semiconductor material, such as high thermal conductivity, high electron / hole mobility, high dielectric breakdown electric field strength, low dielectric loss and broad band structure, radiation resistance, high chemical stability, and excellent optical properties.

[0004] Single-crystal diamond remains one of the most promising materials for the preparation of high-power, high-frequency, high-temperature, voltage-resistant, and quantum optoelectronic devices.

[0005] In particular, in order to put diamond into practice as a semiconductor material, a wafer made of single-crystal diamond having a large surface area and high homogeneity may be required for certain applications.

[0006] To enable the formation of monocrystalline diamond wafers with increasingly large sizes, several growth methods have emerged, among them, the processes for manufacturing monocrystalline diamond wafers by epitaxial growth in step flow have made it possible to obtain good quality monocrystalline diamond wafers.

[0007] Generally, to produce a large-sized single-crystal diamond plate, a plurality of single-crystal diamond seeds are arranged side by side to form a mosaic and undergo epitaxial growth by plasma-enhanced chemical vapor deposition. During epitaxial growth, joints between the seeds are formed. The surface of the grown single-crystal diamond must then be polished to a smooth surface before it can be used as a single-crystal diamond plate for growing a single-crystal epitaxial layer.

[0008] The main technical difficulty is related to the formation of junctions between the seeds, with few or no crystal defects such as dislocations, twins, a modification of the direction of propagation of the wavefront. Indeed, the larger the size of the monocrystalline diamond plate, the greater the number of seeds needed to form it and the higher the risk of crystal defects appearing in the junctions.

[0009] The presence of these crystal defects is critical because, in addition to impacting the quality of the monocrystalline diamond produced, crystal defects also have an impact during the polishing and cutting phases of the epitaxial layer formed on the growth surface. This makes the monocrystalline junctions more fragile and can break more easily. In addition, stresses, which are often responsible for these crystal defects, can also generate fractures during the growth of the epitaxial layer.

[0010] Solutions aimed at partially solving the problems mentioned above have emerged, in particular document No. WO2019139147 relates to a method for producing a single-crystal substrate for a semiconductor formed on a large single-crystal diamond plate. The proposed solution makes it possible to limit the risk of destruction of the single-crystal diamond plate after cutting. For this, it is proposed to use four single-crystal diamond seeds, which have a crystallographic orientation of the {100} family, measuring 10 mm by 10 mm, linked so as to form a mosaic. A plate, formed by the single-crystal diamond seeds, is recovered by a removal step using a "lift-off" process, according to English terminology, i.e. by removing a sacrificial material.As a result, the process of cutting and polishing the developed diamond plate is no longer necessary, thus limiting the risk of damage to the plates during the polishing and cutting phases.

[0011] Another solution described in document No. CN114150376 proposes a method of splicing and growing a large monocrystalline diamond, having a high crystal quality at the splice junctions formed during the growth process of single crystal diamond seeds. For this, starting from a single crystal diamond seed with a crystallographic orientation of the {100} family, a single crystal diamond epitaxial layer is grown on the surface of the seed by chemical vapor deposition. The epitaxial layer is recovered by laser cutting. This step is repeated to obtain a plurality of epitaxial layers with strictly identical crystal orientations. The epitaxial layers are polished to reduce their height difference. The step flow growth direction on the surface of the epitaxial layers is then determined and the epitaxial layers are arranged parallel to the step flow growth direction and then used as seeds for the growth of a single crystal diamond epitaxial layer by chemical vapor deposition.A large monocrystalline diamond epitaxial wafer is thus obtained.

[0012] Although obtaining thick layers of diamond by plasma-enhanced chemical vapor deposition from crystallographically oriented seeds of the {100} family also allows obtaining monocrystalline diamond mosaics with good quality junctions, these methods do not allow producing monocrystalline diamond plates of sufficient size for the formation of substrates for electronic applications. In addition, the solutions proposed in the state of the art involve the application of rather restricted growth conditions imposing a relatively low growth rate and preventing the incorporation of impurities by doping which would modify the properties of the monocrystalline diamond plate.

[0013] Thus, there is a need for the provision of monocrystalline diamond plates which exhibit increased growth surface area and improved quality.

[0014] The invention aims to overcome the drawbacks of the prior art. In particular, the invention aims to provide a method for producing a large monocrystalline diamond plate, said method making it possible to ensure the formation of high-quality junctions, i.e. with few or no crystal defects, between the monocrystalline diamond seeds. Summary of the invention

[0015] The invention aims to overcome these drawbacks. The following presents a simplified summary of selected aspects, embodiments and examples of the present invention for the purpose of providing a basic understanding of the invention. However, this This summary does not constitute an exhaustive overview of all aspects, embodiments and examples of the invention. Its sole purpose is to present selected aspects, embodiments and examples of the invention in a concise form as an introduction to the more detailed description of aspects, embodiments and examples of the invention which follow the summary.

[0016] The invention relates in particular to a method for producing a monocrystalline diamond plate from a plurality of monocrystalline diamond seeds which comprise a growth surface, said one growth surface comprising a terraced structure, said terraced structure having several crystallographic orientation faces, said crystallographic orientation faces comprising {100} plane families or {100} and {113} plane families, the method comprising the following steps: - provision of single-crystal diamond seeds, each of the seeds being associated with structural characteristics, said structural characteristics comprising at least: - a first value describing an angle giving a direction of propagation of a wave front, - a disorientation angle of the terraced structure greater than or equal to 0° and less than or equal to 10°, - positioning the single-crystal diamond seeds so as to form a mosaic, such that two adjacent single-crystal diamond seeds have first values ​​describing the angles giving the directions of propagation of the wavefronts whose difference is less than or equal to 5°, preferably less than or equal to 1°; and - lateral epitaxial growth of the terraced structure, by chemical vapor deposition assisted, preferably by plasma or hot filament, of a monocrystalline layer.

[0017] This thus makes it possible to use a large number of single-crystal diamond seeds and therefore, compared to the methods of the prior art, to increase the available growth surface of the single-crystal diamond plate from which single-crystal diamond wafers can be generated. In particular, the lateral epitaxial growth of the terraced structure is carried out according to the crystallographic orientation comprising families of {100} and {113} planes, preferably this is the crystallographic orientation forming the heights of the steps of the terraced structure. This lateral epitaxial growth allows the formation of junctions between the seeds.

[0018] Such a method also allows faster growth than that permitted by the methods of the prior art, while maintaining optimal crystalline quality. The method according to the invention also makes it possible to modify the physical characteristics of the monocrystalline diamond or the surface of the monocrystalline diamond by the use of doping gas followed by irradiation, for example with a flow of electrons and in particular the incorporation of NV and NV- or XV and XV centers; X being an element such as nitrogen N or Silicon Si for example.

[0019] The invention further aims to provide a large monocrystalline diamond plate. Such a monocrystalline diamond plate has a larger growth surface than that permitted by prior art methods, and optimal crystal quality with few or no crystal defects.

[0020] As will be shown, the method according to the invention can be effective even when, during the seed positioning step, two adjacent single-crystal diamond seeds have first values ​​describing the angles giving the directions of propagation of the wavefronts whose difference is greater than 0°.

