Abstract: There is disclosed a carbon material having a face-centered cubic crystal lattice characterized by a space group Fm-3m, and containing at least 99.9 atomic % carbon, wherein the mean grain size of the carbon material is greater than 0.5 ?m.

Abstract: A CVD single crystal diamond having a smallest linear dimension of no less than 3.5 mm, a concentration of single substitutional nitrogen atoms in their neutral charge state (Ns0), as measured by EPR, of between 20 and 250 ppb, a hue angle, hab, between 75 and 135°.

Abstract: A method of manufacturing synthetic diamond material using a chemical vapour deposition process, and a diamond obtained by such a method are described. The method comprises providing a freestanding synthetic single crystal diamond substrate wafer having a dislocation density of at least 107 cm?2. The synthetic single crystal diamond substrate wafer is located over a substrate holder within a chemical vapour deposition reactor. Process gases are fed into the reactor, the process gases including a gas comprising carbon. Crack-free synthetic diamond material is grown on a surface of the single crystal diamond substrate wafer at a temperature of at least 900° C. to a thickness of at least 0.5 mm and with lateral dimensions of at least 4 mm by 4 mm.

Abstract: A bonded diamond assembly and a method of forming the assembly. The assembly comprises a polycrystalline diamond wafer having a largest linear dimension of between 25 mm and 200 mm, a substrate and a bonding layer located between the diamond and the substrate and bonding them together. The bonding layer, when inspected using ultrasound using a resolution of 50 ?m, a focal length selected to inspect the bonding layer, and frequencies of 100 MHz and 30 MHz, comprises low numbers of voids extending either across the thickness of the bonding layer and low numbers of voids that do not extend across the thickness of the bonding layer.

Abstract: A coloured single crystal CVD synthetic diamond material comprising: a plurality of layers, wherein the plurality of layers includes at least two sets of layers which differ in terms of their defect composition and colour, wherein defect type, defect concentration, and layer thickness for each of the at least two sets of layers is such that if the coloured single crystal CVD diamond material is fabricated into a round brilliant cut diamond comprising a table and a culet, and having a table to culet depth greater than 1 mm, the round brilliant cut diamond comprises a uniform colour as viewed by naked human eye under standard ambient viewing conditions in at least a direction through the table to the culet.

Abstract: A method of manufacturing synthetic diamond material using a chemical vapour deposition process, and a diamond obtained by such a method are described. The method comprises providing a freestanding synthetic single crystal diamond substrate wafer having a dislocation density of at least 107cm?2. The synthetic single crystal diamond substrate wafer is located over a substrate holder within a chemical vapour deposition reactor. Process gases are fed into the reactor, the process gases including a gas comprising carbon. Crack-free synthetic diamond material is grown on a surface of the single crystal diamond substrate wafer at a temperature of at least 900° C. to a thickness of at least 0.5 mm and with lateral dimensions of at least 4 mm by 4 mm.

Abstract: A method of manufacturing synthetic diamond material using a chemical vapour deposition process, and a diamond obtained by such a method are described. The method comprises providing a freestanding synthetic single crystal diamond substrate wafer having a dislocation density of at least 107 cm?2. The synthetic single crystal diamond substrate wafer is located over a substrate holder within a chemical vapour deposition reactor. Process gases are fed into the reactor, the process gases including a gas comprising carbon. Crack-free synthetic diamond material is grown on a surface of the single crystal diamond substrate wafer at a temperature of at least 900° C. to a thickness of at least 0.5 mm and with lateral dimensions of at least 4 mm by 4 mm.

Abstract: A microwave plasma reactor for manufacturing synthetic diamond material via chemical vapour deposition, the microwave plasma reactor includes a plasma chamber, a substrate holder, a microwave coupling configuration for feeding microwaves into the plasma chamber, and a gas flow system for feeding process gases into the plasma chamber and removing them therefrom. The gas flow system includes a gas inlet array having a plurality of gas inlets for directing the process gases towards the substrate holder. The gas inlet array includes at least six gas inlets disposed in a substantially parallel or divergent orientation relative to a central axis of the plasma chamber.

Abstract: A method of manufacturing synthetic diamond material using a chemical vapour deposition process, and a diamond obtained by such a method are described. The method comprises providing a freestanding synthetic single crystal diamond substrate wafer having a dislocation density of at least 107 cm?2. The synthetic single crystal diamond substrate wafer is located over a substrate holder within a chemical vapour deposition reactor. Process gases are fed into the reactor, the process gases including a gas comprising carbon. Crack-free synthetic diamond material is grown on a surface of the single crystal diamond substrate wafer at a temperature of at least 900° C. to a thickness of at least 0.5 mm and with lateral dimensions of at least 4 mm by 4 mm.

Abstract: There is described a single crystal CVD diamond material comprising three orthogonal dimensions of at least 2 mm; one or more regions of low optical birefringence, indicative of low strain, such that in a sample of the single crystal CVD diamond material having a thickness in a range 0.5 mm to 1.0 mm and an area of greater than 1.3 mm×1.3 mm and measured using a pixel size of area in a range 1×1 ?m2 to 20×20 ?m2, a maximum value of ?n[average] does not exceed 1.5×10?4 for the one or more regions of low optical birefringence, where ?n[average] is an average value of a difference between refractive index for light polarised parallel to slow and fast axes averaged over the sample thickness; one or more regions of high optical birefringence, indicative of high strain, such that in said sample of the single crystal CVD diamond material and measured using said pixel size, ?n[average] is greater than 1.5×10?4 and less than 3×10?3; and is wherein every 1.3 mm×1.

