It is provided a seed crystal layer, composed of a group 13 nitride crystal selected from gallium nitride, aluminum nitride, indium nitride or the mixed crystals thereof, on an alumina layer on a single crystal substrate. By annealing under reducing atmosphere at a temperature of 950° C. or higher and 1200° C. or lower, convex-concave morphology is formed on a surface of the seed crystal layer so as to have an RMS value of 180 nm to 700 nm measured by an atomic force microscope. On the surface of the seed crystal layer, it is grown a group 13 nitride crystal layer composed of a group 13 nitride crystal selected from gallium nitride, aluminum nitride, indium nitride or the mixed crystals thereof.

A method includes a graphene precursor formation process of: heating a SiC substrate to sublimate Si atoms in a Si surface of the SiC substrate so that a graphene precursor is formed; and stopping the heating before the graphene precursor is covered with graphene. A SiC substrate to be treated in the graphene precursor formation process is provided with a step including a plurality of molecular layers. The step has a stepped structure in which a molecular layer whose C atom has two dangling bonds is disposed closer to the surface than a molecular layer whose C atom has one dangling bond.

A method includes a graphene precursor formation process of: heating a SiC substrate to sublimate Si atoms in a Si surface of the SiC substrate so that a graphene precursor is formed; and stopping the heating before the graphene precursor is covered with graphene. A SiC substrate to be treated in the graphene precursor formation process is provided with a step including a plurality of molecular layers. The step has a stepped structure in which a molecular layer whose C atom has two dangling bonds is disposed closer to the surface than a molecular layer whose C atom has one dangling bond.

Provided is a semiconductor substrate manufacturing device which is capable of uniformly heating the surface of a semiconductor substrate that has a relatively large diameter or major axis. The semiconductor substrate manufacturing device includes a container body for accommodating a semiconductor substrate and a heating furnace that has a heating chamber which accommodates the container body, and the heating furnace has a heating source in a direction intersecting the semiconductor substrate to be disposed inside the heating chamber.

Provided is a semiconductor substrate manufacturing device which is capable of uniformly heating the surface of a semiconductor substrate that has a relatively large diameter or major axis. The semiconductor substrate manufacturing device includes a container body for accommodating a semiconductor substrate and a heating furnace that has a heating chamber which accommodates the container body, and the heating furnace has a heating source in a direction intersecting the semiconductor substrate to be disposed inside the heating chamber.

A method of manufacturing a diamond substrate includes: forming an ion implantation layer at a side of a main surface of a diamond seed substrate by implanting ions into the main surface of the diamond seed substrate; producing a diamond structure by growing a diamond growth layer by a vapor phase synthesis method on the main surface of the diamond seed substrate, after implanting the ions; and performing heat treatment on the diamond structure. The performed heat treatment causes the diamond structure to be separated along the ion implantation layer into a first structure including the diamond seed substrate and failing to include the diamond growth layer, and a diamond substrate including the diamond growth layer. Thus, the method of manufacturing a diamond substrate is provided that enables a diamond substrate with a large area to be manufactured in a short time and at a low cost.

A method of manufacturing a diamond substrate includes: forming an ion implantation layer at a side of a main surface of a diamond seed substrate by implanting ions into the main surface of the diamond seed substrate; producing a diamond structure by growing a diamond growth layer by a vapor phase synthesis method on the main surface of the diamond seed substrate, after implanting the ions; and performing heat treatment on the diamond structure. The performed heat treatment causes the diamond structure to be separated along the ion implantation layer into a first structure including the diamond seed substrate and failing to include the diamond growth layer, and a diamond substrate including the diamond growth layer. Thus, the method of manufacturing a diamond substrate is provided that enables a diamond substrate with a large area to be manufactured in a short time and at a low cost.

A processed wafer includes an outer surface, and a treated portion having a depth of 0 to 50 μm measured from the outer surface. At least a part of the treated portion has an oxygen concentration of less than 13 wt %. A method for processing a wafer includes the steps of: applying a reducing medium on the wafer, the reducing medium is in powder form and including a reducing agent, and at least one of a catalyst and a releasing agent; subjecting the wafer to a reduction reaction at a temperature below Curie temperature of the and under a non-oxidizing atmosphere so as to obtain the aforesaid processed wafer.

A processed wafer includes an outer surface, and a treated portion having a depth of 0 to 50 μm measured from the outer surface. At least a part of the treated portion has an oxygen concentration of less than 13 wt %. A method for processing a wafer includes the steps of: applying a reducing medium on the wafer, the reducing medium is in powder form and including a reducing agent, and at least one of a catalyst and a releasing agent; subjecting the wafer to a reduction reaction at a temperature below Curie temperature of the and under a non-oxidizing atmosphere so as to obtain the aforesaid processed wafer.

A high-temperature forming device for imperfect single-crystal wafers used for a neutron monochromator includes a heating electric furnace, a temperature control system, a die system, a loading system, a vacuum protection system, and an auxiliary system. Where a furnace mouth of the heating electric furnace faces downwards, the heating electric furnace can be lifted vertically or a hearth of the heating electric furnace can be opened and closed. A vacuum protection cavity is formed by a glass cover and a blocking flange, a through hole is formed in one end of the glass cover, and the other end of the glass cover is closed. An operation opening is formed in the glass cover, the die system includes an upper die, a middle die, and a lower die, the middle die is a composite die.