[0021] According to other optional features of the process for producing a monocrystalline diamond plate, the latter may optionally include one or more of the following features, alone or in combination: - wherein the lateral epitaxial growth step is followed by a second vertical epitaxial growth of the terraced structure along the crystallographic orientation of the {100} plane family so as to form a monocrystalline diamond epitaxial layer. In particular, it is the lateral epitaxial growth step along the crystallographic orientation of monocrystalline diamond seeds comprising {100} plane families or monocrystalline diamond seeds comprising {100} and {113} plane families which is followed by the second vertical epitaxial growth. - in which the first value describing an angle giving a direction of propagation of a wavefront of a single-crystal diamond seed corresponds to an angle formed between the direction of propagation of the wavefront and a lateral face of the single-crystal diamond seed. - in which the first value describing an angle giving a direction of propagation of a wavefront of a single-crystal diamond seed corresponds to a vector characteristic of the direction of propagation of a wavefront relative to a lateral face of the single-crystal diamond seed. - a step of calculating, from the first values ​​describing a propagation direction for each single-crystal diamond seed, a second value describing the angle giving the propagation direction of a main wavefront of the plurality of single-crystal diamond seeds and in which during the step of positioning the single-crystal diamond seeds so as to form a mosaic, each single-crystal diamond seed (10, 11, 12, 13) comprises angles giving the propagation directions (D, Du) of the wavefronts (FO, FOn) ranging from -5° to +5° relative to the second value, preferably from -2.5° to +2.5°. - said method comprising a step of surfacing, by lithography or by laser, the crystallographic orientation faces of the single-crystal diamond seeds so that said seeds have angles giving the propagation direction of the wavefronts that are substantially identical. In particular, the surfacing step relates to the single-crystal diamond seeds comprising families of {100} planes or crystallographic orientation faces (OC1, OC2) of the single-crystal diamond seeds (10, 11, 12, 13) comprising families of {100} and {113} planes. Preferably, the surfacing step is carried out by laser. - said method comprising a step of resurfacing by laser or by lithography of the monocrystalline diamond plate after removal of the epitaxial layer of monocrystalline diamond, the resurfacing step comprising: - a removal of a predetermined thickness of the monocrystalline diamond plate, - a formation of a new predetermined terraced structure having crystallographic orientation faces of the single crystal diamond seeds comprising {100} families of planes or crystallographic orientation faces of the single crystal diamond seeds comprising {100} and {113} families of planes. Preferably, the surfacing step is carried out by laser. More preferably, the resurfacing step comprises the formation of a new predetermined terraced structure having crystallographic orientation faces of the single crystal diamond seeds comprising {100} and {113} families of planes. This new terraced structure is preferably produced on the single crystal diamond plate, on the surface created during the removal step. - in which the seeds of the new terraced structure, formed during the laser or lithography resurfacing step, have angles giving the direction of propagation of the wave fronts which are substantially identical. - in which the lateral epitaxial growth of the terraced structure according to the crystallographic orientation of the single-crystal diamond seeds comprises a step of introducing a gas suitable for preventing the development of stresses or the formation of crystal defects, preferably twins and dislocations, at the interface between the nuclei. - wherein the terraced structure comprises macroscopic growth steps. In particular, the terraced structure of the single-crystal diamond seeds may comprise growth steps whose height is, for example, at least 100 nm. This makes it possible to improve the junctions and the properties of the diamond layer produced. In addition, the macroscopic growth terraces may have lengths L , Lu of at least 10 pm. - said method comprising a step of creating “XV-” centers, by doping with a suitable “X” gas followed by electron beam irradiation and annealing. This step is preferably carried out after the lateral epitaxial growth step and / or the vertical epitaxial growth step. - wherein the positioning step further comprises placing a single crystal diamond seed relative to another single crystal diamond seed at a distance of at most 200 pm. - in which the terraced structures of the single-crystal diamond seeds have, relative to each other, a first planar disorientation along a horizontal axis and a second planar disorientation along a vertical axis less than an angle of 3°. - wherein each single crystal diamond seed has a thickness difference of at most 50 pm, preferably at most 30 pm, relative to another adjacent single crystal diamond seed. However, single crystal diamond seeds may have a thickness difference of at least 10 pm, for example at least 20 pm, relative to another adjacent single crystal diamond seed. - in which the single-crystal diamond seeds are positioned in order of increasing thickness according to a propagation direction defined by one of the angles of the wave fronts. Thus, the mosaic may comprise seeds having thickness differences of at least 30 pm, for example at least 50 pm. - in which the single-crystal diamond seeds are positioned in order of decreasing thickness according to a propagation direction defined by one of the angles of the wave fronts.

[0022] According to a second object, the invention relates to a monocrystalline diamond plate comprising a plurality of monocrystalline diamond seeds which comprise a growth surface, said growth surface comprising a terraced structure, said terraced structure having several faces of crystallographic orientation, said crystallographic orientation faces comprising families of {100} planes or families of {100} and {113} planes, a misorientation angle of the terraced structure greater than or equal to 0° and less than or equal to 10°, and single-crystal junctions which connect the single-crystal diamond seeds to each other, the single-crystal junctions having been obtained by: - a step of positioning the single-crystal diamond seeds so as to form a mosaic, such that two adjacent single-crystal diamond seeds have first values ​​describing the angles giving the directions of propagation of the wavefronts, the difference of which is less than or equal to 5°, preferably substantially equal to 0°; and - a step of lateral epitaxial growth of the terraced structure according to the crystallographic orientation, by chemical vapor deposition assisted, preferably by plasma or hot filament, of a monocrystalline layer.

[0023] Similarly, the diamond plate according to the invention exhibits expected properties even when two adjacent monocrystalline diamond seeds exhibit first values ​​describing the angles giving the directions of propagation of the wavefronts whose difference is greater than 0°.

[0024] According to other optional features of the monocrystalline diamond plate, the latter may optionally include one or more of the following features, alone or in combination: - in which at least 15%, preferably at least 50% and even more preferably at least 85%, of the junctions formed between the single-crystal diamond seeds have a Raman peak width value at half-height greater than or equal to 2.5 cm -1 and less than 2.9 cm -1 .

[0025] According to a third object, the invention relates to a monocrystalline diamond wafer formed by removing the monocrystalline diamond epitaxial layer obtained by the method according to the invention.

[0026] According to another aspect, the invention also relates to a monocrystalline diamond having a surface comprising at least a first crystallographic face and a second crystallographic face, said crystallographic faces each being associated with a concentration of "XV-" centers and the concentration of "XV-" centers of the first crystallographic face being greater than the concentration of "XV-" centers of the second crystallographic face. In particular, in the monocrystalline diamond according to the invention, the first crystallographic face of the monocrystalline diamond belongs to the {113} family of planes. As will be described, such a monocrystalline diamond is capable of being obtained by a method according to the invention.

[0027] According to a fourth subject, the invention relates to a use of a monocrystalline diamond plate according to the invention, of a monocrystalline diamond according to the invention, or of a monocrystalline diamond wafer according to the invention for the manufacture of an optical window, of a substrate for a semiconductor or for thermal management, of a substrate for quantum technologies, or of a diamond for jewelry, preferably greater than 5 carats, preferably greater than 15 carats. Brief description of the drawings

[0028] Other characteristics and advantages of the invention will be better understood upon reading the description which follows and with reference to the appended drawings, given for illustrative purposes and in no way limiting.

[0029] [Fig. 1] Figure 1 shows a schematic of a method for manufacturing a monocrystalline diamond plate according to the invention. The steps outlined in dotted lines are optional.

[0030] [Fig. 2] Figure 2 represents a graphic illustration of a cross-section of a single crystal diamond seed viewed from the side.

[0031] [Fig. 3] Figure 3 shows a graphic illustration of a cross-section of a single crystal diamond plate viewed from the side after growth of a single crystal diamond layer.

[0032] [Fig. 4] Figure 4 represents a first graphic illustration of a cross-section of two single-crystal diamond seeds viewed from the side.

[0033] [Fig. 5] Figure 5 shows an illustration of a single crystal diamond seed in a perspective view.

[0034] [Fig. 6] Figure 6 represents a diagram of a single-crystal diamond germ seen from above whose step flow takes place according to OC2, OC2 belonging: a) either to the family of {113} planes, b) or to the {100} family.

[0035] [Fig. 7] Figure 7 shows a diagram of a mosaic comprising nine single-crystal diamond seeds viewed from above.

[0036] [Fig. 8] Figure 8 represents a graphic illustration of four single crystal diamond seeds viewed from above.

