Smooth surface diamond composite coating

Abstract

The diamond-coated glass structure can include a glass substrate having nanocrystalline diamond deposited thereon. An ultra-nanocrystalline diamond layer can be deposited on the deposited nanocrystalline diamond. The combination of the deposited nanocrystalline diamond and ultra-nanocrystalline diamond can have an RMS surface roughness of less than 9 nanometers.

Description

[Technical Field]

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 434,266, filed December 21, 2022, which is incorporated herein by reference in its entirety.

[0002] The present invention relates to a system and method for coating substrates or components with diamond using chemical vapor deposition (CVD). Selected apparatus and methods are disclosed to achieve high-quality composite diamond films with low surface roughness suitable for covers, displays, and optical devices. [Background technology]

[0003] Diamond films and coatings can be used to protect optical systems, coat consumer applications such as smartphone and watch displays, coat tools and machine parts, coat for chemical protection, or in electrical and semiconductor applications. Advantageously, diamond films enhance hardness, scratch resistance, water resistance, and a variety of unique electrical properties. However, commercially viable diamond films and coatings remain limited by the cost and time required to deposit useful thicknesses of diamond films on glass substrates.

[0004] What is needed is a glass / diamond structure and processing technology that will result in an optically clear, smooth, and scratch-resistant diamond coating. Summary of the Invention

[0005] Disclosed herein are new and improved systems and methods for diamond coating using a CVD system. The diamond-coated glass structure can include a glass or other suitable transparent substrate and a CVD-deposited nanocrystalline diamond coated on the substrate. A layer of ultrananocrystalline diamond can be deposited on the CVD-deposited nanocrystalline diamond. The combination of the CVD nanocrystalline diamond and the ultrananocrystalline diamond can have an RMS surface roughness of less than 9 nanometers.

[0006] In some embodiments, the CVD deposited diamond layer has a diamond layer thickness between 20 and 500 nanometers.

[0007] In some embodiments, the CVD deposited diamond layer comprises a diamond coating 70 to 500 nanometers thick with at least 50% of the diamond grains having a size between 3 nanometers and 150 nanometers.

[0008] In some embodiments, the ultra-nanocrystalline diamond layer comprises a diamond layer having a thickness of up to 500 nanometers.

[0009] In some embodiments, the ultra-nanocrystalline diamond layer comprises a diamond film less than 50 nanometers thick with at least 50% of the diamond grains being between 2 nanometers and 10 nanometers in size.

[0010] In some embodiments, the combination of the CVD deposited diamond layer, the ultrananocrystalline diamond layer deposited on the CVD deposited diamond layer, and the glass substrate transmits light with a transmittance greater than at least one of 0.80 and 0.90 at wavelengths in the range of 500 to 600 nanometers.

[0011] In some embodiments, the combination of the CVD deposited diamond layer, the ultra-nanocrystalline diamond layer deposited on the CVD deposited diamond layer, and the glass substrate provides a haze of less than 5%.

[0012] In some embodiments, the substrate has a dimension of at least 1 cm and can be at least 11 cm square.

[0013] In some embodiments, the glass substrate comprises at least one of soda glass, aluminosilicate glass, and borosilicate glass.

[0014] In some embodiments, the glass substrate is chemically modified by substituting at least a portion of the sodium ions with potassium ions.

[0015] In some embodiments, the CVD deposited diamond layer is deposited on a glass substrate at a temperature of 600 degrees Celsius or less.

[0016] In some embodiments, an oleophobic coating or other additional coating may be deposited onto the ultra-nanocrystalline diamond layer.

[0017] In some embodiments, the ultra-nanocrystalline diamond layer and the nanocrystalline diamond layer cover at least one of the top and side surfaces of the glass substrate.

[0018] In some embodiments, the ultrananocrystalline diamond layer is less than the thickness of the nanocrystalline diamond layer.

[0019] In some embodiments, the ultra-nanocrystalline diamond layer comprises a diamond coating less than 50 nanometers thick with at least 50% of the diamond grains being between 2 nanometers and 10 nanometers in size.

[0020] Other systems, methods, aspects, features, embodiments, and advantages of the systems and methods disclosed herein will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description, and it is intended that all such additional systems, methods, aspects, features, embodiments, and advantages be included within this specification and be within the scope of the appended claims. [Brief explanation of the drawings]

[0021] It should be understood that the drawings are for illustrative purposes only. Additionally, the components in the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the systems disclosed herein. In the drawings, like reference numerals indicate corresponding parts throughout the different views. [Figure 1A] FIG. 1A is an exemplary schematic diagram of a glass substrate coated on one side with a nanocrystalline (NCD) diamond layer and an ultrananocrystalline (UNCD) diamond layer. [Figure 1B] FIG. 1B is an exemplary schematic diagram of a glass substrate diamond coated with nanocrystalline (NCD) and ultrananocrystalline (UNCD) diamond layers. [Figure 2A] FIG. 2A is an exemplary block diagram of one embodiment of a method for manufacturing a glass substrate having a nanocrystalline (NCD) diamond layer and an ultrananocrystalline (UNCD) diamond layer. [Figure 2B] FIG. 2B is an exemplary block diagram of one embodiment of a method for fabricating a chemically modified glass substrate having a nanocrystalline (NCD) diamond layer and an ultrananocrystalline (UNCD) diamond layer. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following detailed description, which refers to and incorporates the drawings, describes and illustrates one or more specific embodiments. These embodiments are provided for purposes of illustration and instruction only, and are not limiting, and are shown and described in sufficient detail to enable those skilled in the art to practice what is claimed. Accordingly, for the purposes of brevity, certain information known to those skilled in the art may be omitted.

