An object is to provide a SiC wafer in which a detection rate of an optical sensor can improved and a SiC wafer manufacturing method.

The method includes: a satin finishing process S141 of satin-finishing at least a back surface 22 of a SiC wafer 20; an etching process 21 of etching at least the back surface 22 of the SiC wafer 20 by heating under Si vapor pressure after the satin finishing process S141; and a mirror surface processing process S31 of mirror-processing a main surface 21 of the SiC wafer 20 after the etching process S21. Accordingly, it is possible to obtain a SiC wafer having the mirror-finished main surface 21 and the satin-finished back surface 22.

An object is to provide a SiC wafer in which a detection rate of an optical sensor can improved and a SiC wafer manufacturing method.

The method includes: a satin finishing process S141 of satin-finishing at least a back surface 22 of a SiC wafer 20; an etching process 21 of etching at least the back surface 22 of the SiC wafer 20 by heating under Si vapor pressure after the satin finishing process S141; and a mirror surface processing process S31 of mirror-processing a main surface 21 of the SiC wafer 20 after the etching process S21. Accordingly, it is possible to obtain a SiC wafer having the mirror-finished main surface 21 and the satin-finished back surface 22.

A diamond comprising of: at least one surface; and a plurality of nanostructures formed on the at least one surface of the diamond, wherein the plurality of nanostructures generates one or more structural colours on the surface of the diamond.

A diamond comprising of: at least one surface; and a plurality of nanostructures formed on the at least one surface of the diamond, wherein the plurality of nanostructures generates one or more structural colours on the surface of the diamond.

Forming a two-dimensional Janus layer includes forming a layer of MX.sub.2, where M is a transition metal and X is a first chalcogen, plasma etching the layer of MX.sub.2 to remove X from the top layer, thereby yielding an etched layer, and contacting the etched layer with a second chalcogen Y. The second chalcogen is different than the first chalcogen, resulting in a two-dimensional Janus layer including MXY.

A hydrogen fluoride vapor phase corrosion method comprises: introducing a prescribed vaporized organic liquid into a reaction chamber after a vapor phase hydrogen fluoride containing water reacts, in the reaction chamber, with a wafer; the prescribed vaporized organic liquid, and the water remaining on a surface of the wafer form an azeotropic mixture; and evaporating or volatilizing the azeotropic mixture from the surface of the wafer to carry it out.

A single crystal CVD diamond material is disclosed, the material comprising a total nitrogen concentration of at least 3 ppm as measured by secondary ion mass spectrometry (SIMS); and a low optical birefringence such that in a sample of the single crystal CVD diamond material having an area of at least 1.3 mm×1.3 mm, and measured using a pixel size of area in a range 1×1 μm.sup.2 to 20×20 μm.sup.2, a maximum value of Δn.sub.[average] does not exceed 1.5×10.sup.−4, where Δn.sub.[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. A method of making the material is also disclosed.

A single crystal CVD diamond material is disclosed, the material comprising a total nitrogen concentration of at least 3 ppm as measured by secondary ion mass spectrometry (SIMS); and a low optical birefringence such that in a sample of the single crystal CVD diamond material having an area of at least 1.3 mm×1.3 mm, and measured using a pixel size of area in a range 1×1 μm.sup.2 to 20×20 μm.sup.2, a maximum value of Δn.sub.[average] does not exceed 1.5×10.sup.−4, where Δn.sub.[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. A method of making the material is also disclosed.

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 μm.sup.2 to 20×20 μm.sup.2, a maximum value of Δn.sub.[average] does not exceed 1.5×10.sup.−4 for the one or more regions of low optical birefringence, where Δn.sub.[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, Δn.sub.[average] is greater than 1.5×10.sup.−4 and less than 3×10.sup.−3; and is wherein every 1.3 mm×1.3 mm area of the sample of the single crystal CVD diamond material comprises at least one of said regions of high optical birefringence. There is also described a method of making the CVD diamond material.

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 μm.sup.2 to 20×20 μm.sup.2, a maximum value of Δn.sub.[average] does not exceed 1.5×10.sup.−4 for the one or more regions of low optical birefringence, where Δn.sub.[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, Δn.sub.[average] is greater than 1.5×10.sup.−4 and less than 3×10.sup.−3; and is wherein every 1.3 mm×1.3 mm area of the sample of the single crystal CVD diamond material comprises at least one of said regions of high optical birefringence. There is also described a method of making the CVD diamond material.