[0037] [Fig. 9] Figure 9 represents a second graphic illustration of a cross-section of two single-crystal diamond seeds viewed from the side.

[0038] [Fig. 10] Figure 10 corresponds to a photo of a part of a monocrystalline diamond plate according to the invention seen from above.

[0039] The figures do not necessarily respect the scales, particularly in thickness, and this is for illustration purposes.

[0040] Aspects of the present invention are described with reference to flowcharts and / or block diagrams of methods according to embodiments of the invention.

[0041] In the figures, flowcharts and block diagrams illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and methods according to various embodiments of the present invention. In this regard, each block in the flowcharts or block diagrams may represent a system, device, module, or code, which includes one or more executable instructions for implementing the specified logical function(s). In some implementations, the functions associated with the blocks may appear in a different order than shown in the figures. For example, two blocks shown in succession may, in fact, be implemented substantially simultaneously, or the blocks may sometimes be implemented in reverse order, depending on the functionality involved.Each block of the block diagrams and / or flowchart, and combinations of blocks in the block diagrams and / or flowchart, may be implemented by special hardware systems that perform the specified functions or acts or carry out combinations of special hardware and computer instructions. Description of the embodiments

[0042] Below, we describe a summary of the invention and the associated vocabulary, before presenting the disadvantages of the prior art, and finally showing in more detail how the invention overcomes them.

[0043] In the remainder of the description, the expression "monocrystalline diamond plate" may correspond to at least two monocrystalline diamond seeds connected to each other after initial crystal growth.

[0044] The expression "large size" within the meaning of the invention may correspond to a plate or a wafer having a growth surface greater than 2 cm 2 , preferably greater than 3 cm 2 , preferably greater than 5 cm 2 , even more preferably greater than 10 cm 2 , preferably greater than 20 cm 2 , and preferably greater than 315 cm 2 .

[0045] The term "seed" within the meaning of the invention may correspond to the elements on which the diamond layers or films grow. These are, for the monocrystalline layers, natural diamond monocrystals or those produced by high pressure-high temperature (HPHT) process or produced by CVD process (for chemical vapor deposition or chemical vapor deposition assisted by plasma or by hot filament).

[0046] The term "junction" can refer to a part that physically connects two seeds to each other.

[0047] When the term "family crystallographic orientation face" is used, it generally refers to a family of crystal planes. Crystal planes that have a particular crystal shape whose surface is substantially planar and bounding a crystal, which is conventionally denoted in curly brackets. This includes all variants of position that the crystallographic orientation face can take in a crystal. For example, the family of the {100} family crystallographic orientation face also includes variants, positive and negative, such as the (010) and (001) crystallographic faces; Similarly, the family of the {113} family crystallographic orientation face also includes variants, positive and negative, such as the (131) and (311) crystallographic faces.These crystallographic faces are conventionally defined by three Miller indices noted in parentheses as “(hkl)”, h, k and I being able to be positive or negative integers.

[0048] A "terraced structure" according to the invention may correspond to a stepped structure comprising steps characterized by a first crystallographic orientation and terraces characterized by a second crystallographic orientation, the second crystallographic orientation preferably being different from the first crystallographic orientation. The steps of a terraced structure are substantially linear and parallel to each other, while the terraces are substantially linear and parallel to each other. As an illustrative example, the terraces are formed by crystallographic orientation faces of the {100} plane family and the steps by crystallographic orientation faces of the {113} plane family of the terraced structure. They may, for example, form angles of 154.8° or 107.5° between them.

[0049] The term "growth" within the meaning of the invention may correspond to the step or steps of deposition of carbon in sp3 form of crystalline (monocrystalline) diamond contributing to the production of a layer of monocrystalline diamond. The growth conditions and deposition parameters represent a set of values ​​of the variables: pressure, injected microwave power, total gas flow rate, flow rate of the carbon precursor, flow rate of impurities and dopant, composition of the thermal resistance gas and their flow rate, temperatures of the layer or layers being grown for a given reactor.

[0050] The term "diamond" within the meaning of the invention may correspond to one or more layers of more or less thick monocrystalline diamond, resulting from the deposition of carbon in sp3 form of crystalline (monocrystalline) diamond.

[0051] The expression "diamond layer" within the meaning of the invention may correspond to a layer (or film) of monocrystalline, polycrystalline, nanocrystalline or ultra-nanocrystalline diamond formed after nucleation on a surface of monocrystalline diamond or another material. Within the meaning of the invention, monocrystalline diamond is generally obtained by thickening in height and / or width of a single crystal of diamond stem (or seed) originating from a single crystal of natural diamond or produced by high pressure-high temperature (HPHT) process or produced by CVD (for "chemical vapor deposition" assisted by plasma or by hot filament).

[0052] The term "plasma" within the meaning of the invention may correspond to the production, from an electrical discharge in a gas composed of a mixture, of a generally electrically neutral medium but containing ions and electrons as well as fragments of dissociated gaseous species as well as stable molecules.

[0053] The expression "disorientation of the terraced structure" (noted ô), in the sense of the invention, may correspond to the presence of a disorientation angle characterizing the inclination of the terraced structure, more particularly of a terrace formed by a face of crystallographic orientation, for example of the family of planes {100}, relative to the rear face of a monocrystalline diamond seed.

[0054] The term "substantially" for the purposes of the invention means a value varying by less than 30% relative to the compared value, preferably by less than 20%, even more preferably by less than 10%. When substantially identical is used to compare shapes then the vectorized shape varies by less than 30% relative to the compared vectorized shape, preferably by less than 20%, even more preferably by less than 10%. In particular, when substantially identical is used to compare angles then the angle values ​​are not different by more than 10°, preferably by more than 5°, even more preferably by more than 2° and even more preferably by more than 1°.

[0055] For many industrial applications, large monocrystalline diamond layers (e.g., more than 20 centimeters in diameter) are expected. Many methods have already been proposed for producing large monocrystalline diamond layers. However, monocrystalline diamonds obtained using these methods generally exhibit crystalline defects as the size increases. The applicant has developed a new method for reducing these crystalline defects.

[0056] The applicant proposes to use single crystal diamond seeds which have crystallographic orientation faces of the {100} family of planes and preferably of the {100} and {113} family of planes in order to generate a high quality and large size single crystal diamond plate by taking into consideration the structural characteristics of each seed and positioning them according to a propagation angle of a wave front. This allows the formation of high quality junctions, i.e. with few or no crystal defects between the single crystal diamond seeds.In particular, the invention proposes to carry out a first growth generated by conditions favoring the lateral growth of the crystallographic orientation faces of the {113} family of planes in order to ensure the formation of a monocrystalline layer of optimal quality between the seeds, thus limiting the formation of crystalline defects and the risks of cracking during the growth or cutting of a monocrystalline diamond wafer.

[0057] Thus, as illustrated in Figure 1, the invention relates to a method 100 for producing a large-sized single-crystal diamond plate from a plurality of single-crystal diamond seeds, the method comprises a step 110 for providing single-crystal diamond seeds associated with structural characteristics, a step 130 for positioning the single-crystal diamond seeds, and a step 140 for lateral epitaxial growth.

[0058] A single-crystal diamond seed 10 is shown in Figure 2. The single-crystal diamond seed 10, and more generally the single-crystal diamond seeds 11, 12, 13 according to the invention, comprise at least one face Fsc constituting the growth surface of the crystal which is made up of crystal planes formed by faces of crystallographic orientation OC1 and OC2, respectively the terraces and the steps of the terraced structures. The seed also comprises a rear face FAR, opposite the face Fsc constituting the growth surface of the crystal, on which said seed 10 rests during a growth step. The faces of the terraces OC1 of the growth surface Fsc and the rear face FAR are substantially parallel. However, they form an angle d between them, called the misorientation angle.

