Abstract: Disclosed herein are methods of manufacturing synthetic CVD diamond material including orienting and controlling process gas flow in a microwave plasma reactor to improve performance. The microwave plasma reactor includes a gas flow system with a gas inlet comprising one or more gas inlet nozzles disposed opposite the growth surface area and configured to inject process gases towards the growth surface area. The method comprises injecting process gases towards the growth surface area at a total gas flow rate equal to or greater than 500 standard cm3 per minute wherein the process gases are injected into the plasma chamber through the one or more gas inlet nozzles with a Reynolds number in a range 1 to 100.

Abstract: A method of cutting a super-hard material (8) using an electron beam (6), wherein the electron beam (6) is directed onto a surface of the super-hard material (8) and moved relative to the surface such that the electron beam (6) moves across the surface of the super-hard material (8) at an electron beam scanning velocity in a range 100 to 5000 mms?1 to cut the super-hard material (8).

Abstract: A microwave plasma reactor for manufacturing synthetic diamond material via chemical vapour deposition, the microwave plasma reactor comprising: a plasma chamber; a substrate holder disposed in the plasma chamber and comprising a supporting surface for supporting a substrate on which the synthetic diamond material is to be deposited in use; a microwave coupling configuration for feeding microwaves from a microwave generator into the plasma chamber; and a gas flow system for feeding process gases into the plasma chamber and removing them therefrom; wherein the microwave plasma reactor further comprises an electrically conductive plasma stabilizing annulus disposed around the substrate holder within the plasma chamber.

Abstract: A free-standing non-planar polycrystalline CVD synthetic diamond component which comprises a nucleation face and a growth face, the nucleation face comprising smaller grains than the growth face, the nucleation face having a surface roughness Ra no more than 50 nm, wherein the free-standing non-planar polycrystalline CVD synthetic diamond component has a longest linear dimension when projected onto a plane of no less than 5 mm and is substantially crack free over at least a central region thereof, wherein the central region is at least 70% of a total area of the free-standing non-planar polycrystalline CVD synthetic diamond component, wherein the central region has no cracks which intersect both external major faces of the free-standing non-planar polycrystalline CVD synthetic diamond component and extend greater than 2 mm in length.

Abstract: A microwave power delivery system for supplying microwave power to a plurality of microwave plasma reactors (8), the microwave power delivery system comprising: a tuner (14) configured to be coupled to a microwave source (4) and configured to match impedance of the plurality of microwave plasma reactors to that of the microwave source; and a waveguide junction (18) coupled to the tuner and configured to guide microwaves to and from the plurality of microwave plasma reactors, wherein the waveguide junction comprises four waveguide ports including a first port coupled to the tuner, second and third ports configured to be coupled to respective microwave plasma reactors, and a fourth port coupled to a microwave sink (20), wherein the waveguide junction is configured to evenly split microwave power input from the tuner through the first port between the second and third ports for providing microwave power to respective microwave plasma reactors, wherein the waveguide junction is configured to decouple the second a

Abstract: A method of cutting a super-hard material (8) using an electron beam (6), wherein the electron beam (6) is directed onto a surface of the super-hard material (8) and moved relative to the surface such that the electron beam (6) moves across the surface of the super-hard material (8) at an electron beam scanning velocity in a range 100 to 5000 mms?1 to cut the super-hard material (8).

Abstract: A free-standing non-planar polycrystalline CVD synthetic diamond component which comprises a nucleation face and a growth face, the nucleation face comprising smaller grains than the growth face, the nucleation face having a surface roughness Ra no more than 50 nm, wherein the free-standing non-planar polycrystalline CVD synthetic diamond component has a longest linear dimension when projected onto a plane of no less than 5 mm and is substantially crack free over at least a central region thereof, wherein the central region is at least 70% of a total area of the free-standing non-planar polycrystalline CVD synthetic diamond component, wherein the central region has no cracks which intersect both external major faces of the free-standing non-planar polycrystalline CVD synthetic diamond component and extend greater than 2 mm in length.

Abstract: The present disclosure relates to substrates for use in microwave plasma reactors. Certain substrates include a cylindrical disc of a carbide forming refractory metal having a flat growth surface on which CVD diamond is to be grown and a flat supporting surface opposed to said growth surface. The cylindrical disc may have a diameter of 80 mm or more. The growth surface may have a flatness variation no more than 100 mm The supporting surface may have a flatness variation no more than 100 mm.

Abstract: A microwave plasma reactor for manufacturing synthetic diamond material via chemical vapour deposition, the microwave plasma reactor comprising: a plasma chamber; a substrate holder disposed in the plasma chamber for supporting a substrate on which the synthetic diamond material is to be deposited in use; a microwave coupling configuration for feeding microwaves from a microwave generator into the plasma chamber; and a gas flow system for feeding process gases into the plasma chamber and removing them therefrom; wherein the gas flow system comprises a gas inlet nozzle array comprising a plurality of gas inlet nozzles disposed opposite the substrate holder for directing process gases towards the substrate holder, the gas inlet nozzle array comprising: at least six gas inlet nozzles disposed in a substantially parallel or divergent orientation relative to a central axis of the plasma chamber; a gas inlet nozzle number density equal to or greater than 0.