[0023] As used in this disclosure, the terms "layer," "film," and "coating" can be used interchangeably and refer to thinly deposited, chemically formed, grown, or otherwise deposited material on a substrate, which may itself be a layer, film, or coating. Diamond layers and films can include pristine diamond, diamond-like materials, or diamond containing small amounts of graphite or other materials. The diamond lattice structure can be selectively altered, including various sp2 / sp3 carbon material configurations, through selective seeding or etching, nucleation and growth process parameters such as gas composition, pressure, and temperature, selective laser annealing, particle bombardment or doping, or growth of diamond using laser pulses. Modification of diamond layers or films with oxygen termination, hydrogen termination, chlorine, or fluorine functionalization are further embodiments.

[0024] The diamond structures and methods of manufacture described herein may incorporate systems and methods previously disclosed and described in U.S. Patent Publication No. 2013 / 0026492 to Adam Khan, published January 31, 2013; U.S. Patent No. 8,354,290 to Anirudha Sumant et al., published January 15, 2013; U.S. Patent No. 8,933,462 to Adam Khan; U.S. Patent Publication No. 2015 / 0206749 to Adam Khan, published July 23, 2015; and U.S. Patent Publication No. 2015 / 0295134 to Adam Khan et al., published October 15, 2015, all of which are incorporated herein by reference in their entireties.

[0025] FIG. 1A is an exemplary schematic diagram of a glass substrate diamond-coated on one side with a nanocrystalline (NCD) diamond layer and an ultrananocrystalline (UNCD) diamond layer. As illustrated with respect to FIG. 1A, the systems and methods provided herein enable the fabrication of a partially diamond-coated glass structure 100A. The glass structure 100A includes the glass substrate 110A having a first side, a second side, and an edge. As described below, in some embodiments, the glass structure can be chemically modified using ion substitution techniques. In one embodiment, a nanocrystalline diamond layer 130A is CVD-deposited on one side (e.g., the top surface) of the glass substrate 110A. In some embodiments, the nanocrystalline layer 130A can have a thickness of 20 to 500 nanometers with grain sizes of 10 to 200 nanometers. In one embodiment, the CVD-deposited diamond layer comprises a diamond film 70 to 500 nanometers (or alternatively, 70 to 300 nm) thick with at least 50% diamond grains between 10 and 500 nanometers in size. Additionally, an ultra-nanocrystalline diamond layer 132A can be deposited on the nanocrystalline diamond layer 130A using CVD or other suitable deposition techniques. In some embodiments, the ultra-nanocrystalline diamond layer 132A can have a thickness of 20 to 500 nanometers with grain sizes of 2 to 10 nanometers. In some embodiments, the ultra-nanocrystalline diamond layer is less thick than the nanocrystalline diamond layer. In some embodiments, the ultra-nanocrystalline diamond layer comprises a diamond film less than 500 nanometers, less than 300 nanometers, or less than 200 nanometers thick with at least 50% of the diamond grains between 2 nanometers and 10 nanometers in size.

[0026] FIG. 1B is an exemplary schematic diagram of a glass substrate coated with a nanocrystalline (NCD) and ultrananocrystalline (UNCD) diamond layer. A diagram of a glass substrate having one side diamond-coated with a nanocrystalline (NCD) and ultrananocrystalline (UNCD) diamond layer. As illustrated with respect to FIG. 1B, the systems and methods provided herein enable the fabrication of a fully diamond-coated glass structure 100B. The glass structure 100B includes a glass substrate 1210B having a first side, a second side, and an edge. As described below, in some embodiments, the glass structure can be chemically modified using ion substitution techniques. In one embodiment, a nanocrystalline diamond layer 130B is CVD-deposited on all sides, edges, and corners of the glass substrate 110B. In some embodiments, the nanocrystalline layer 130B can have a thickness of 20 to 500 nanometers, typically selected between 10 and 200 nanometers, with a grain size less than the diamond film thickness. The thickness can be uniform across the entire surface, or alternatively, can vary depending on the diamond coating on the top, bottom, or edge. In one embodiment, the CVD-deposited diamond layer comprises a diamond film having at least 50% diamond grains between 10 nanometers and 500 nanometers in size, the grain size being selected to be smaller than the diamond film thickness. In some embodiments, the diamond film thickness may be less than 500 nm, less than 300 nm, less than 200 nm, or less than 150 nm. In some embodiments, the diamond film thickness is greater than 70 nm. Furthermore, CVD or other suitable deposition techniques can be used to deposit an ultrananocrystalline diamond layer 132B on the nanocrystalline diamond layer 130B. In some embodiments, the ultrananocrystalline layer 132B can have a thickness of 20 to 500 nanometers with a grain size of 2 to 10 nanometers. In some embodiments, the ultrananocrystalline layer 132B can have a thickness of less than 50 nanometers.

