Abstract: A method of manufacturing a transistor, typically a MESFET, includes providing a substrate including single crystal diamond material having a growth surface on which further layers of diamond material can be deposited. The substrate is preferably formed by a CVD process and has high purity. The growth surface has a root-mean-square roughness of 3 nm or less, or is free of steps or protrusions larger than 3 nm. Further diamond layers are deposited on the growth surface to define the active regions of the transistor. An optional n+ shielding layer can be formed in or on the substrate, following which an additional layer of high purity diamond is deposited. A layer of intrinsic diamond may be formed directly on the upper surface of the high purity layer, followed by a boron doped (“delta doped”) layer. A trench is formed in the delta doped layer to define a gate region.

Abstract: The invention relates to a method of manufacture of a substrate for fabrication of semiconductor layers or devices, comprising the steps of providing a wafer of silicon including at least one first surface suitable for use as a substrate for CVD diamond synthesis, growing a layer of CVD diamond of predetermined thickness and having a growth face onto the first surface of the silicon wafer, reducing the thickness of the silicon wafer to a predetermined level, and providing a second surface on the silicon wafer that is suitable for further synthesis of at least one semiconductor layer suitable for use in electronic devices or synthesis of electronic devices on the second surface itself and to a substrate suitable for GaN device growth consisting of a CVD diamond layer intimately attached to a silicon surface.

Abstract: A tiled array of diamond plates, which is suitable for wafer scale processing, for example, in the manufacture of electronic or other device structures on the diamond plates. The diamond plates are fixed to a support layer, preferably a polycrystalline diamond support layer, in a substantially planar arrangement such that at least one of the major surfaces of the respective fixed diamond plates defines a fabrication surface that is exposed for further processing. The support layer may be a backing layer, in which case only one of the major faces of the diamond substrate is exposed for further processing, or may extend between respective diamond substrates such that both major surfaces are exposed for further processing.

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 method of producing a diamond coated surface on a substrate. A surface of the substrate is prepared by exposing it to a power beam, such as an electron beam, to increase the surface area and surface roughness. Such preparation may also provide the surface with three dimensional features onto which a diamond layer can adhere and mechanically lock. Adhesion of a diamond layer applied to the prepared surface is increased.

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: The invention relates to a method of manufacture of a substrate for fabrication of semi-conductor layers or devices, comprising the steps of providing a wafer of silicon including at least one first surface suitable for use as a substrate for CVD diamond synthesis, growing a layer of CVD diamond of predetermined thickness and having a growth face onto the first surface of the silicon wafer, reducing the thickness of the silicon wafer to a predetermined level, and providing a second surface on the silicon wafer that is suitable for further synthesis of at least one semiconductor layer suitable for use in electronic devices or synthesis of electronic devices on the second surface itself and to a substrate suitable for GaN device growth consisting of a CVD diamond layer intimately attached to a silicon surface.

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 fast heating cathode comprises a layer of diamond, a thermionic emitting element in thermal contact with a surface of the diamond layer and means to heat the diamond layer.

Abstract: A component comprises a silicon carbide substrate (10), a layer (14) of CVD diamond on a surface (12) of the substrate, and a smooth surface (14a) on the CVD diamond layer (14) which is a non-planar bearing or wear-resistant surface for the component.

Abstract: A fast heating cathode comprises a layer of diamond, a thermionic emitting element in thermal contact with a surface of the diamond layer and means to heat the diamond layer.

Abstract: A method of bonding a diamond compact comprising a polycrystalline mass of diamond and a bonding phase which contains free-silicon to a substrate is provided. The method includes the steps of contacting a surface of the compact with carbon or nitrogen or a mixture thereof under conditions suitable to cause free-silicon in the surface to react with the carbon and/or nitrogen and thereafter bonding that surface to the substrate, preferably by means of a braze. In a preferred form of the invention, the surface which is bonded to the substrate is acid cleaned after contact of that surface with carbon or nitrogen or a mixture thereof.

Abstract: A surface of a diamond, particularly a diamond window, is treated by depositing a layer of a carbide-forming metal such as titanium, on the surface and thereafter removing the layer. The treatment has the effect of passivating stress surface defects in the diamond such as grain boundaries, twin defects and polishing damage.