Abstract: A microwave plasma reactor for manufacturing synthetic diamond material via chemical vapor deposition, the microwave plasma reactor comprising: a microwave generator configured to generate microwaves at a frequency f; a plasma chamber comprising a base, a top plate, and a side wall extending from said base to said top plate defining a resonance cavity for supporting a microwave resonance mode between the base and the top plate; a microwave coupling configuration for feeding microwaves from the microwave generator into the plasma chamber; a gas flow system for feeding process gases into the plasma chamber and removing them therefrom; a substrate holder disposed in the plasma chamber and comprising a supporting surface for supporting a substrate; and a substrate disposed on the supporting surface, the substrate having a growth surface on which the synthetic diamond material is to be deposited in use, wherein the substrate dimensions and location within the resonance cavity are selected to generate a localized a

Abstract: A microwave plasma reactor for manufacturing synthetic diamond material via chemical vapour deposition, the microwave plasma reactor comprising: a microwave generator configured to generate microwaves at a frequency f; a plasma chamber comprising a base, a top plate, and a side wall extending from said base to said top plate defining a resonance cavity for supporting a microwave resonance mode between the base and the top plate; a microwave coupling configuration for feeding microwaves from the microwave generator into the plasma chamber; a gas flow system for feeding process gases into the plasma chamber and removing them therefrom; a substrate holder disposed in the plasma chamber and comprising a supporting surface for supporting a substrate; and a substrate disposed on the supporting surface, the substrate having a growth surface on which the synthetic diamond material is to be deposited in use, wherein the substrate dimensions and location within the resonance cavity are selected to generate a localized

Abstract: A method of manufacturing a composite substrate for a semiconductor device, the method comprising: depositing silicon on a surface of a synthetic diamond wafer; and treating the synthetic diamond wafer to transform the deposited silicon into silicon carbide thus forming a layer of silicon carbide on the surface of the synthetic diamond wafer, wherein the synthetic diamond wafer is selected from one of: a single crystal diamond wafer; and a polycrystalline CVD diamond wafer having a nucleation face and a growth face wherein the nucleation face comprises smaller diamond grains than the growth face, and wherein if the synthetic diamond wafer is a polycrystalline CVD diamond wafer then the silicon carbide layer is formed on the growth face of the polycrystalline CVD diamond wafer.

Abstract: Electronic field effect devices, and methods of manufacture of these electronic field effect devices are disclosed. In particular, there is disclosed an electronic field effect device which has improved electrical properties due to the formation of a highly mobile two-dimensional charge-carrier gas in a simple structure formed from diamond in combination with polar materials.

Abstract: (EN): A microwave power delivery system for supplying microwave power to a plurality of microwave plasma reactors (8), the microwave power delivery system comprising: a tuner (14) configured to be coupled to a microwave source (4) and configured to match impedance of the plurality of microwave plasma reactors to that of the microwave source; and a waveguide junction (18) coupled to the tuner and configured to guide microwaves to and from the plurality of microwave plasma reactors, wherein the waveguide junction comprises four waveguide ports including a first port coupled to the tuner, second and third ports configured to be coupled to respective microwave plasma reactors, and a fourth port coupled to a microwave sink (20), wherein the waveguide junction is configured to evenly split microwave power input from the tuner through the first port between the second and third ports for providing microwave power to respective microwave plasma reactors, wherein the waveguide junction is configured to decouple the se

Abstract: Electronic field effect devices, and methods of manufacture of these electronic field effect devices are disclosed. In particular, there is disclosed an electronic field effect device which has improved electrical properties due to the formation of a highly mobile two-dimensional charge-carrier gas in a simple structure formed from diamond in combination with polar materials.

Abstract: A rigid three-dimensional component such as a speaker dome is formed of diamond, preferably fabricated to net shape by CVD diamond synthesis, and includes a coating on one or more major surfaces thereof. The coating is designed to enhance the performance and/or to alter the appearance of the component. In particular, the coating is designed to act as a damping medium and/or provide aesthetic qualities to the component.

Abstract: A single crystal diamond element having a convex surface is disclosed, the convex surface including a spherical segment for which the maximum peak to valley deviation from a perfect spherical surface is less than about 5 ?m. Alternatively or in addition, the RMS deviation from a perfect spherical surface may be less than about 500 nm, or the RMS roughness less than about 30 nm. A single crystal diamond element with a radius of curvature less than about 20 mm is also disclosed. In one aspect a single crystal diamond element having a conical half-angle greater than about 10° is described. The invention also provides a method for forming a rotationally symmetrical surface on a single crystal diamond element, comprising rotating the element about a first axis, applying a laser beam to the element in a direction perpendicular to the first axis, and translating the laser beam in two dimensions in a plane perpendicular to the direction of the beam.

Abstract: Electronic field effect devices, and methods of manufacture of these electronic field effect devices are disclosed. In particular, there is disclosed an electronic field effect device which has improved electrical properties due to the formation of a highly mobile two-dimensional charge-carrier gas in a simple structure formed from diamond in combination with polar materials.

Abstract: Electronic field effect devices, and methods of manufacture of these electronic field effect devices are disclosed. In particular, there is disclosed an electronic field effect device which has improved electrical properties due to the formation of a highly mobile two-dimensional charge-carrier gas in a simple structure formed from diamond in combination with polar materials.

Abstract: A high voltage diamond based switching device capable of sustaining high currents in the on state with a relatively low impedance and a relatively low optical switching flux, and capable of being switched off in the presence of the high voltage being switched. The device includes a diamond body having a Schottky barrier contact, held in reverse bias by the applied voltage to be switched, to an essentially intrinsic diamond layer or portion in the diamond body, a second metal contact, and an optical source or other illuminating or irradiating device such that when the depletion region formed by the Schottky contact to the intrinsic diamond layer is exposed to its radiation charge carriers are generated. Cain in the total number of charge carriers then occurs as a result of these charge carriers accelerating under the field within the intrinsic diamond layer and generating further carriers by assisted avalanche breakdown.