[0027] As will be appreciated, various types of glass substrates can be used in structures such as those described with respect to FIGS. 1A and 1B. For example, the glass can be a silicate glass, such as alkali silicate glass, soda-lime glass, alkali aluminosilicate glass, aluminosilicate glass, borosilicate glass, alkali aluminogermanate glass, alkali germanate glass, alkali gallogermanate glass, and combinations thereof. The structure can also be fabricated on infrared (IR) substrate materials, including, but not limited to, silicon (Si), zinc sulfide (ZnS), zinc selenide (ZnSe), germanium (Ge), magnesium fluoride (MGF), sapphire (Al2O3), aluminum oxynitride (AlxOyNz), spinel (MgAl2O4), calcium fluoride (CaF2), and sodium chloride (NaCl). In some embodiments, multiple types of glass or IR materials can be fused or laminated to provide the substrate. Other examples of glass types and compositions suitable for use are described in further detail in U.S. Patent 8,232,218, assigned to Corning Incorporated. As described herein, the glass substrate may be ion-exchangeable. In one embodiment, chemical modification can include subjecting the diamond-coated glass to an ion-exchange process. As used herein, the terms "ion exchange" or "ion substitution" are understood to mean that the glass can be chemically modified by an ion-exchange process known to those skilled in the art. Such ion-exchange processes include, but are not limited to, treating the glass with a solution containing ions with a larger ionic radius than the ions present on the glass surface, replacing the smaller ions with the larger ions. In one embodiment of this process, at least some ions of a first element in the surface region of the glass article are exchanged with ions of a second element, each of which has an ionic radius larger than the ionic radius of the ions of the first element being exchanged. In one embodiment, the first and second elements are alkali metals. The exchange of sodium (Na+ ions) with potassium (K+ ions) is a non-limiting example of such an ion exchange.Alternatively, other alkali metal ions with larger atomic radii, such as rubidium or cesium, can replace the smaller alkali metal ions in the glass. In another embodiment, the small alkali metal ions are replaced with silver (Ag+) ions. In some embodiments, additional elements such as Li+, Rb+, Cs+, Cd2+, Zn2+, or Cu+ / Cu2+ can be used. As will be appreciated, ion exchange can occur before or after diamond coating, and multiple ion exchanges can occur during glass processing.

[0028] Ion exchange can be carried out using methods known in the art and described herein. Depending on the ion penetration depth and other properties, chemical modification of a glass substrate by ion exchange can result in strengthening, hardening, or both of the glass. In one embodiment, the ion exchange is carried out by immersing the glass in a molten salt bath composed of an alkali metal salt, such as potassium nitrate (KNO), for a predetermined period of time. In some embodiments, the glass substrate can be chemically modified in a single ion exchange process. In some embodiments, the glass substrate is immersed in a molten salt bath containing a salt of a large alkali metal cation. In some embodiments, the molten salt bath comprises, or consists essentially of, a salt of a large alkali metal cation. In some embodiments, the single ion exchange process is carried out at a temperature below 600°C, while in other embodiments, the temperature is between 275°C and 550°C for a time sufficient to achieve the desired ion depth penetration (which in some embodiments increases as the glass thickness increases, and in some embodiments is between 5 and 300 microns).

[0029] In another embodiment, a glass substrate can be chemically modified using a two-step or dual ion exchange process. In the first step of this process, the glass substrate is ion-exchanged in a first molten salt bath. After the first ion exchange is completed, the glass is optionally diamond-coated and then immersed in an additional ion exchange bath (e.g., a second ion exchange bath). The additional or second ion exchange bath can have the same composition as the first ion exchange bath. Alternatively, the additional or second ion exchange bath can have a different composition from the first ion exchange bath and / or can be operated at a different immersion time and temperature.

[0030] In some embodiments, the ion-exchanged glass substrate bearing the nanocrystalline and ultrananocrystalline composite diamond coating can be used as a cover glass for housing consumer electronic displays. For example, either the untreated glass substrate bearing the diamond coating or the ion-exchanged glass substrate is particularly suitable for glass covers or displays (e.g., LCD displays) assembled into small form factor electronic devices such as handheld electronic devices (e.g., mobile phones, media players, personal digital assistants, remote controls, etc.). The present apparatus, systems, and methods can also be used for glass covers or displays for other relatively large form factor electronic devices (e.g., portable computers, tablet computers, displays, monitors, televisions, etc.). In these embodiments, the glass substrate bearing the diamond coating can form part of the display area of ​​the electronic device (e.g., as a separate component or integrated within the display and located in front of the display). Alternatively or additionally, the glass member can form part of the housing, for example, forming an exterior surface other than the display area.

[0031] The thickness of the glass or other transparent substrate can be less than 5 mm, and in some embodiments, between 0.5 and 3 mm. In particularly thin embodiments, the glass substrate may be 0.3 mm to 1 mm thick. In some embodiments, the glass substrate may be 0.25 to 3 mm thick. In other embodiments, the thickness may be less than 2 mm, less than 1 mm, or less than 0.6 mm.

[0032] In one embodiment, the edges of the glass substrate can be formed and chemically modified to correspond to a specific, predetermined shape, thereby increasing the compression near the edges of the glass cover. This can make the glass cover stronger by imposing a specific, predetermined shape on the edges of the glass cover. In one embodiment, the surface of the glass cover, e.g., the edges, can be chemically modified. In one embodiment, the shape of the edges is configured to reduce or smooth sharp transitions, such as corners.

[0033] In some embodiments, one or more edges of the glass substrate can be curved or chamfered. A chamfer refers to a chamfered edge that substantially connects two sides or surfaces (e.g., top and bottom surfaces). As an example, the edge shape can include a 0.2 to 0.5 millimeter chamfered edge that extends at least partially between the top and bottom surfaces of the glass substrate. Advantageously, the use of the chamfered edge can reduce compressive stress. Alternatively or additionally, in one embodiment, the edges of the glass substrate can include smoothed corners, e.g., the corners between a first surface and a second surface (e.g., a side surface substantially perpendicular to the top / bottom surface) can be blunt. As another example, the transition between the top surface and the side surface or the transition between the bottom surface and the side surface can be smooth. In some embodiments, the edges of the glass can be rounded according to a predetermined edge shape having a predetermined edge radius (or predetermined curvature) of at least 10% of the thickness applied to the corners of the edge of the glass. In other embodiments, the predetermined edge radius can be 20% to 50% of the glass thickness. In one embodiment, the glass cover can extend to the edge of the housing of the electronic device without a protective bezel or other barrier. In one embodiment, the glass cover can include a bezel surrounding each edge. The glass cover can be disposed over or integrated with a display, such as a liquid crystal display (LCD) display available for smartphones, watches, or tablets.