Abstract: A synthetic diamond heat spreader that includes a first layer of synthetic diamond material forming a base support layer and a second layer of synthetic diamond material disposed on the first layer of synthetic diamond material and forming a diamond surface layer. The diamond surface layer has a thickness equal to or less than a thickness of the base support layer. The diamond surface layer has a nitrogen content less than that of the base support layer. The nitrogen content of the diamond surface layer and the diamond support layer is selected such that the thermal conductivity of the base support layer is in a range 1000 W/mK to 1800 W/mK and the thermal conductivity of the surface support layer is in a range 1900 W/mK to 2800 W/mK.

Abstract: A CVD single crystal diamond material suitable for use in, or as, an optical device or element. It is suitable for use in a wide range of optical applications such as, for example, optical windows, laser windows, optical reflectors, optical refractors and gratings, and etalons. The CVD diamond material is produced by a CVD method in the presence of a controlled low level of nitrogen to control the development of crystal defects and thus achieve a diamond material having key characteristics for optical applications.

Abstract: There is described a single crystal CVD diamond material comprising three orthogonal dimensions of at least 2 mm; one or more regions of low optical birefringence, indicative of low strain, such that in a sample of the single crystal CVD diamond material having a thickness in a range 0.5 mm to 1.0 mm and an area of greater than 1.3 mm×1.3 mm and measured using a pixel size of area in a range 1×1 ?m2 to 20×20 ?m2, a maximum value of ?n[average] does not exceed 1.5×10?4 for the one or more regions of low optical birefringence, where ?n[average] is an average value of a difference between refractive index for light polarised parallel to slow and fast axes averaged over the sample thickness; one or more regions of high optical birefringence, indicative of high strain, such that in said sample of the single crystal CVD diamond material and measured using said pixel size, ?n[average] is greater than 1.5×10?4 and less than 3×10?3; and is wherein every 1.3 mm×1.

Abstract: A CVD single crystal diamond material suitable for use in, or as, an optical device or element. It is suitable for use in a wide range of optical applications such as, for example, optical windows, laser windows, optical reflectors, optical refractors and gratings, and etalons. The CVD diamond material is produced by a CVD method in the presence of a controlled low level of nitrogen to control the development of crystal defects and thus achieve a diamond material having key characteristics for optical applications.

Abstract: An optical element includes a synthetic diamond material and an optical surface pattern formed directly in at least one surface of the synthetic diamond material. The optical surface pattern includes a plurality of projections separated by trenches, the projections spaced apart with a periodicity d. The periodicity d is between 65 and 99% of a zeroeth order diffraction limit above which non zeroeth diffraction orders are observed at an operating wavelength ?. The optical surface pattern has a fill fraction in a range 0.1 to 0.6, the fill fraction defined as [area of projection in one periodic unit]/[area of the periodic unit]. The optical element has an absorption coefficient measured at room temperature of ?0.2 cm-1 at a wavelength of 10.6 ?m.

Abstract: A method of fabricating a semiconductor device structure includes: providing a substrate comprising a layer of compound semiconductor material; forming a seed layer of nano-crystalline diamond having a layer thickness in a range 5 to 50 nm on the layer of compound semiconductor material; and growing a layer of polycrystalline CVD diamond on the seed layer using a chemical vapour deposition (CVD) technique. An effective thermal boundary resistance (TBReff) at an interface between the layer of compound semiconductor material and the layer of polycrystalline CVD diamond material is no more than 50 m2K/GW.

Abstract: A method of fabricating a plurality of single crystal CVD diamonds, the method comprising: coating a carrier substrate with a layer of polycrystalline CVD diamond material; bonding a plurality of single crystal diamond substrates to the layer of polycrystalline CVD diamond material on the carrier substrate; growing single crystal CVD diamond material on the plurality of single crystal diamond substrates to form a plurality of single crystal CVD diamonds; and separating the plurality of single crystal CVD diamonds from the layer of polycrystalline CVD diamond material on the carrier substrate and any polycrystalline CVD diamond material which has grown between the plurality of single crystal CVD diamonds to yield a plurality of individual single crystal CVD diamonds.

Abstract: The present disclosure relates to methods for synthesizing synthetic CVD diamond material and high quality synthetic CVD diamond materials.

Abstract: Methods of fabricating compound semiconductor device structures having polycrystalline CVD diamond. The method includes: providing a substrate that has a layer of single crystal compound semiconductor material; forming a bonding layer on a surface of the substrate, the bonding layer having a thickness of less than 25 nm and a thickness variation of no more than 15 nm; and growing a layer of polycrystalline diamond on the bonding layer using a chemical vapor deposition technique. The effective thermal boundary resistance at the interface between the layer of single crystal compound semiconductor material and the layer of polycrystalline CVD diamond material is less than 25 m2K/GW. The layer of single crystal compound semiconductor material has one or both of the following characteristics: a charge mobility of at least 1200 cm2V?1s?1; and a sheet resistance of no more than 700 ?/square.

Abstract: A semiconductor device comprising: a semiconductor component; a diamond heat spreader; and a metal bond, wherein the semiconductor component is bonded to the diamond heat spreader via the metal bond, wherein the metal bond comprises a layer of chromium bonded to the diamond heat spreader and a further metal layer disposed between the layer of chromium and the semiconductor component, and wherein the semiconductor component is configured to operate at an areal power density of at least 1 kW/cm2 and/or a linear power density of at least 1 W/mm.