Provided is a surface treatment method for a SiC substrate (40), the method being capable of controlling whether to generate a step bunching or the type of step bunching that is generated. In the surface treatment method in which the surface of the SiC substrate (40) is etched by heating the SiC substrate (40) under Si vapor pressure, an etching mode and an etching depth which are determined at least on the basis of an etching rate, are controlled to etch the SiC substrate (40), so that a surface pattern of the SiC substrate (40) after etching treatment is controlled.

A silicon carbide substrate is composed of silicon carbide, and when a main surface thereof is etched with chlorine gas, the overall length of linear etch-pit groups observed in the main surface is equal to or less than the diameter of the substrate.

A silicon carbide substrate is composed of silicon carbide, and when a main surface thereof is etched with chlorine gas, the overall length of linear etch-pit groups observed in the main surface is equal to or less than the diameter of the substrate.

A method includes providing a p-type S/D epitaxial feature and an n-type source/drain (S/D) epitaxial feature, forming a semiconductor material layer over the n-type S/D epitaxial feature and the p-type S/D epitaxial feature, processing the semiconductor material layer with a germanium-containing gas, where the processing of the semiconductor material layer forms a germanium-containing layer over the semiconductor material layer, etching the germanium-containing layer, where the etching of the germanium-containing layer removes the germanium-containing layer formed over the n-type S/D epitaxial feature and the semiconductor material layer formed over the p-type S/D epitaxial feature, and forming a first S/D contact over the semiconductor material layer remaining over the n-type S/D epitaxial feature and a second S/D contact over the p-type S/D epitaxial feature. The semiconductor material layer may have a composition similar to that of the n-type S/D epitaxial feature.

A method includes providing a p-type S/D epitaxial feature and an n-type source/drain (S/D) epitaxial feature, forming a semiconductor material layer over the n-type S/D epitaxial feature and the p-type S/D epitaxial feature, processing the semiconductor material layer with a germanium-containing gas, where the processing of the semiconductor material layer forms a germanium-containing layer over the semiconductor material layer, etching the germanium-containing layer, where the etching of the germanium-containing layer removes the germanium-containing layer formed over the n-type S/D epitaxial feature and the semiconductor material layer formed over the p-type S/D epitaxial feature, and forming a first S/D contact over the semiconductor material layer remaining over the n-type S/D epitaxial feature and a second S/D contact over the p-type S/D epitaxial feature. The semiconductor material layer may have a composition similar to that of the n-type S/D epitaxial feature.

Provided are a method for preparing a vertical branched graphene comprising treating a pristine vertical graphene with an inert plasma in the absence of an introduced carbon source to develop a vertical branched graphene. The method may also include pre-treating a substrate surface with an inert plasma; depositing a pristine vertical graphene onto the substrate surface by contacting the substrate surface with a deposition plasma comprising a carbon source gas for a deposition period. Also provided are a vertical branched graphene attached to a substrate surface, the vertical branched graphene having a trunk portion extending from the substrate surface, said trunk possessing an increased degree of branching as the distance from the substrate surface increases; and a freestanding branched graphene with a proximal end and a distal end, the proximal end comprising a trunk portion, the trunk portion possessing and increased degree of branching as the distance from the proximal end increases and the distance to the distal end decreases.

A device includes a semiconductor substrate containing gallium nitride and having a crystal face inclined from 0.05° to 15° inclusive with respect to the c-plane. The semiconductor substrate includes an irregular portion on the crystal face, and the contact angle of pure water having a specific resistance of 18 MΩ.Math.cm or more on the surface of the irregular portion is 10° or less.

The present disclosure provides a method of fabricating a diamond membrane. The method comprises providing a substrate and a support structure. The substrate comprises a diamond material having a first surface and the substrate further comprises a sub-surface layer that is positioned below the first surface and has a crystallographic structure that is different to that of the diamond material. The sub-surface layer is positioned to divide the diamond material into first and second regions wherein the first region is positioned between the first surface and the sub-surface layer. The support structure also comprises a diamond material and is connected to, and covers a portion of, the first surface of the substrate. The method further comprises selectively removing the second region of the diamond material from the substrate by etching away at least a portion of the sub-surface layer of the substrate.

The present disclosure provides a method of fabricating a diamond membrane. The method comprises providing a substrate and a support structure. The substrate comprises a diamond material having a first surface and the substrate further comprises a sub-surface layer that is positioned below the first surface and has a crystallographic structure that is different to that of the diamond material. The sub-surface layer is positioned to divide the diamond material into first and second regions wherein the first region is positioned between the first surface and the sub-surface layer. The support structure also comprises a diamond material and is connected to, and covers a portion of, the first surface of the substrate. The method further comprises selectively removing the second region of the diamond material from the substrate by etching away at least a portion of the sub-surface layer of the substrate.

A trench MOS Schottky diode includes a first semiconductor layer including a Ga.sub.2O.sub.3-based single crystal, a second semiconductor layer that is a layer stacked on the first semiconductor layer, includes a Ga.sub.2O.sub.3-based single crystal, and includes a trench opened on a surface thereof opposite to the first semiconductor layer, an anode electrode formed on the surface of the second semiconductor layer, a cathode electrode formed on a surface of the first semiconductor layer, an insulating film covering the inner surface of the trench of the second semiconductor layer, and a trench electrode that is buried in the trench of the second semiconductor layer so as to be covered with the insulating film and is in contact with the anode electrode. The second semiconductor layer includes an insulating dry-etching-damaged layer with a thickness of not more than 0.8 μm in a region including the inner surface of the trench.