[0034] In some embodiments, the glass substrate structure can undergo optional processing steps. Such processing steps can include applying one or more additional coatings or laminations (e.g., organic, polymer, inorganic, or graphene) to the glass substrate. In some embodiments, the entire substrate can be provided with an additional coating, while in other embodiments, at least one of the top, bottom, edge, or corner of the glass substrate can be provided with a coating.

[0035] In some embodiments, prior to depositing the diamond or diamond-like coating or film, the substrate can be treated by sputtering, evaporation, atomic layer deposition (ALD), chemical vapor deposition, plasma, thermal deposition, or other methods, including, but not limited to, oxide and nitride dielectric materials. These materials include oxides of metals such as titanium, indium, tin, zinc, or combinations thereof; graphene oxides such as reduced fluorinated graphene oxide; oxides of silicon, titanium, or aluminum; oxynitrides; and nitrides of metals such as aluminum, silicon, titanium, boron, and tungsten and titanium. These intermediate materials can enable or improve: 1) adhesion of subsequent layers; 2) system optical properties such as transmittance and reflectance; 3) system stress via enhanced thermal coefficients of transition; 4) reduced surface roughness; and other properties. In some embodiments, for metals deposited via sputter deposition, power levels can be adjusted and shutter open times can be varied to achieve a uniform target thickness across the display glass surface. For oxides and nitrides, thin films can utilize lower temperatures, including temperatures below 600°C. In some embodiments, this can advantageously reduce differences in thermal expansion coefficients, reduce interlayer and subsurface stresses, and allow for tailoring of color and visual uniformity, as well as optical losses due to haze or reflectivity.

[0036] Substrates can be seeded with diamond crystal particles to promote the growth of diamond layers or films of selected grain sizes. Seed layers can be formed using selective deposition or etched seed regions. In some embodiments, nanocrystalline diamond can be deposited directly or in solution. In some embodiments, seed sizes range from 5 to 50 nanometers. The seeds can be functionalized or have a positive, negative, or neutral zeta potential. The seed crystals can be in a solvent, dimethyl sulfoxide, oil, photoresist, deionized water, combinations thereof, or similar types of suspensions or matrices. Diamond crystal seeds can be uniformly distributed at 105 to 1013 grains per square centimeter, non-uniformly distributed, or locally distributed in selected areas using masks, selective spraying, electrospraying, ultrasonic spraying, sonication, or other forms of spatially localized application. In some embodiments, seeds of different sizes and properties can be used.

[0037] In some embodiments, the diamond layer formed on the diamond seed substrate may have an sp2 concentration of less than 20% by volume of the diamond layer. <111> or <100> It may have at least 80% grain orientation in any one of the crystal directions. In yet another embodiment, the highly oriented diamond film may include different crystal orientations in selected regions or layers, <111> and <100> Each crystal direction is dominant.

[0038] Diamond properties can be measured and characterized using Raman spectroscopy. Cubic diamond has a single Raman-active first-order phonon mode at the center of the Brillouin zone. The presence of sharp Raman lines allows cubic diamond to be distinguished from the background of graphite or other carbon crystals. Slight shifts in band wavenumber indicate the composition and properties of the diamond. In some embodiments, the full width at half maximum (FWHM) obtained from Raman characterization at 1332 cm-1 of the diamond layer or film formed as described herein may be between 5-20 cm-1 for SiN or other suitable buffer layer coated glasses, and between 20-85 cm-1 for RIE (reactive ion etched) or other surface treated glasses. In other embodiments, the deposited diamond layer is measured by Raman analysis to have a relative amplitude at 1332 cm-1 of 0.5:1 or greater compared to the amplitude at 1400-1600 cm-1. In other embodiments, the diamond layer may have a physical property such as a Vickers hardness as measured by nanoindentation of at least 12 gigapascals. In other embodiments, the Vickers hardness may be greater than 20 gigapascals. In other embodiments, the diamond layer is measured to exert a compressive stress of less than 50 gigapascals.

[0039] In some embodiments, a polycrystalline diamond or diamond-like carbon (DLC) coating or material can be formed on all or at least a portion of the substrate. In some embodiments, polycrystalline diamond particles less than 1 micron (1000 nanometers) and greater than 500 nanometers in size can be used. In other embodiments, the polycrystalline diamond or diamond-like material can include an ultracrystalline (UNCD) grain size (2-10 nanometers), a nanocrystalline grain size (10-500 nanometers), or a microcrystalline grain size (500 nanometers or greater). In some embodiments, the diamond grain size may encompass a range of grain sizes, including larger and smaller grain sizes. In some embodiments, the diamond layer may be formed with grains less than 1 micron in size. In some embodiments, the grain size may vary by more than or less than 50%, 100%, 200%, or 500% of the average diamond grain size. In other embodiments, the diamond grain size can be maintained within 50%, 20%, or 10% of the average grain size. In some embodiments, 50%, 60%, 80%, or 90% of the diamond particles may be between 50 nanometers and 500 nanometers in size. In some embodiments, the diamond layer may be formed from at least 90% nanocrystalline diamond and have diamond particles between 2 nanometers and 500 nanometers in size. In some embodiments, the diamond layer may be formed from at least 90% microcrystalline diamond and have diamond particles between 500 nanometers and 1000 nanometers in size. In other embodiments, the diamond grains may be between 500 nanometers and 1000 nanometers in size. In other embodiments, 90% of the diamond particles may be between 200 nanometers and 300 nanometers in size.

[0040] In some embodiments, the thickness of the diamond layer can be selected to be between 20 nanometers and 1000 nanometers. Typically, the diamond grain size is less than the diamond layer thickness, and in some embodiments, may be less than 50% of the diamond layer thickness. In some embodiments useful for optical coatings, the diamond layer thickness is between 20 nanometers and 500 nanometers. For example, in one embodiment, glass or other transparent materials can be coated with a diamond film having a thickness of 70 to 300 nanometers.

