A method of fabricating plates of super-hard material and cutting techniques suitable for such a method. A method of fabricating a plate (14) of super-hard material, the method comprising: • providing a substrate (4) have a lateral dimension of at least 40 mm; • growing a layer of super-hard material on the substrate (4) using a chemical vapour deposition process; and • slicing one or more plates (14) of super-hard material from the substrate using a collimated cutting beam (8), the or each plate of super-hard material (14) having a lateral dimension of at least 40 mm, wherein the collimated cutting beam (8) is collimated with a half angle divergence of no more than 5 degrees.

A method of fabricating plates of super-hard material and cutting techniques suitable for such a method. A method of fabricating a plate (14) of super-hard material, the method comprising: • providing a substrate (4) have a lateral dimension of at least 40 mm; • growing a layer of super-hard material on the substrate (4) using a chemical vapour deposition process; and • slicing one or more plates (14) of super-hard material from the substrate using a collimated cutting beam (8), the or each plate of super-hard material (14) having a lateral dimension of at least 40 mm, wherein the collimated cutting beam (8) is collimated with a half angle divergence of no more than 5 degrees.

A device includes a semiconductor substrate containing gallium nitride and having a crystal face inclined from 0.05° to 15° inclusive with respect to the c-plane. The semiconductor substrate includes an irregular portion on the crystal face, and the contact angle of pure water having a specific resistance of 18 MΩ.Math.cm or more on the surface of the irregular portion is 10° or less.

A device includes a semiconductor substrate containing gallium nitride and having a crystal face inclined from 0.05° to 15° inclusive with respect to the c-plane. The semiconductor substrate includes an irregular portion on the crystal face, and the contact angle of pure water having a specific resistance of 18 MΩ.Math.cm or more on the surface of the irregular portion is 10° or less.

A high-pressure high-temperature, HPHT, diamond tool piece and a method of producing an HPHT diamond tool piece. At least a portion of the HPHT diamond tool piece comprises an aggregated nitrogen centre to C-nitrogen centre ratio of greater than 30%. The method includes irradiating an HPHT diamond material to introduce vacancies in the diamond crystal lattice, annealing the HPHT diamond material such that at least a portion of the HPHT diamond material comprises an aggregated nitrogen centre to C-nitrogen centre ratio of greater than 30%, and processing the HPHT diamond material to form an HPHT diamond tool piece.

A high-pressure high-temperature, HPHT, diamond tool piece and a method of producing an HPHT diamond tool piece. At least a portion of the HPHT diamond tool piece comprises an aggregated nitrogen centre to C-nitrogen centre ratio of greater than 30%. The method includes irradiating an HPHT diamond material to introduce vacancies in the diamond crystal lattice, annealing the HPHT diamond material such that at least a portion of the HPHT diamond material comprises an aggregated nitrogen centre to C-nitrogen centre ratio of greater than 30%, and processing the HPHT diamond material to form an HPHT diamond tool piece.

A wafer is produced from an ingot by confirming whether or not an inclined c-axis of the ingot and a second orientation flat of the ingot are perpendicular to each other, and detecting a processing feed direction perpendicular to the direction in which the c-axis is inclined. The method includes performing sampling irradiation of the ingot with a laser beam, along a direction parallel to the second orientation flat and a plurality of directions inclined clockwise and counterclockwise by respective predetermined angles from the second orientation flat, thereby forming a plurality of sampled reduced strength areas in the ingot; measuring the number of nodes which exist per unit length on each of the sampled reduced strength areas, and determining a direction in which the sampled reduced strength area where the measured number of nodes is zero extends as a processing feed direction.

A wafer is produced from an ingot by confirming whether or not an inclined c-axis of the ingot and a second orientation flat of the ingot are perpendicular to each other, and detecting a processing feed direction perpendicular to the direction in which the c-axis is inclined. The method includes performing sampling irradiation of the ingot with a laser beam, along a direction parallel to the second orientation flat and a plurality of directions inclined clockwise and counterclockwise by respective predetermined angles from the second orientation flat, thereby forming a plurality of sampled reduced strength areas in the ingot; measuring the number of nodes which exist per unit length on each of the sampled reduced strength areas, and determining a direction in which the sampled reduced strength area where the measured number of nodes is zero extends as a processing feed direction.

Provided are a diamond composite body capable of shortening a separation time for separating a substrate and a diamond layer, the substrate, and a method for manufacturing a diamond, as well as a diamond obtained from the diamond composite body and a tool including the diamond. The diamond composite body includes a substrate including a diamond seed crystal and having grooves in a main surface, a diamond layer formed on the main surface of the substrate, and a non-diamond layer formed on a substrate side at a constant depth from an interface between the substrate and the diamond layer.

Provided are a diamond composite body capable of shortening a separation time for separating a substrate and a diamond layer, the substrate, and a method for manufacturing a diamond, as well as a diamond obtained from the diamond composite body and a tool including the diamond. The diamond composite body includes a substrate including a diamond seed crystal and having grooves in a main surface, a diamond layer formed on the main surface of the substrate, and a non-diamond layer formed on a substrate side at a constant depth from an interface between the substrate and the diamond layer.