US 2026/0286570 A1Published application

Digallium trioxide single-crystal substrate, method of manufacturing digallium trioxide single crystal, and method of manufacturing digallium trioxide single-crystal substrate

AssigneeSumitomo Electric Industries, Ltd.

InventorsYukio ISHIKAWA, Keisuke TANIZAKI

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Abstract

A digallium trioxide single crystal substrate has a circular main surface, wherein the digallium trioxide single crystal substrate has a diameter of 100 mm or more, the main surface is a (001) plane of a digallium trioxide single crystal, the main surface has a central portion including a center of the main surface and an outer peripheral portion surrounding an outer periphery of the central portion, and first nanoindention hardnesses measured at nine positions on the main surface in accordance with a nanoindentation method using a Berkovich indenter are each 13 GPa to 20 GPa under a condition in which a maximum load is set to 10 mN and a load is applied such that a crossing angle between one side of an indention and a direction in which a direction of the digallium trioxide single crystal is projected on the main surface is 0° to 10°.

Claims7

Dependent claims

A digallium trioxide single-crystal substrate comprising a circular main surface,

wherein the digallium trioxide single-crystal substrate has a diameter of 100 mm or more,
the main surface is a (001) plane of a digallium trioxide single crystal constituting the digallium trioxide single-crystal substrate,
the main surface has a central portion including a center of the main surface and an outer peripheral portion surrounding an outer periphery of the central portion,
the outer peripheral portion is a chamfered region,
first nanoindentation hardnesses measured at nine positions on the main surface in accordance with a nanoindentation method using a Berkovich indenter are each 13 GPa to 20 GPa under a first condition in which a maximum load is set to 10 mN and a load is applied such that a crossing angle between one side of an indentation and a direction in which a [100] direction of the digallium trioxide single crystal is projected on the main surface is 0° to 10°, and
when a length from the center of the main surface to a boundary between the central portion and the outer peripheral portion is r, two axes passing through the center and orthogonal to each other on the main surface are an X-axis and a Y-axis, and the Y-axis is a b-axis of the digallium trioxide single crystal, coordinates (X, Y) of the X-axis and the Y-axis at the nine positions are (0, 0), (r-5, 0), (0, r-5), (−(r-5), 0), (0, −(r-5)), (r-1, 0), (0, r-1), (−(r-1), 0), and (0, −(r-1)), and units of r and X and Y in the coordinates (X, Y) are mm.

3 more elements

A method of manufacturing a digallium trioxide single crystal, the method comprising:

preparing a single crystal growth apparatus including at least a crucible having a cylindrical shape and a heating device disposed so as to surround an outer periphery of the crucible;
placing a seed crystal in a bottom portion of the crucible, and placing a digallium trioxide bulk body that is in a form of a lump, a plate-shaped member composed of pyrolytic boron nitride, and boron oxide in a solid state in that order above the seed crystal in the crucible;
by heating the crucible by the heating device to melt the digallium trioxide bulk body and a portion of the seed crystal, obtaining a digallium trioxide melt and bringing the digallium trioxide melt into contact with a remaining portion of the seed crystal;
and
obtaining the digallium trioxide single crystal by growing a crystal from the digallium trioxide melt on the remaining portion of the seed crystal,
wherein the bringing the digallium trioxide melt into contact with the remaining portion of the seed crystal includes disposing the plate-shaped member on the digallium trioxide melt and turning the boron oxide into liquid,
an atmosphere in which the obtaining the digallium trioxide single crystal is performed is an inert gas atmosphere,
the crucible includes a seed-crystal placing portion having a cylindrical shape, a diameter increasing portion connected to the seed-crystal placing portion, and a straight body portion connected to the diameter increasing portion,
the seed-crystal placing portion has a hollow portion that opens on a side connected to the diameter increasing portion and that is provided with a bottom wall on a side opposite to the diameter increasing portion,
the diameter increasing portion has a shape in which an area S of a cross section of the diameter increasing portion orthogonal to an axial direction of the crucible increases upward in the axial direction, and is connected to the seed-crystal placing portion on a small-diameter side of the diameter increasing portion,
the diameter increasing portion has three or four positions at each of which a ratio S/Z of the area S to a distance Z in the axial direction of the crucible from a connection point between the diameter increasing portion and the seed-crystal placing portion is 157.1 mm,
the straight body portion has a hollow cylindrical shape and is connected to a large-diameter side of the diameter increasing portion,
the plate-shaped member has a plurality of through-holes each extending through the plate-shaped member in a direction parallel to the axial direction in a state in which the plate-shaped member is disposed on the digallium trioxide melt,
an area proportion of the plurality of through-holes occupying a cross section of the plate-shaped member orthogonal to the axial direction is 0.12 to 0.28, and
a unit of the distance Z is mm, a unit of the area S is mm2, and a unit of S/Z is mm.

12 more elements

Dependencies are inferred from the claim text.