A synthetic single crystal diamond contains nitrogen atoms at a concentration of more than 600 ppm and 1500 ppm or less, and the nitrogen atoms do not include any isolated substitutional nitrogen atom.

A wafer production method for producing a wafer from a lithium tantalate ingot includes a step of irradiating, from an end face of a lithium tantalate ingot which is a 42-degree rotation Y cut ingot having an orientation flat formed in parallel to a Y axis, a laser beam of a wavelength having transparency to lithium tantalate with a focal point of the laser beam positioned in the inside of the ingot to form a modified layer in the inside of the ingot while the ingot is fed for processing, and a step of applying external force to the ingot to peel off a plate-shaped material from the ingot to produce a wafer. At the step of forming a modified layer, the ingot is relatively fed for processing in a direction parallel or perpendicular to the orientation flat.

A wafer production method for producing a wafer from a lithium tantalate ingot includes a step of irradiating, from an end face of a lithium tantalate ingot which is a 42-degree rotation Y cut ingot having an orientation flat formed in parallel to a Y axis, a laser beam of a wavelength having transparency to lithium tantalate with a focal point of the laser beam positioned in the inside of the ingot to form a modified layer in the inside of the ingot while the ingot is fed for processing, and a step of applying external force to the ingot to peel off a plate-shaped material from the ingot to produce a wafer. At the step of forming a modified layer, the ingot is relatively fed for processing in a direction parallel or perpendicular to the orientation flat.

Provided is a synthetic single crystal diamond containing nitrogen atoms at a concentration of more than 600 ppm and 1500 ppm or less. The Raman shift (cm.sup.1) of a peak in a primary Raman scattering spectrum of the synthetic single crystal diamond and the Raman shift (cm.sup.1) of a peak in a primary Raman scattering spectrum of a synthetic type IIa single crystal diamond containing nitrogen atoms at a content of 1 ppm or less satisfy the following expression (1):

0.10(1).

Provided is a synthetic single crystal diamond containing nitrogen atoms at a concentration of more than 600 ppm and 1500 ppm or less. The Raman shift (cm.sup.1) of a peak in a primary Raman scattering spectrum of the synthetic single crystal diamond and the Raman shift (cm.sup.1) of a peak in a primary Raman scattering spectrum of a synthetic type IIa single crystal diamond containing nitrogen atoms at a content of 1 ppm or less satisfy the following expression (1):

0.10(1).

A SiC member includes: a substrate having a reference hole in a front-back direction; and first and second SiC coats. The first SiC coat has a first hole connected to the reference hole in the front-back direction, a first region extending around the first hole to form its inner circumferential surface, and a second region extending around the first region adjacently to the first region, the second SiC coat has a second hole connected to the first hole in the front-back direction, a third region extending around the second hole to form its inner circumferential surface, and a fourth region extending around the third region adjacently to the third region, the first region has a crystal structure containing crystals grown in a first direction obliquely crossing the front-back direction, and the second, third and fourth regions have crystal structures containing crystals grown in a second direction along the front-back direction.

A method for manufacturing a peeled substrate has a laser condensing step for focusing laser light at a prescribed depth from the surface of a substrate and a positioning step for moving and positioning a laser condenser relative to the substrate, the method involving forming a processed layer in the substrate. The laser condensing step includes a laser light adjustment step in which a diffraction optical element is used to branch the laser light into a plurality of branched laser beams, and at least one of the branched laser beams is branched such that the intensity thereof differs from the other branched laser beams. The processed layer is elongated using the branched laser beam having a relatively high intensity among the plurality of branched laser beams to process the substrate, and the elongation of the processed layer is restrained using the branched laser beams having a relatively low intensity.

A method for manufacturing a peeled substrate has a laser condensing step for focusing laser light at a prescribed depth from the surface of a substrate and a positioning step for moving and positioning a laser condenser relative to the substrate, the method involving forming a processed layer in the substrate. The laser condensing step includes a laser light adjustment step in which a diffraction optical element is used to branch the laser light into a plurality of branched laser beams, and at least one of the branched laser beams is branched such that the intensity thereof differs from the other branched laser beams. The processed layer is elongated using the branched laser beam having a relatively high intensity among the plurality of branched laser beams to process the substrate, and the elongation of the processed layer is restrained using the branched laser beams having a relatively low intensity.

Methods are provided for separating a crystalline film from its main body. The method uses ion implantation to generate an ion damaged layer underneath the surface of the crystalline object. The ion damage changes the crystal structure of the ion damaged layer, so it will have different optical transmittance and absorption characteristics from the undamaged part of the crystalline object. A laser beam with a wavelength that is higher than the absorption edge of the non-ion damaged material, but within the absorption range of the ion damaged material is irradiated at or past the ion damaged layer, causing further damage to the ion damaged layer. The film can then be separated from the main body of the crystalline object.

Methods are provided for separating a crystalline film from its main body. The method uses ion implantation to generate an ion damaged layer underneath the surface of the crystalline object. The ion damage changes the crystal structure of the ion damaged layer, so it will have different optical transmittance and absorption characteristics from the undamaged part of the crystalline object. A laser beam with a wavelength that is higher than the absorption edge of the non-ion damaged material, but within the absorption range of the ion damaged material is irradiated at or past the ion damaged layer, causing further damage to the ion damaged layer. The film can then be separated from the main body of the crystalline object.