[0041] The diamond layer can have a substantially uniform thickness across all or a defined portion of the surface or substrate. In other embodiments, the thickness can be non-uniform and vary across portions of the surface or substrate. In some embodiments, the diamond layer can be conformal when extending over cavities, depressions, or protrusions in the substrate or surface. In some embodiments, the diamond layer can steadily thin or thicken away from one or more locations on the substrate.

[0042] Multiple diamond layers differentiated by composition, crystal structure, dopant, grain size, grain size distribution can be part of a multi-layer coating or film system applied to a substrate. The differentiated diamond layers can be layered on top of a diamond layer or a non-diamond material. In certain embodiments, the physical parameters of the diamond layers can vary continuously or semi-continuously vertically or laterally through the layer.

[0043] In certain embodiments, the diamond layer has a thickness, for example, between 30 and 150 nanometers (e.g., 30 nanometers, 40 nanometers, 50 nanometers, 60 nanometers, 70 nanometers, 80 nanometers, 90 nanometers, 100 nanometers, 110 nanometers, 120 nanometers, 130 nanometers, 140 nanometers, or 150 nanometers, including all ranges and values ​​therebetween). Furthermore, the diamond layer can have a root mean square (RMS) surface roughness of less than 2 nanometers. In certain embodiments, the diamond layer has a root mean square (RMS) surface roughness of less than 11, 10, 9, 8, or 7, 6, 5, 4, 3, or 2 nanometers. In some embodiments, the diamond layer has an RMS roughness of less than 50%, 40%, 30%, 20%, or 10% of the film thickness. In some embodiments, the diamond layer has an RMS roughness of less than 20% of the diamond layer thickness.

[0044] Diamond or DLC can be deposited by chemical vapor deposition (CVD) techniques such as hot-filament chemical vapor deposition (CVD), microwave CVD, RF-CVD, laser-assisted CVD (LCVD), or laser ablation, metalorganic CVD (MOCVD), sputtering, thermal evaporation PVD, ionized metal PVD (IMPVD), electron beam PVD (EBPVD), reactive PVD, and cathodic arc. CVD uses a dilute mixture of hydrogen and a carbon-containing gas, such as carbon dioxide or a hydrocarbon, typically methane, with the carbon-containing component typically comprising approximately 0.1%–4% of the total volumetric flow. In one of these techniques, the gas mixture is energized through a metal filament (usually tungsten), which is electrically heated to temperatures ranging from approximately 170°C to 2400°C. The gas mixture dissociates at the filament surface, and the hybridized carbon in the form of diamond is deposited on a substrate placed below the filament. During operation, the power density at the substrate is 300–600 W / m² / min. Deposition is typically carried out at subatmospheric pressures in the range of 30 mTorr to 300 Torr.

[0045] In some embodiments, diamond films can be deposited on substrates having substrate temperatures below 600°C. In other embodiments, deposition can occur at temperatures between 300 and 600°C. Advantageously, compared to the typical temperatures of 700-800°C for conventional CVD diamond film growth, these lower temperatures significantly reduce thermal effects such as thermal degradation, CTE differential stress, and substrate warpage. Advantageously, this allows for the use of a wider variety of substrates and coatings.

[0046] In some embodiments, various processes can be used to improve the quality of diamond or other films. These treatments can be performed, for example, before seeding, before layer deposition, after layer deposition, or after a metrology step that contaminates the surface. For example, the substrate can be subjected to dry and / or wet treatments, including, but not limited to, strong and / or weak acid and / or base cleaning, solvent cleaning, ultrasonic agitation, plasma cleaning, ultraviolet (UV) light, ozone treatment, tetramethylammonium hydroxide application, or any other suitable process combination. Plasma cleaning can include exposing the substrate to various concentrations of argon and / or oxygen-derived plasma. Post-diamond deposition cleaning steps can include solvent cleaning with solvents such as acetone or IPA, or plasma cleaning with O2 / Ar gas using RIE or similar, to clean the substrate to remove unwanted residues deposited during the diamond deposition process.

[0047] In some embodiments, a glass or other substrate can support multiple thin diamond layers, various intermediate layers, layers pretreated using reactive ion etching (RIE) or other techniques, and a top layer. These can be thin single or multiple layers of metal, ceramic, glass, or other compositions. The thickness of such layers can be less than 1000 nanometers. Such layers can function as capping, intermediate, or buffer layers and can improve the optical, electrical, thermal, or mechanical properties of the multilayer structure. In some embodiments, the capping, intermediate, or buffer layer can be transparent and comprise one or more of a metal (e.g., tungsten or titanium), a ceramic, a dielectric material, or a glass (e.g., an aluminosilicate or borosilicate). In some embodiments, the capping, intermediate, or buffer layer can comprise one or more of indium tin oxide, aluminum oxide, oxynitride, titanium oxide, magnesium oxide, silicon dioxide, and hafnium oxide, including but not limited to titanium dioxide. In other embodiments, the cap layer, intermediate layer, or buffer layer may include one or more of aluminum, silicon, titanium, or boron nitride. The cap layer, intermediate layer, or buffer layer may also include, but is not limited to, a carbon film formed of diamond-like carbon (DLC), amorphous carbon, or nanocrystalline diamond (NCD), a metal film formed of molybdenum, titanium, tungsten, chromium, or copper, or a ceramic film formed of SiC, TiC, CrC, WC, BN, B4C, Si3N4, TiN, CrN, SiCN, or BCN. The thickness of the cap layer, intermediate layer, or buffer layer may range from 2 nanometers to 1000 nanometers.

