A laser processing apparatus for producing a GaN wafer from a GaN ingot includes a laser beam irradiating unit configured to apply a laser beam having a wavelength capable of passing through the GaN ingot held by a chuck table. The laser beam irradiating unit includes a laser oscillator configured to oscillate the laser beam. The laser oscillator includes a seeder configured to oscillate a high-frequency pulsed laser, a thinning-out unit configured to thin out high-frequency pulses oscillated by the seeder at a predetermined repetition frequency, and generate one burst pulse with a plurality of high-frequency pulses as sub-pulses, and an amplifier configured to amplify the generated burst pulse.

A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an a-axis direction comprising a 0.15° or greater miscut angle towards the a-axis direction and a less than 30° miscut angle towards the a-axis direction.

A substrate includes a support structure comprising a polycrystalline ceramic core, a first adhesion layer encapsulating the polycrystalline ceramic core, a barrier layer encapsulating the first adhesion layer, a second adhesion layer coupled to the barrier layer, and a conductive layer coupled to the second adhesion layer. The substrate also includes a bonding layer coupled to the support structure, a substantially single crystal silicon layer coupled to the bonding layer, and an epitaxial semiconductor layer coupled to the substantially single crystal silicon layer.

A method for preparing a self-supporting substrate includes: preparing a thin film base structure including a first substrate layer, a thin film layer and a second substrate layer stacked in sequence; removing the first substrate layer from the thin film layer; continuing to grow a material the same as that of the thin film layer on a side of the thin film layer far away from the second substrate layer to prepare a thick film layer; and removing the second substrate layer from the thick film layer and remaining the thick film layer. In the method, a thin film may be grown on a substrate that has a larger diameter, and a thinness of the thin film will not cause the thin film and/or the substrate to crack. Therefore, a thin film that has a large diameter may be obtained so as to obtain a large-sized self-supporting thick film substrate.

Provides is a C-plane GaN substrate which, although formed from a GaN crystal grown so that surface pits are generated, is free from any inversion domain, and moreover, has a low spiral dislocation density in a gallium polar surface. Provides is a C-plane GaN substrate wherein: the substrate comprises a plurality of facet growth areas each having a closed ring outline-shape on a gallium polar surface; the spiral dislocation density is less than 1×10.sup.6 cm.sup.−2 anywhere on the gallium polar surface; and the substrate is free from any inversion domain. The C-plane GaN substrate may comprise a high dislocation density part having a dislocation density of more than 1×10.sup.7 cm.sup.−2 and a low dislocation density part having a dislocation density of less than 1×10.sup.6 cm.sup.−2 on the gallium polar surface.

A gallium nitride substrate comprising a first main surface and a second main surface opposite thereto, wherein the first main surface is a non-polar or semi-polar plane, a dislocation density measured by a room-temperature cathode luminescence method in the first main surface is 1×10.sup.4 cm.sup.−2 or less, and an averaged dislocation density measured by a room-temperature cathode luminescence method in an optional square region sizing 250 μm×250 μm in the first main plan is 1×10.sup.6 cm.sup.−2 or less.

A self-supporting substrate includes a first nitride layer grown by hydride vapor deposition method or ammonothermal method and comprising a nitride of one or more element selected from the group consisting of gallium, aluminum and indium; and a second nitride layer grown by a sodium flux method on the first nitride layer and comprising a nitride of one or more element selected from the group consisting of gallium, aluminum and indium. The first nitride layer includes a plurality of single crystal grains arranged therein and being extended between a pair of main faces of the first nitride layer. The second nitride layer includes a plurality of single crystal grains arranged therein and being extended between a pair of main faces of the second nitride layer. The first nitride layer has a thickness larger than a thickness of the second nitride layer.

A new GaN single crystal is provided. A GaN single crystal according to the present embodiment comprises a gallium polar surface which is a main surface on one side and a nitrogen polar surface which is a main surface on the opposite side, wherein on the gallium polar surface is found at least one square area, an outer periphery of which is constituted by four sides each with a length of 2 mm or more, and, when the at least one square are is divided into a plurality of sub-areas each of which is a square of 100 μm×100 μm, pit-free areas account for 80% or more of the sub-areas.

In a manufacturing method of a semiconductor element of the present disclosure, a first semiconductor part (SL1) includes a protruding portion (TS) protruding toward an underlying substrate (UK), the protruding portion contains a nitride semiconductor, the protruding portion and the underlying substrate are bonded to each other, a semiconductor substrate (HK) includes a hollow portion (TK) located between the underlying substrate and the first semiconductor part, the hollow portion is in contact with a side surface of the protruding portion and communicates with the outside of the semiconductor substrate, and the protruding portion (TS) is irradiated with the laser beam (LZ) before the first semiconductor part is separated from the semiconductor substrate.

Embodiments of the present disclosure include techniques related to techniques for processing materials for manufacture of group-III metal nitride and gallium based substrates. More specifically, embodiments of the disclosure include techniques for substrates with a controlled oxygen gradient using a combination of processing techniques. Merely by way of example, the disclosure can be applied to growing crystals of GaN, AlN, InN, InGaN, AlGaN, and AlInGaN, and others for manufacture of bulk or patterned substrates. Such bulk or patterned substrates can be used for a variety of applications including optoelectronic and electronic devices, lasers, light emitting diodes, solar cells, photo electrochemical water splitting and hydrogen generation, photodetectors, integrated circuits, and transistors, and others.