Provided are a high quality silicon carbide seed crystal, a silicon carbide crystal, a silicon carbide substrate, and a preparation method therefor. A high quality silicon carbide seed crystal is prepared, the dopant concentrations of a thermal insulation material, a graphite crucible, and a silicon carbide powder material are controlled, a specific crystal growth process and a wafer machining means are integrated, and a high quality silicon carbide substrate is obtained. The obtained silicon carbide substrate has a high crystalline quality and an extremely low amount of micropipes, screw dislocation density, and compound dislocation density; said substrate also has an extremely low p-type dopant concentration, exhibits superior electrical performance, and has a high surface quality.

A semiconductor substrate includes a first material layer made of a first material and including a plurality of protrusions, and a second material layer made of a second material different from the first material, filling spaces between the plurality of protrusions, and covering the plurality of protrusions. Each of the protrusions includes a tip and a plurality of facets converging at the tip, and adjacent facets of adjacent protrusions are in contact with each other.

A semiconductor substrate includes a first material layer made of a first material and including a plurality of protrusions, and a second material layer made of a second material different from the first material, filling spaces between the plurality of protrusions, and covering the plurality of protrusions. Each of the protrusions includes a tip and a plurality of facets converging at the tip, and adjacent facets of adjacent protrusions are in contact with each other.

A silicon carbide substrate has a first main surface and a second main surface opposite to the first main surface. The silicon carbide substrate includes screw dislocations and pits having a maximum diameter of 1 μm or more and 10 μm or less in a direction parallel to the first main surface. When the screw dislocations and the pits are observed in the first main surface, a percentage obtained by dividing a number of the pits by a number of the screw dislocations is 1% or less. A concentration of magnesium in the first main surface is less than 1×10.sup.11 atoms/cm.sup.2.

A silicon carbide substrate has a first main surface and a second main surface opposite to the first main surface. The silicon carbide substrate includes screw dislocations and pits having a maximum diameter of 1 μm or more and 10 μm or less in a direction parallel to the first main surface. When the screw dislocations and the pits are observed in the first main surface, a percentage obtained by dividing a number of the pits by a number of the screw dislocations is 1% or less. A concentration of magnesium in the first main surface is less than 1×10.sup.11 atoms/cm.sup.2.

The present disclosure relates to the field of manufacturing of silicon carbide (SiC) single crystal wafers, and discloses a stripping method and a stripping device for SiC single crystal wafers. The single crystal wafers obtained by the present disclosure have no damage layer or stress residue on surfaces or sub-surfaces, and are simple in operation and low in cost.

The present disclosure relates to the field of manufacturing of silicon carbide (SiC) single crystal wafers, and discloses a stripping method and a stripping device for SiC single crystal wafers. The single crystal wafers obtained by the present disclosure have no damage layer or stress residue on surfaces or sub-surfaces, and are simple in operation and low in cost.

A manufacturing method includes: (1) providing M-M′ nanowires, wherein M′ is at least one sacrificial metal different from M; and (2) subjecting the M-M′ nanowires to electrochemical de-alloying to form jagged M nanowires.

A manufacturing method includes: (1) providing M-M′ nanowires, wherein M′ is at least one sacrificial metal different from M; and (2) subjecting the M-M′ nanowires to electrochemical de-alloying to form jagged M nanowires.

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.