[0048] In some embodiments, the deposited diamond film can be washed and exposed to a two-dimensional top layer material such as reduced fluorinated graphene oxide, graphene, graphene oxide, or f-silane. In some embodiments, this can result in superhydrophobic or oleophobic properties without significantly degrading the diamond film's properties, including optical transmittance and / or hardness. In one embodiment, the graphene oxide is derived from a chemical suspension of multilayer graphene oxide, spun onto the diamond film, and then wet-chemically or dry-chemically (plasma-) reduced by incorporating fluorine atoms into the material, substituting for oxygen.

[0049] In some embodiments, the substrate and / or diamond layer may be subjected to a surface functionalization treatment step, which may include spray coating, bias spray coating, ultrasonic spray coating, or wet chemistry surface functionalization using ultrasonic agitation of solvents and ketone mixtures, including, but not limited to, methanol, acetone, isopropyl alcohol, ethanol, butanol, or pentanol. The functionalized surface may include hydrocarbon chains, hydroxyl bonds, oxygen terminations, or other suitable chemically active materials.

[0050] FIG. 2A is an exemplary block diagram of one embodiment of a method for fabricating a chemically modified glass substrate structure having a nanocrystalline (NCD) and ultrananocrystalline (UNCD) diamond layer, as illustrated with respect to FIG. 1A. In this embodiment, in a first step 210A, a glass substrate is prepared by cleaning and seeding with nanocrystalline diamond. In a second step 212A, CVD diamond is formed on at least a first side. The first side can be a top, bottom, edge, or corner. In addition to the first side, second, third, etc. sides can also be coated with CVD diamond. In step 214B, CVD ultrahigh-crystallinity diamond is formed on at least the first side and, optionally, other side or edge portions.

[0051] FIG. 2B is an exemplary block diagram of one embodiment of a method for fabricating a chemically modified glass substrate structure having a nanocrystalline (NCD) diamond layer and an ultrananocrystalline (UNCD) diamond layer as illustrated with respect to FIG. 1B. In this embodiment, in a first step 210B, at least a first and a second side of the glass substrate structure are chemically modified using ion substitution. The second side can be one of a top surface, a bottom surface, an edge, or a corner. In step 212B, CVD nanocrystalline diamond is formed on at least the first side. The first side can be one of a top surface, a bottom surface, an edge, or a corner. In addition to the first side, in some embodiments, additional second, third, etc. sides can be coated with CVD diamond. In step 214B, CVD ultrananocrystalline diamond is formed on at least the first side. The first side can be one of a top surface, a bottom surface, an edge, or a corner. In addition to the first side, in some embodiments, additional second, third, etc. sides can be coated with CVD ultra-non-crystalline diamond. In some embodiments, an optional treatment step can include applying a laminate (e.g., an organic, polymer, inorganic, or graphene coating) to at least one of the top, bottom, edge, or corner chemically modified glass substrate structures.

[0052] In some embodiments, the substrate can be exposed to a gas. In other embodiments, a cooled substrate wafer stage can be used to maintain temperatures below 500°C, allowing for multilayer integration without exceeding stress, softening, or strain limits in the underlying material layers. Energy for the diamond growth process is typically derived substantially from a thermally activated filament source or a microwave activated plasma source. The deposition of the diamond layer and diamond structure, or further surface treatment, surface polishing, and packaging are provided.

[0053] In some embodiments, single or multiple diamond layers or films can comprise multilayer structures that enable or enhance various applications or functions, including anti-reflection (AR) layers, light redirection, light interference, cover glass functionality, protective covers, hydrophobic or oleophobic coatings, displays or window applications, or those providing chemical, thermal, or mechanical protection. Applications or components that support multilayer diamond layers, films, or coatings include, but are not limited to, visible or infrared optics, windows, optical waveguides, semiconductors, semiconductor coatings, and tough or durable coatings for electronics, manufacturing, or tooling. Other applications of diamond multilayers include use in biological substrates and medical devices, batteries, fuel cells, electrochemical systems, chemical sensors, general sensing, and integration with other advanced materials.

[0054] When used in an optically transmissive system, the diamond film has a transmittance of greater than 0.60, 0.70, 0.80, or 0.90 for light at a wavelength of 550 nanometers through the glass substrate and diamond film, less than 0.60, 0.70, 0.80, or 0.90 for light between 350 and 450 nanometers, and less than 0.60, 0.70, 0.80, or 0.90 for light between 750 and 850 nanometers. In other embodiments of the optically transmissive system, the diamond film provides a transmittance of greater than 0.60, 0.70, 0.80, or 0.90 for light at wavelengths between 500 and 600 nanometers, between 530 and 570 nanometers, or between 540 and 560 nanometers through the glass substrate and diamond film. In some embodiments, glass or other transparent materials can be coated with diamond films that provide haze less than 20% for thick diamond layers (e.g., in the range of 1 micron to 10 microns), less than 10% for thin diamond layers (e.g., in the range of 200 nanometers to 1000 nanometers), and less than 5% for very thin diamond layers (e.g., 200 nanometers or less). In other embodiments, thick diamond layer coatings up to 10 microns can be used to improve mechanical, frictional, and thermal properties.

[0055] The diamond layer can have a substantially uniform thickness across all or a defined portion of the surface or substrate. In other embodiments, the thickness can vary across portions of the surface or substrate. In some embodiments, the diamond layer can be conformal when extending over cavities, depressions, or protrusions in the substrate or surface. In some embodiments, the diamond layer steadily thins or thickens from one or more locations on the substrate. In some embodiments, the thinning or thickening can be less than 20%, 10%, 6%, or 3% of the thickness of the diamond layer on the substrate.

[0056] As will be appreciated, the described diamond layers, substrates, and thin films of non-diamond material can include a variety of embodiments, properties, and combinations, including but not limited to the following additional examples.

