CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 37 U.S.C. § 371 to International Patent Application No. PCT/JP2020/011151, filed Mar. 13, 2020, which claims priority to and the benefit of Japanese Patent Application Nos. 2019-086052, filed on Apr. 26, 2019, and 2019-113773, filed on Jun. 19, 2019. The contents of these applications are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to a structure manufacturing method and an intermediate structure.

BACKGROUND ART

Group III nitrides such as gallium nitride (GaN) are used as materials for manufacturing semiconductor devices such as light emitting devices and transistors.

Photoelectrochemical (PEC) etching has been proposed as an etching technique for forming various structures on group III nitrides such as GaN (see, for example, Non-Patent Document 1). The PEC etching is wet etching with less damage than general dry etching, and is preferable because an apparatus is simple, compared to special dry etching with less damage such as neutral particle beam etching (see, for example, Non-Patent Document 2) and atomic layer etching (see, for example, Non-Patent Document 3).

CITATION LIST

Non-Patent Documents

Non-Patent Document 1: J. Murata et at, “Photo-electrochemical etching of free-standing GaN wafer surfaces grown by hydride vapor phase epitaxy”, Electrochimica Acta 171 (2015) 89-95Non-Patent Document 2: S. Samukawa, JJAP, 45 (2006) 2395.Non-Patent Document 3: T. Faraz, ECS J. Solid Stat. Scie. & Technol., 4, N5023 (2015).

SUMMARY OF INVENTION

Technical Problem

An object of the present invention is to provide a technique for favorably advancing PEC etching of group III nitrides.

Solution to Problem

According to an aspect of the present invention, there is provided a structure manufacturing method, including:

preparing a treatment object that includes an etching target having a surface to be etched comprising a conductive group III nitride and a region to be etched located on the surface to be etched, a conductive member that is provided so as to be in contact with at least a portion of a surface of a conductive region of the etching target that is electrically connected to the region to be etched, and a mask formed on the surface to be etched and comprising a non-conductive material; and

etching the group III nitride that constitutes the region to be etched by immersing the treatment object in an alkaline or acidic etching solution containing peroxodisulfate ions as an oxidizing agent that accepts electrons, and irradiating the surface to be etched with light through the etching solution in a state where the region to be etched and the conductive member are in contact with the etching solution,

wherein an edge that defines the region to be etched is constituted by an edge of the mask without including an edge of the conductive member.

According to another aspect of the present invention, there is provided an intermediate structure, including:

an etching target having a surface to be etched comprising a conductive group III nitride and a region to be etched located on the surface to be etched;

a conductive member that is provided so as to be in contact with at least a portion of a surface of a conductive region of the etching target that is electrically connected to the region to be etched; and

a mask formed on the surface to be etched and comprising a non-conductive material,

wherein the intermediate structure is immersed in an alkaline or acidic etching solution containing peroxodisulfate ions as an oxidizing agent that accepts electrons, in a state where the region to be etched is in contact with the conductive member, and

an edge that defines the region to be etched is constituted by an edge of the mask without including an edge of the conductive member.

Advantageous Effects of Invention

There is provided a technique for favorably advancing PEC etching of group III nitrides.