[0059] As detailed in Figure 3, the single-crystal diamond seed 10 therefore comprises on the surface a stepped structure or terraced structure which has faces of crystallographic orientation OC1, OC2 of the {100} family of planes or of the {100} and {113} family of planes. As shown in Figure 4, the terraced structure of the single-crystal diamond seeds 10, 11 comprises faces of crystallographic orientations OC1 and OC2 which have a predetermined surface. More particularly, the terraced structures of the single-crystal diamond seeds 10, 11 comprise steps of predetermined width L, Lu and height Hw, Hn. Indeed, as shown in Figure 4, the terraced structures of the seeds 10, 11 of monocrystalline diamond used for the formation of a monocrystalline diamond plate must preferentially have misorientation angles ô 10 substantially identical or at least relatively close, they can for example be between 0° and 10°.

[0060] The angles of disorientation ô 10 are for example at least 0.1°, preferably at least 0.5°, more preferably at least 1°, even more preferably at least 2°. The disorientation angles δ 10 are for example at most 9.9°, preferably at most 9.5°, more preferably at most 9°, even more preferably preferred by at most 8°. Thus, the disorientation angles ô 10 are for example between 0.1° and 9.9°, preferably between 0.5° and 9.5°, more preferably between 1° and 9°, even more preferably between 2° and 8°.

[0061] As mentioned, within the same seed it is possible to observe different misorientation angles. Advantageously, the misorientation angles within the same seed should not be very different. Thus, preferably, a single-crystal diamond seed used in the context of the present invention will have a variance in misorientation angles of at most 10%, more preferably at most 5%, even more preferably at most 1%.

[0062] More particularly, as illustrated in Figures 4 and 5, the terraced structure of the single crystal diamond seeds may comprise macroscopic growth steps, for example having a height Hw, Hn of at least 100 nm and up to 5 pm.

[0063] The terraced structure of the single-crystal diamond seeds may comprise growth steps whose height is, for example, at least 100 nm, preferably at least 200 nm, more preferably at least 500 nm, even more preferably at least 1000 nm. The height of the growth steps is, for example, at most 4.5 pm, preferably at most 4 pm, more preferably at most 3.5 pm, even more preferably at most 3 pm. Thus, the heights of the growth steps are, for example, between 100 nm and 4.5 pm, preferably between 200 nm and 4 pm, more preferably between 500 nm and 3.5 pm, even more preferably between 1000 nm and 3 pm. The heights of the growth steps may vary within a seed. Thus, the above values ​​may correspond to median values ​​observed on a germ.

[0064] Preferably, a single crystal diamond seed used in the context of the present invention will have a variance in the heights of the growth steps of less than 30%, more preferably less than 20%, even more preferably less than 10%.

[0065] Furthermore, macroscopic OC1 growth terraces can have lengths L , Lu ranging from 10 pm to 300 pm.

[0066] The terraced structure of single-crystal diamond seeds may comprise growth terraces whose length is, for example, at least 10 pm, preferably at least 20 pm, more preferably at least 30 pm, even more preferably at least 50 pm. The length of the growth terraces is for example at most 300 pm, preferably at most 250 pm, more preferably at most 200 pm, even more preferably at most 150 pm. Thus, the lengths of the growth terraces are for example between 10 pm and 300 pm, preferably between 20 pm and 250 pm, more preferably between 30 pm and 200 pm, even more preferably between 50 pm and 150 pm. The lengths of the growth terraces can vary. Thus, the above values ​​may correspond to median values ​​observed on a germ.

[0067] Preferably, a single crystal diamond seed used in the present invention will have a variance in the lengths of the growth terraces of less than 30%, more preferably less than 20%, even more preferably less than 10%.

[0068] A method according to the invention thus comprises a step 110 of providing seeds 10, 11, 12, 13 of monocrystalline diamond, each of the seeds being associated with structural characteristics. In the context of the invention, the structural characteristics comprise at least a first value describing an angle giving a direction of propagation Dw of the wavefront FOw.

[0069] Such an angle can be formed by the direction of displacement of the steps or faces of crystallographic orientation OC2 and the x or y axes of the lateral faces FBD of the seed 10 of monocrystalline diamond, oriented as indicated in Figures 5 and 6. The value of the angle D thus makes it possible to define the direction of propagation of the wave front FOw, representing the displacement of the step fronts or faces of crystallographic orientation OC2, which is called Wave Front as presented in Figure 6.

[0070] A method according to the invention may further comprise a step of determining (not shown in the figures) the structural characteristics of each seed 10, 11, 12, 13 of monocrystalline diamond previously mentioned.

[0071] As illustrated in Figure 7, for each of the seeds, a first value describing an angle Dw, Du giving a propagation direction of the wavefront FOw is provided. The angles Dw, Du are defined as they belong to the interval [0, TT / 2]. During diamond growth by microwave plasma-assisted deposition, the wavefronts move at a very specific angle, direction and sense along the terraced structure of each single-crystal diamond seed.

[0072] The structural characteristics also include a misorientation angle 5, of the terraced structure, greater than or equal to 0° and less than or equal to 10° relative to the rear face FAR. Advantageously, the misorientation angle is strictly greater than 0°. In addition, when the misorientation angle is greater than 0° but less than or equal to 10°, growth by step flow mechanism occurs and this makes it possible to limit the appearance of crystalline defects during the growth stages, and more particularly the formation of twins.

[0073] Additionally, the structural characteristics may include the dimensions of the growth steps of the terraced structure, the direction of wavefront propagation and / or the thickness of each single-crystal diamond seed 10, 11, 12, 13.

[0074] To determine the structural characteristics of the seeds 10, 11, 12, 13 of monocrystalline diamond, known techniques such as optical or digital microscopy, electron backscatter diffraction which allows microstructural and crystallographic characterization via a scanning electron microscope can for example be used. This makes it possible to provide information on the structure, crystallographic orientation, phase, or deformation in the material.

[0075] Furthermore, it is possible to measure the crystallographic orientation of the faces of the seeds by electron microscopy techniques in order to provide only the seeds which have faces of the same crystallographic orientation.

[0076] The production method 100 may also comprise a calculation step 120, from the values ​​describing an angle giving the propagation direction Dw, Du, provided for each seed 10, 11, 12, 13 of monocrystalline diamond, of a second value describing the angle giving the propagation direction of the main wavefront FO of the plurality of seeds 10, 11, 12, 13 of monocrystalline diamond.

[0077] By way of non-limiting example, the calculation step 120 can be implemented by a computer or more generally by any type of computing device configured for this.

[0078] In a first embodiment, the production method 100 according to the invention may comprise a surfacing step 115, by lithography or by laser, of the faces of crystallographic orientation OC1, OC2 of the families of planes {100} or of the families of planes {100} and {113} of the seeds 10, 11, 12, 13 of monocrystalline diamond of so that said seeds have angles giving the propagation directions D10, Du of the wave fronts FOw, FOn which are substantially identical. This thus makes it possible to limit the appearance of crystalline defects during the growth stages.

[0079] By way of non-limiting example, the surfacing step 115 may be implemented by a laser, such as a laser guided by a water jet, for example 50 pm in diameter, with a wavelength of 532 nm, a power of 50 W and a frequency of 6 kHz. In particular, the surfacing step 115 may be implemented by a laser having a diameter of at least 10 pm, preferably at least 20 pm, more preferably at least 30 pm and more preferably at least 50 pm in diameter. The surfacing step 115 may be implemented by a laser having a diameter of at most 200 pm, preferably at most 150 pm, more preferably at most 125 pm and more preferably at most 100 pm in diameter.

[0080] The surfacing step 115 can be carried out by scanning the laser over the surface of the monocrystalline diamond plate. The surfacing step 115 can alternatively be implemented by lithography, in particular by the use of a photolithography mask comprising patterns to be produced on the surface of the diamond. A step of depositing SiC>2 in a PECVD (plasma-assisted chemical vapor deposition) frame and then photosensitive resin precedes the photolithography. Then, a step of etching the SiC>2 deposit and then the diamond in a reactive ion etching frame completes the resurfacing.