[0057] Example 1—In a first example, a multilayer transparent diamond structure including a nanocrystalline diamond layer and an ultrananocrystalline diamond layer can be continuously and conformally coated onto a transparent glass substrate to serve as an optically transparent protective coating suitable for smartphones, tablets, or laptops. For example, a substantially uniformly thick nanocrystalline diamond film having a grain size ranging from 20 to 70 nanometers and a thickness of 20 to 110 nanometers can be deposited onto a conductive indium tin oxide (ITO) film deposited on the transparent glass substrate. In some embodiments, an ultrananocrystalline diamond layer having a thickness of 20 to 500 nanometers and a grain size between 2 and 10 nanometers can be deposited onto the nanocrystalline diamond layer. In some embodiments, the ultrananocrystalline diamond layer can have a thickness of 20 to 200 nanometers with a diamond grain size between 2 and 10 nanometers. In some embodiments, the ultrananocrystalline diamond layer can have a thickness of less than 50 nanometers, with at least 50% of the ultrananocrystalline diamond grains being between 2 and 10 nanometers in size. Optionally, a hydrophobic coating, or an additional diamond coating doped or functionalized to support a hydrophobic or oleophobic coating, can be deposited on the ultrafine crystalline diamond layer. The glass substrate can be chemically cleaned with acetone followed by UV ozone cleaning. Alternatively, substrates such as float glass can be acid-cleaned to remove metal coatings such as tin. In some embodiments, the glass surface can be functionalized to include hydrocarbon chains derived from solvent decomposition during drying.

[0058] Conventional HF CVD reactors using tungsten, tantalum, or rhenium filaments can be used. The diameter, spacing, and number of filaments can be adjusted to achieve optimal results. In one embodiment, the filament diameter is 0.12 to 0.5 mm, the spacing is 8 to 30 mm, and 7 to 28 filaments are used. The chamber can be of any suitable shape, such as spherical, rectangular, or cylindrical. In one embodiment, the cylindrical sphere can be sized to have a volume between 100 and 200 liters and a diameter between 30 and 150 centimeters.

[0059] The reactor can include stages capable of supporting heating or cooling of the substrate. In some embodiments, the reactor stages can be configured to provide substrate deposition temperatures between 500 and 600 degrees Celsius. At these temperature ranges, the diamond layer deposition rate can be between 10 and 100 nanometers per hour, and in other embodiments, less than 10 nanometers per hour.

[0060] Precursor gases containing methane, hydrogen, oxygen, and argon can be introduced into the chamber at pressures of 5 to 50 Torr. In particular, the addition of less than 1% oxygen can reduce the temperature required to maintain the expected deposition rate, and oxygen preferentially etches sp2 deposition regions. The methane concentration can be 0.05 to 5% of the total gas volume. The hydrogen concentration can be 60 to 98 percent of the total gas volume. The argon concentration can be 0 to 40 percent of the total gas volume.

[0061] To ensure a consistent particle size, the substrate can be coated with diamond seeds dispersed in dimethyl sulfoxide (DMSO) or other solvent solutions, including but not limited to ethanol, methanol, IPA, acetone, and pure water. In some embodiments, particle sizes between 5 and 50 nanometers can be used.

[0062] In some embodiments, the diamond film is continuous and conformal on the substrate.

[0063] Furthermore, the diamond film has a FWHM of 5-7 and an sp2 concentration of less than 20% by volume. <111> The diamond film has at least 80% grain orientation in the crystallographic direction, a diamond signature by Raman spectroscopy (wavelength approximately 1332 nm) that is 0.7:1 to 1.21:1 compared to the peak graphite band by Raman analysis (wavelength 1400-1600 nm), a Vickers hardness of 20-60 gigapascals, and a glass substrate-to-diamond film optical transmittance of greater than 0.70 at a wavelength of 550 nanometers, with a haze of less than 5%.

[0064] Example 2—In a second example, a substrate can be coated with a substantially uniform 100-2000 nanometer thick nanocrystalline diamond layer or film having a grain size in the 100-2000 nanometer range, and a thinner ultrananocrystalline diamond layer. In some embodiments, the ultrananocrystalline diamond layer can have a thickness of 20-200 nanometers with a grain size of 2-10 nanometers. In some embodiments, the ultrananocrystalline diamond layer can have a thickness of less than 50 nanometers, with at least 50% of the ultrananocrystalline diamond grains having a size between 2 nanometers and 10 nanometers. In one embodiment, the 100-2000 nanometer thick nanocrystalline diamond film and the coated ultrananocrystalline diamond layer can be further etched, and additional layers or films can be selectively applied to fill the etched diamond and support the formation of waveguides for data transmission. In some embodiments, the deposited grain size can include diamond grains in the 5-50 nanometer range.

[0065] The reactor can include stages capable of supporting heating or cooling of the substrate. In some embodiments, the reactor stages can be configured to provide substrate deposition temperatures between 500 and 800 degrees Celsius. In these temperature ranges, the diamond layer deposition rate can be between 10 and 200 nanometers per hour.

[0066] Substrates can be coated with diamond seeds dispersed in DMSO or other solvent solutions, including, but not limited to, ethanol, methanol, IPA, acetone, and pure water. In some embodiments, particle sizes between 5 and 150 nanometers can be used, with larger particles typically being reduced in size by sonication or other processing steps. In some embodiments, various particle sizes or particle size ranges can be used, including co-deposition of small and large particles. In some embodiments, the seeds are deposited in a manner that ensures a continuous and conformal film on the substrate.

[0067] In some embodiments, the diamond layer or film may have a Young's modulus greater than 80 gigapascals.