[0081] The production method 100 according to the invention further comprises a step 130 of positioning the monocrystalline diamond seeds, so as to form a mosaic. The monocrystalline diamond seeds are positioned so that two adjacent monocrystalline diamond seeds have first values ​​describing the angles giving the propagation directions Dw, Du of the wavefronts FO, FOn, the difference of which is preferably substantially equal to 0°, more preferably equal to 0°.

[0082] The single-crystal diamond seeds are positioned so that two adjacent single-crystal diamond seeds have first values ​​describing the angles giving the propagation directions Dw, Du of the wavefronts FOw, FOn whose difference is at most 5°.

[0083] The single crystal diamond seeds are positioned so that two adjacent single crystal diamond seeds have first values ​​describing the angles giving the directions of propagation Dw, Du of the wavefronts FOw, FOn whose difference is greater than or equal to 0° and less than or equal to 5°.

[0084] The single-crystal diamond seeds can be positioned so that two adjacent single-crystal diamond seeds have first values ​​describing the angles giving the propagation directions D, Du of the wavefronts FOw, FOn whose difference is less than or equal to 4°, preferably less than or equal to 3°, preferentially less than or equal to 2° and even more preferably less than or equal to 1° and even more preferably equal to 0°.

[0085] In one embodiment, the positioning 130 of the monocrystalline diamond seeds can be carried out according to the same direction of propagation of the wavefront FOw, FOn, so as to form a mosaic, each monocrystalline diamond seed 10, 11, 12, 13 comprising an angle giving the direction of propagation Dw, Du, of the wavefront FOw, FOn, the difference of which is greater than or equal to 0° and less than or equal to 5°. relative to the second value describing the angle giving the direction of propagation of the main wavefront FO of the plurality of monocrystalline diamond seeds 10, 11, 12, 13 constituting the mosaic.

[0086] Optionally, as shown in Figure 7, the seeds 10, 11, 12, 13 of monocrystalline diamond may be parallelepipedal in shape, more particularly square in shape, or octahedral or triangular. They may furthermore be positioned offset from each other, so that at least one vertex S of each seed 10, 11, 12, 13 of monocrystalline diamond is positioned opposite one another relative to one side of an adjacent monocrystalline diamond seed. Thus, the vertices S of the seeds are in contact or not and opposite at most two adjacent seeds. This thus makes it possible to limit the generation of mechanical stresses during the growth steps.

[0087] In order to obtain high quality junctions and enable the manufacture of a large single crystal diamond plate, the single crystal diamond seeds may have a thickness difference of at most 50 pm, preferably at most 30 pm, relative to another adjacent single crystal diamond seed.

[0088] In order to further improve the formation of high-quality junctions and enable the fabrication of a large-sized single-crystal diamond plate, the single-crystal diamond seeds can be positioned in order of increasing thickness along a propagation direction defined by one of the angles Dw, Du of the wavefronts FOw, FOn . More particularly, the single-crystal diamond seeds are positioned so as to have an increasing thickness difference with respect to one or more of the adjacent seeds, in the direction of the propagation directions of the wavefronts FOw, FO11 given by their angles Dw Du. As an illustrative example, the single-crystal diamond seeds, which form the mosaic and which have a minimum first thickness E1 can be positioned first in the direction of the propagation directions of their wavefronts, of associated angles D , Du then the single-crystal diamond seeds which have a second increasing thickness E2 of less than 5 pm difference with respect to the first thickness E1 can be positioned adjacent to the single-crystal diamond seeds which have such a first thickness E1.Finally, the single-crystal diamond seeds which have an increasing thickness, for example a third thickness E3 of more than 5 pm and up to 50 pm difference with respect to the adjacent seeds, are positioned next, adjacent to the single-crystal diamond seeds which have a second increasing thickness E2 of less than 5 pm difference with respect to the first thickness E1 in the direction of the propagation direction defined by one of the angles Dw, Du of the wavefronts FOw, FOn. Thus, the difference in thickness between each adjacent single-crystal diamond seed is preferably less than or equal to 30 pm, more preferably less than or equal to 25 pm, even more preferably less than or equal to 20 pm, and for example less than or equal to 15 pm.

[0089] Optionally, the positioning step 130 may further comprise placing a single crystal diamond seed relative to another single crystal diamond seed at a distance R1 of at most 200 pm, preferably at most 150 pm, more preferably at most 100 pm, even more preferably at most 50 pm.

[0090] Still in the invention, the method 100 for producing a large monocrystalline diamond plate comprises a step of depositing a layer of monocrystalline diamond on the mosaic, this deposition step comprises one or more epitaxial growth steps. The step of depositing a layer of monocrystalline diamond on the mosaic may comprise the injection of a gas at predetermined pressure, flow rate and temperature conditions. For this, the mosaic is, for example, positioned in a known type of microwave plasma-assisted deposition reactor, for example under the following conditions: 200 mbar, 21 kW, 2000 seem of H2, 5% CH4, and at a growth temperature ranging from 1000°C to 1060°C. By way of non-limiting example, the microwave plasma-assisted deposition reactor may comprise: - a resonant cavity formed at least in part by the cylindrical internal walls of a reactor enclosure, - a treatment gas supply system capable of supplying treatment gases into the resonant cavity, - a microwave generator configured to generate microwaves with a frequency between 300 MHz and 3000 MHz, - a gas outlet module capable of removing said gases from the resonant cavity, - a wave coupling module capable of transferring microwaves from the microwave generator to the resonant cavity, so as to enable the formation of a homogeneous plasma at the plasma / surface interface, - a growth support present in the resonant cavity, - a surface growth temperature control module.

[0091] In particular, the production method 100 according to the invention comprises a step of lateral epitaxial growth 140 of the terraced structure according to the crystallographic orientation OC2 of the face of families of planes {100} when the seeds comprise families of planes {100} only or of the family of planes {113} when the seeds comprise families of planes {100} and {113}, by plasma-assisted chemical vapor deposition of a monocrystalline layer.

[0092] The lateral epitaxial growth step 140 can be carried out in a known type of plasma-enhanced deposition reactor at predetermined conditions to allow C2 growth along the OC2 crystallographic orientation as shown in Figure 3.

[0093] Preferably, the epitaxial growth step 140 comprises epitaxial growth according to the crystallographic orientation OC2 of the face of the {113} family of planes. Indeed, it allows the formation of monocrystalline junctions 10-1, between two seeds 10, 11 of monocrystalline diamond, of high quality as is presented in the examples.

[0094] The lateral epitaxial growth step 140 may optionally be performed by a means suitable for hot filament assisted chemical vapor deposition.

[0095] As an illustrative example, the growth conditions during the lateral epitaxial growth step 140 may include the generation of a pressure of between 20 hPa and 500 hPa within the resonant cavity, the injection of microwaves at a power of, for example, between 0.5 kW and 100 kW (or more), depending on the type of generator used (frequency used), the injection of gas, for example at a total flow rate of at least 150 standard cm 3 per minute (sccm), the gases comprising for example methane, argon and dihydrogen or a mixture of all or part of these gases, and additives such as oxygen, nitrogen, boron, phosphorus and argon, or halogens and the operation of cooling systems for the enclosure, the substrate to control the temperature of the growth surface(s) in a range preferably from 800°C to 1200°C, the gas injection system and the substrate holder.