[0068] Example 3 - In a third example, a substrate can be coated with multiple layers, including diamond, ceramic, or metal layers. In some embodiments, a substantially uniform nanocrystalline diamond layer or film can be deposited that is 5-50 nanometers thick and has a grain size in the range of 5-50 nanometers. In some embodiments, an ultrananocrystalline diamond layer can be deposited that may have a thickness of 20-200 nanometers and a grain size of 2-10 nanometers. In some embodiments, the ultrananocrystalline diamond layer can have a thickness of less than 50 nanometers, with at least 50% of the ultrananocrystalline diamond grains having a size between 2 nanometers and 10 nanometers.

[0069] The reactor may include stages capable of supporting heating or cooling of the substrate. In some embodiments, the reactor stages may be configured to provide substrate deposition temperatures between 500 and 600 degrees Celsius. In these temperature ranges, the diamond layer deposition rate may be between 10 and 100 nanometers per hour.

[0070] In the foregoing description, reference has been made to the accompanying drawings that form a part hereof, and in which are shown, by way of illustration, specific exemplary embodiments in which the present disclosure may be practiced. These embodiments have been described in sufficient detail to enable those skilled in the art to practice the concepts disclosed herein, it being understood that changes can be made in the various disclosed embodiments and other embodiments can be utilized without departing from the scope of the present disclosure. Accordingly, the foregoing detailed description is not to be taken in a limiting sense.

[0071] References throughout this specification to "one embodiment," "an embodiment," "one example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases "in one embodiment," "in an embodiment," "one example," or "an example" in various places throughout this specification do not necessarily all refer to the same embodiment or example. Furthermore, particular features, structures, databases, or characteristics may be combined in any suitable combinations and / or subcombinations in one or more embodiments or examples. Additionally, it should be understood that the figures provided herein are for illustrative purposes for persons skilled in the art, and that the drawings are not necessarily drawn to scale.

[0072] Many modifications and other embodiments of the invention will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. It is understood, therefore, that the invention is not limited to the particular embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims. It is also understood that other embodiments of the invention may be practiced in the absence of elements / steps not specifically disclosed herein.

Claims

1. 1. A diamond-coated glass structure comprising: A transparent substrate; nanocrystalline diamond deposited on the transparent substrate; an ultra-nanocrystalline diamond layer deposited on the nanocrystalline diamond; and the combination of deposited nanocrystalline diamond and ultrananocrystalline diamond has an RMS surface roughness of less than 9 nanometers; structure.

2. 10. The structure of claim 1, wherein the deposited nanocrystalline diamond and ultrananocrystalline diamond layers have a combined thickness of 20 to 500 nanometers.

3. 10. The structure of claim 1, wherein the deposited nanocrystalline diamond and ultrananocrystalline diamond layers together comprise a film 70 to 500 nanometers thick with at least 50% of diamond grains having a size between 3 nanometers and 150 nanometers.

4. 10. The structure of claim 1, wherein the ultra-nanocrystalline diamond layer comprises a diamond layer having a thickness of less than 500 nanometers.

5. 10. The structure of claim 1, wherein the ultra-nanocrystalline diamond layer comprises a diamond film less than 500 nanometers thick with at least 50% of the diamond grains having a size between 2 nanometers and 10 nanometers.

6. 10. The structure of claim 1, wherein the transparent substrate is sized to have an area of ​​at least 1 square centimeter.

7. 10. The structure of claim 1, wherein the transparent substrate is glass comprising at least one of soda glass, aluminosilicate glass, borosilicate glass, alkali silicate glass, soda-lime glass, alkali aluminosilicate glass, alkali aluminogermanate glass, alkali germanate glass, and alkali gallogermanate glass.

8. 10. The structure of claim 1, wherein the transparent substrate is chemically modified by ion substitution.

9. 10. The structure of claim 1, wherein the transparent substrate is chemically modified by substituting at least a portion of the sodium ions with potassium ions.

10. 10. The structure of claim 1, wherein the transparent substrate is chemically modified by ion substitution of at least a portion of the ions to a penetration depth of less than 100 microns.

11. 10. The structure of claim 1, wherein at least one additional coating is deposited on the ultra-nanocrystalline diamond layer.

12. 2. The structure of claim 1, wherein the ultrananocrystalline diamond layer and the nanocrystalline diamond layer cover at least one of the top and side surfaces of the transparent substrate.

13. 10. The structure of claim 1, wherein the ultra-amorphous diamond layer has a thickness that is less than the thickness of the nanocrystalline diamond layer.

14. 10. The structure of claim 1, wherein the ultra-nanocrystalline diamond layer comprises a diamond film less than 500 nanometers thick with at least 50% of the diamond grains having a size between 2 nanometers and 10 nanometers.

15. 1. A method of forming a diamond coated glass structure, comprising: providing a transparent substrate; depositing nanocrystalline diamond on the transparent substrate; depositing an ultra-nanocrystalline diamond layer on the nanocrystalline diamond; and The combination of deposited nanocrystalline diamond and ultrananocrystalline diamond has an RMS surface roughness of less than 9 nanometers. method.

16. 16. The method of claim 15, wherein the nanocrystalline diamond layer comprises a diamond layer having a thickness of less than 500 nanometers.

17. 16. The method of claim 15, wherein the deposited nanocrystalline diamond and ultrananocrystalline diamond layers together comprise a film 70 to 500 nanometers thick with at least 50% of diamond grains having a size between 3 nanometers and 150 nanometers.

18. 16. The method of claim 15, wherein the ultra-nanocrystalline diamond layer comprises a diamond layer having a thickness of less than 500 nanometers.

19. 16. The method of claim 15, wherein the transparent substrate is glass comprising at least one of soda glass, aluminosilicate glass, borosilicate glass, alkali silicate glass, soda-lime glass, alkali aluminosilicate glass, alkali aluminogermanate glass, alkali germanate glass, and alkali gallogermanate glass.

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