[0096] In a particular embodiment of the production method 100 according to the invention, the step of lateral epitaxial growth 140 of the terraced structure according to the crystalline orientation OC2 of the seeds 10, 11, 12, 13 of monocrystalline diamond comprising families of planes {100} or seeds 10, 11, 12, 13 of monocrystalline diamond comprising families of planes {100} and {113}, may comprise a step of introduction 141 of a gas suitable for preventing the development of stresses and the formation of twins at the interface between the seeds 10, 11, 12, 13. Such a gas may for example be introduced by a gas supply system to allow a supply of nitrogen into the resonant cavity, for example at a concentration of at most 250 ppm of nitrogen, preferably at most 10 ppm nitrogen, preferably not more than 3 ppm nitrogen.The use of nitrogen, at a content of for example at least 1 ppm, for example during the lateral epitaxial growth step 140 makes it possible to limit the development of crystalline defects, in particular twins, and ensures greater crystalline stability.

[0097] In a particular embodiment of the production method according to the invention, the lateral epitaxial growth step 140 may further comprise a step 142 of creating colored centers called “XV-” centers, followed by electron beam irradiation and annealing. For this, the step 142 of creating XV- centers comprises the introduction, by a gas supply system, to allow a supply of “X” doping gas, such as, by way of non-limiting examples, nitrogen or silicon, into the resonant cavity, for example at a concentration of 10 ppm to 1000 ppm of nitrogen. The use of such so-called doping gases makes it possible to modify the properties of the synthesized diamond. This can, for example, modify its optical, electronic and quantum properties. Advantageously, the creation step 142 can be carried out during lateral epitaxial growth of the terraced structure according to the crystallographic orientation OC2 of the face of the {113} family of planes.

[0098] In another particular embodiment of the production method according to the invention, this may comprise a second step of lateral epitaxial growth further comprising the creation 142 of “XV-” centers as described previously. Preferably, this step of creation 142 of “XV-” centers will be carried out after a surfacing step.

[0099] In a production method 100 according to the invention, the lateral epitaxial growth step 140 of the terraced structure which allowed the formation of the junctions by lateral displacement of the OC2 planes, can be followed by a second vertical epitaxial growth 150 according to the crystallographic orientation OC1 of the face of the family of planes {100} of the seeds 10, 11, 12, 13 of monocrystalline diamond comprising families of planes {100} or seeds 10, 11, 12, 13 of monocrystalline diamond comprising families of planes {100} and {113}, which allows vertical growth so as to form an epitaxial layer 10-2 of monocrystalline diamond.The vertical growth step 150 of the terraced structure along the OC1 crystallographic orientation of the {100} plane family can be implemented in a microwave plasma-assisted deposition reactor as described previously, at predetermined conditions to promote C1 growth along the OC1 crystallographic orientation as shown in Figure 3. The step flow growth mechanism (movement of wavefronts from one seed to another) allows the formation of high quality 10-1 single-crystal junctions, between two single-crystal diamond seeds 10, 11.The vertical epitaxial growth step 150 along the OC1 crystallographic orientation of the face of the {100} plane family also takes place according to this mechanism, and the crystal grows along C1 (vertically) and along C2 (laterally) although the growth conditions are adapted to favor more marked vertical or lateral growth along the OC1 and OC2 orientations.

[0100] When the production method 100 according to the invention comprises a second vertical epitaxial growth 150, it may further require a step 160 of removing the epitaxial layer 10-2 of monocrystalline diamond. The removal step 160 may consist of cutting with a laser of known type or by another method, for example of the lift-off type.

[0101] As already mentioned, one of the objectives of the invention is to produce a plate 1 of monocrystalline diamond which has high quality junctions. Another objective of the invention is to allow the reuse of said plate 1 of monocrystalline diamond once produced. For this, the step 160 of removing the epitaxial layer 10-2 of monocrystalline diamond can be followed by a step 115' of resurfacing by laser or by lithography of the single-crystal diamond plate. The 115' resurfacing step by laser or lithography includes: - a removal of a predetermined thickness of the monocrystalline diamond plate, - optionally, a polishing step, - a formation of a new predetermined terraced structure having faces of crystallographic orientation OC1, OC2 of the seeds 10, 11, 12, 13 of monocrystalline diamond comprising families of planes {100} or faces of crystallographic orientation OC1, OC2 of the seeds 10, 11, 12, 13 of monocrystalline diamond comprising families of planes {100} and {113} or else faces of crystallographic orientation OC1, OC2 of the seeds 10, 11, 12, 13 of monocrystalline diamond comprising families of planes {100} and {110}.

[0102] In order to maintain a similar quality for the formation of the single-crystal junctions, the faces of crystal orientations OC1, OC2 of the {100} plane families or of the {100} and {113} plane families of the new terraced structure are formed according to the angles giving the propagation directions Dw, Du of the wavefronts FO10, FO11 of the single-crystal diamond seeds of the positioning step 130.

[0103] Thus, the seeds of the new terraced structure, formed during the resurfacing step 115' by laser or by lithography, have an angle giving the direction of propagation D, Du of the wavefront FOw, FOn which is substantially identical.

[0104] As shown in Figures 8 and 9, the single-crystal diamond seeds of the production method 100 according to the invention may comprise terraced structures which have, relative to each other, a planar disorientation along a horizontal axis Y1 and a planar disorientation along a vertical axis Z1.

[0105] The planar disorientations will have an angle Ow, an, Pw, Pu of planar disorientation along a horizontal axis Y1 and / or a vertical axis Z1, respectively with respect to the lateral face FBD and / or the face FAR constituting the rear surface of the crystal which will be for example less than 3°, preferably less than 2.5°, more preferably less than 2°, even more preferably equal to 0°. The planar disorientations will have an angle a, an of planar disorientation along a horizontal axis Y1 and / or a vertical axis Z1, respectively with respect to the lateral face FBD and / or the face FAR constituting the rear surface of the crystal which will be for example greater than or equal to 0°, preferably greater than 0.1°, more preferably greater than 0.2°, even more preferably greater than 0.5°. The planar disorientations will have an angle a, an of planar disorientation along a horizontal axis Y1 and / or a vertical axis Z1, respectively with respect to the lateral face FBD and / or the face FAR constituting the rear surface of the crystal which will be for example between 0° and 3°, preferably between 0° and 2.5°, more preferably between 0° and 1°, even more preferably between 0° and 0.5° (limits included). The planar disorientations may alternatively have an angle of planar disorientation along a horizontal axis Y1 and / or a vertical axis Z1, respectively with respect to the lateral face FBD and / or the face FAR constituting the rear surface of the crystal of between 0.1° and 3°, preferably between 0.2° and 2.5°, more preferably between 0.5° and 1°.

[0106] The planar misorientation angles may vary within a mosaic. Thus, the above values ​​of planar misorientation angles may correspond to median values ​​observed on a seed. Preferably, a mosaic used in the context of the present invention will have a variance of the planar misorientation angles of less than 30%, more preferably less than 20%, even more preferably less than 10% relative to the median of the planar misorientation angle values.

[0107] According to a second object, the invention relates to a plate 1 of monocrystalline diamond, preferably of large size, capable of being obtained by the present invention. The plate 1 of monocrystalline diamond can advantageously be obtained by a production method 100 according to the invention.

[0108] In particular, the invention relates to a plate 1 of monocrystalline diamond, preferably of large size, which comprises a growth surface, said growth surface comprising a terraced structure, said terraced structure having several faces of crystallographic orientation OC1, OC2, said faces of crystallographic orientation OC1, OC2 comprising families of planes {100} or families of planes {100} and {113}, a misorientation angle (θ) of the terraced structure greater than or equal to 0° and less than or equal to 10°, and monocrystalline junctions which connect the seeds 10, 11, 12, 13 of monocrystalline diamond to each other, the monocrystalline junctions having been obtained by: - a step of positioning the single-crystal diamond seeds so as to form a mosaic, so that two adjacent single-crystal diamond seeds 10, 11, 12, 13 have first values ​​describing the angles giving the directions of propagation Dw, Du of wavefronts FO, FOn whose difference is greater than or equal to 0° and less than or equal to 5°, preferably less than or equal to 1°, - a step of lateral epitaxial growth of the terraced structure according to the OC2 crystallographic orientation, by chemical vapor deposition assisted, preferably by plasma or hot filament, of a monocrystalline layer.

[0109] A monocrystalline diamond plate 1 according to the invention comprises junctions, formed between the monocrystalline diamond seeds, in which at least 15% of the junctions, preferably at least 50%, even more preferably at least 85% have a Raman peak width value at half-height ranging from 2.4 cm -1 at 2.9 cm -1 , preferably substantially equal to 2.5 cm -1 .

[0110] A plate 1 of monocrystalline diamond according to the invention thus allows the formation of an epitaxial layer 10-2 of monocrystalline diamond by growth according to the crystallographic orientation OC1 of the {100} family of planes. The quality of the junctions of the plate 1 of monocrystalline diamond allows, when removing the epitaxial layer 10- 2, the obtaining of a large monocrystalline diamond wafer particularly suitable for use in the manufacture of an optical window, a semiconductor substrate, a substrate for thermal management, a substrate suitable for quantum technologies, or a jewelry diamond at least greater than 5 carats, preferably greater than 10 carats, preferably greater than 15 carats. Alternatively, the plate 1 of monocrystalline diamond according to the invention may be directly used in the applications mentioned above.

[0111] The invention makes it possible to form a monocrystalline diamond, whether a plate or a wafer, having a surface comprising at least a first crystallographic face and a second crystallographic face, said crystallographic faces each being associated with a concentration in “XV-” centers and the concentration in “XV-” centers of the first crystallographic face being greater than the concentration in “XV-” centers of the second crystallographic face. Such a monocrystalline diamond has particularly expected properties. Indeed, while many seek to homogenize the concentration in “XV” centers on the surface of monocrystalline diamonds, the present invention focuses on “XV-” centers and seeks to create areas of differential concentrations. Furthermore, advantageously, a monocrystalline diamond according to the invention is large.

[0112] Preferably, the concentrations of “XV-” centers of the crystallographic faces are such that the ratio between the concentration of “XV-” centers of the first crystallographic face and the concentration of “XV-” centers of the second crystallographic face is greater than 1.1; preferably greater than 2; more preferably greater than 5 and even more preferably greater than 10. The concentration of “XV-” centers can be measured using several techniques, for example using photoluminescence measurements with a confocal microscope coupled with a Hanbury-Brown and Twiss interferometer (ref. Thesis L. Rondin, HAL Id: tel-00824468, 2013).

[0113] The concentration of “XV-” centers on the first crystallographic face is, for example, greater than 3 ppm, preferably greater than 5 ppm and even more preferably more than 10 ppm.

[0114] Thus, the monocrystalline diamond plate or wafer may have bands enriched in “XV-” centers compared to the adjacent monocrystalline diamond zones. Preferably, the monocrystalline diamond may have at least two bands at least 10 μm high having a concentration in “XV-” centers higher than the adjacent monocrystalline diamond zones.

[0115] These bands may correspond to the first crystallographic face. Preferably, the monocrystalline diamond wafer may comprise at least two bands of at least 10 pm in height corresponding to the first crystallographic face.

[0116] Even if the crystallographic faces may have the same crystallographic orientation (e.g. {100} plane family), preferably, the crystallographic faces will have crystallographic orientations of different plane families. Also, the monocrystalline diamond wafer may have bands corresponding to a crystallographic orientation face of a first plane family and bands corresponding to a crystallographic orientation face of a second plane family, different from the first plane family.

[0117] Preferably, the monocrystalline diamond may comprise at least two bands corresponding to crystallographic faces having a crystallographic orientation of a first family of planes and at least two bands corresponding to crystallographic faces having a crystallographic orientation of a second family of planes, different from the first family of planes.

[0118] Furthermore, advantageously, the first crystallographic face may belong to the {113} or {110} family of planes while the second crystallographic face may belong to the {100} family of planes.

[0119] Thus, monocrystalline diamond may present distinct bands by their concentration in the “XV-” center and / or by the family of planes of the orientation of their crystallographic face.

[0120] Preferably, the invention therefore relates to a monocrystalline diamond, whether a plate or a wafer, having a surface comprising at least a first crystallographic face and a second crystallographic face, said crystallographic faces each being associated with a concentration in “XV-” center and the concentration in “XV-” center of the first crystallographic face being greater than the concentration in “XV-” center of the second crystallographic face.

[0121] Such a monocrystalline diamond may have the properties described above in connection with the method according to the invention, the plate or the wafer. Advantageously, the first crystallographic face of the monocrystalline diamond belongs to the {113} family of planes.

[0122] As illustrated by the examples below, the present invention provides a solution based on the use of a mosaic of selected single-crystal diamond seeds which have particular structural characteristics and are positioned in a particular way. In particular, the seeds are selected and positioned according to the values ​​of the angles giving the direction of propagation of a wavefront. This contributes to the formation of a large single-crystal diamond plate whose junctions are of high quality. Examples

[0123] Formation of the reference monocrystalline diamond plates

[0124] Fifty single-crystal diamond seeds measuring 8 mm by 8 mm were selected to form 32 cm single-crystal diamond plates. 2 The monocrystalline diamond seeds used have the following structural characteristics: - a growth surface which includes a terraced structure which has crystallographic orientation faces of the {100} and {113} plane families, - a disorientation angle of the terraced structure of approximately 3° (with an accuracy of approximately 1°).

[0125] For each of the single-crystal diamond seeds, the value of the angle giving the direction of propagation of the wavefront is provided.

[0126] The various single-crystal diamond plates presented below are formed by plasma-assisted chemical vapor deposition as presented in C. Findeling-Dufour et al., Diamond and Related Materials 4 (1995) 428-434 or in A. Tallaire et al. Growth of large size diamond single crystals by plasma assisted chemical vapor deposition: Recent achievements and remaining challenges I CR Physique 14 (2013) 169-184. Methodology for measuring the quality of single-crystal diamond seed junctions:

[0127] The measurement of the full width at half maximum of the Raman peak of the single crystal diamond plate located at 1332.5 cm -1is performed with a 473 nm wavelength laser with a power of 400 mW with a x100 objective at 298 K. The measurement is performed on the surface of the single-crystal diamond plate, along a line that includes the single-crystal diamond seeds and their junctions or as described in V.G. RALCHENKO, et al.; Thermal Conductivity of Diamond Mosaic Crystals Grown by Chemical VaporDeposition: Thermal Resistance of Junctions; PHYS. REV. APPLIED 16, 014049 (2021).

[0128] Junctions are defined by their quality, which reflects the presence or absence of crystal defects. Three types of junctions are defined in order to qualify the overall quality of the formed monocrystalline diamond plate, namely: - Type 1 junction, characterized by the presence of wavefronts of steps and terraces whose directions may be different from those of adjacent seeds, but also by the presence of crystal defects such as twins and dislocations. This type of junction is characterized by a Raman peak width at half-height greater than 6 cm -1 . - Type 2 junction, characterized by the presence of dislocations only. This type of junction is characterized by a Raman peak width at half-height ranging from 3 cm -1 at 5.9 cm -1 . - Type 3 junction, characterized by the absence of crystal defects, more particularly the absence of twins and dislocations. This type of junction is characterized by a Raman peak width at half-height greater than or equal to 2.5 cm -1 and less than 2.9 cm -1 .

[0129] Table 1 below presents the main characteristics concerning the positioning of the different monocrystalline diamond seeds used for the formation of monocrystalline diamond plates as well as the results of the measurement of the quality of the junctions produced for each reference of monocrystalline diamond plate, namely: - DIAM 01: the adjacent monocrystalline diamond seeds are positioned randomly, the values ​​of the angles giving the propagation directions of the different wave fronts are inscribed in a circle (from 0° to 360°). - DIAM 02: the adjacent monocrystalline diamond seeds are positioned in the same direction of propagation of the wavefront, the difference between the values ​​of the angles giving the directions of propagation of the wavefronts of all the monocrystalline diamond seeds is within an interval of + or - 45°. - DIAM 03: the adjacent monocrystalline diamond seeds are positioned in the same direction of propagation of the wavefront, the difference between the values ​​of the angles giving the direction of propagation of the wavefronts of all the monocrystalline diamond seeds is within an interval of + or -15°. The monocrystalline diamond seeds are positioned in order of decreasing thickness according to the direction of propagation of the wavefront of one of the seeds of the mosaic. - DIAM 04: the adjacent monocrystalline diamond seeds are positioned according to the same direction of propagation of the wavefront, the difference between the values ​​of the angles giving the direction of propagation of the FO wavefronts of all the monocrystalline diamond seeds is within an interval of + or - 15°. The monocrystalline diamond seeds are positioned in order of increasing thickness according to the direction of propagation of the wavefront of one of the seeds of the mosaic. - DIAM 05: the adjacent monocrystalline diamond seeds are positioned in the same direction of propagation of the wavefront, the difference between the values ​​of the angles giving the direction of propagation of the wavefronts of all the monocrystalline diamond seeds is included in the interval [0°; 5°]. [Table 1]

[0130] These results show that the positioning of the single-crystal diamond seeds during the formation of the mosaic is particularly important. Indeed, the results show a very clear improvement in the quality of the junctions of the single-crystal diamond plates when the single-crystal diamond seeds have first values ​​describing the angles giving the directions of propagation of the wavefronts whose difference is less than or equal to 5°. Figure 10 shows a part of the plate referenced DIAM05, it can be observed with the naked eye that the 10-1 junctions between the plates do not have crystalline defects.

[0131] Furthermore, these results show that positioning the single-crystal diamond seeds with increasing or decreasing thickness relative to the wavefront propagation direction improves the quality of the formed junctions.

[0132] The invention may be the subject of numerous variants and applications other than those described above. In particular, unless otherwise indicated, the different structural and functional characteristics of each of the implementations described above should not be considered as combined and / or closely and / or inextricably linked to each other, but on the contrary as simple juxtapositions. Furthermore, the structural and / or functional characteristics of the different embodiments described above may be the subject in whole or in part of any different juxtaposition or any different combination.

Claims

Claims 1. A method of producing (100) a monocrystalline diamond plate from a plurality of monocrystalline diamond seeds (10, 11, 12, 13) which comprise a growth surface, said one growth surface comprising a terraced structure, said terraced structure having a plurality of crystallographic orientation faces (OC1, OC2), said crystallographic orientation faces (OC1, OC2) comprising families of planes {100} or families of planes {100} and {113}, the method comprising the following steps: - supply (110) of seeds (10, 11, 12, 13) of monocrystalline diamond, each of the seeds being associated with structural characteristics, said structural characteristics comprising at least: - a first value describing an angle giving a direction of propagation (Dw, Di 1) of a wave front (FOw, FOn), - a disorientation angle (5) of the terraced structure greater than or equal to 0° and less than or equal to 10°, - positioning (130) of the seeds (10, 11, 12, 13) of monocrystalline diamond so as to form a mosaic, so that two adjacent monocrystalline diamond seeds have first values ​​describing the angles giving the directions of propagation (D, Du) of the wave fronts (FOw, FOn) whose difference is less than or equal to 5°, preferably less than or equal to 1°; and - lateral epitaxial growth (140) of the terraced structure according to the crystallographic orientation (OC2), by chemical vapor deposition assisted, preferably by plasma or hot filament, of a monocrystalline layer.

2. Production method (100) according to claim 1, wherein the step of lateral epitaxial growth (140) according to the crystallographic orientation (OC2) is followed by a second vertical epitaxial growth (150) of the terraced structure according to the crystallographic orientation (OC1) of the family of planes {100} so as to form an epitaxial layer (10-2) of monocrystalline diamond.

3. Production method (100) according to one of claims 1 or 2, further comprising a step of calculating (120), from the first values ​​describing a propagation direction for each seed (10, 11, 12, 13) of monocrystalline diamond, a second value describing the angle giving the propagation direction of a main wavefront (FO) of the plurality of seeds (10, 11, 12, 13) of monocrystalline diamond, in which during the step of positioning the seeds of monocrystalline diamond of so as to form a mosaic, each seed (10, 11, 12, 13) of monocrystalline diamond comprises angles giving the directions of propagation (Dw, Du) of the wave fronts (FOw, FOn) ranging from -5° to +5° relative to the second value, preferably from -2.5° to +2.5°.

4. Production method (100) according to any one of claims 1 to 3, said method comprising a step of surfacing (115), by lithography or by laser, the crystallographic orientation faces (OC1, OC2) of the seeds (10, 11, 12, 13) of monocrystalline diamond so that said seeds have angles giving the propagation direction (D, Du) of the wave fronts (FOw, FOn) which are substantially identical.

5. Production method (100) according to claim 2 or according to any one of claims 3 or 4 taken in their dependence with claim 2, said method comprising a step of resurfacing (115') by laser or by lithography of the monocrystalline diamond plate after removal (160) of the epitaxial layer (10-2) of monocrystalline diamond, the resurfacing step (115') comprising: - a removal of a predetermined thickness of the monocrystalline diamond plate, - a formation of a new predetermined terraced structure having crystallographic orientation faces (OC1, OC2) of the seeds (10, 11, 12, 13) of monocrystalline diamond comprising families of planes {100} or crystallographic orientation faces (OC1, OC2) of the seeds (10, 11, 12, 13) of monocrystalline diamond comprising families of planes {100} and {113}.

6. Production method (100) according to claim 5, in which the seeds of the new terraced structure, formed during the resurfacing step (115') by laser or by lithography, have angles giving the direction of propagation (Dw, Du) of the wave fronts (FOw, FOn) which are substantially identical.

7. Production method (100) according to any one of claims 1 to 6, in which the lateral epitaxial growth (140) of the terraced structure according to the crystallographic orientation (OC2) of the seeds (10, 11, 12, 13) of monocrystalline diamond, comprises a step of introducing (141) a gas suitable for preventing the development of stresses or the formation of crystalline defects, preferably twins and dislocations, at the interface between the seeds.

8. A production method (100) according to any one of claims 1 to 7, wherein the terraced structure comprises macroscopic growth steps.

9. Production method (100) according to any one of claims 1 to 8, said method further comprising a step of creating (142) “XV-” centers, by doping with a suitable “X” gas, followed by irradiation by electron beam and annealing.

10. Production method (100) according to any one of claims 1 to 9, in which the single-crystal diamond seeds are positioned in order of increasing thickness according to a propagation direction defined by one of the angles (D, Du) of the wave fronts (FO, FOn).

11. A plate (1) of monocrystalline diamond obtainable by a production method (100) according to any one of claims 1 to 10, wherein at least 15%, preferably at least 50% and even more preferably at least 85%, of the junctions formed between the monocrystalline diamond seeds have a Raman peak width value at half-height greater than or equal to 2.5 cm. -1and less than 2.9 cm -1 .

12. Monocrystalline diamond obtainable by a production method (100) according to any one of claims 1 to 10, having a surface comprising at least a first crystallographic face and a second crystallographic face, said crystallographic faces each being associated with a “XV-” center concentration; the “XV-” center concentration of the first crystallographic face being greater than the “XV-” center concentration of the second crystallographic face.

13. Monocrystalline diamond according to the preceding claim, characterized in that the first crystallographic face of the monocrystalline diamond belongs to the {113} family of planes.

14. Use of a monocrystalline diamond plate according to claim 11 or of a monocrystalline diamond according to one of claims 12 or 13, for the manufacture of an optical window, of a substrate for a semiconductor or for thermal management, of a substrate for quantum technologies, or of a diamond for jewelry, preferably greater than 5 carats, preferably greater than 15 carats.

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