A method for forming semiconductor device includes providing a semiconductor substrate having an initial surface oxygen concentration in a surface region of less than 610.sup.17 cm.sup.3, forming an epitaxial layer on a first side of the semiconductor substrate, and implanting dopants into the epitaxial layer. An optional thermal anneal is carried out prior to forming the epitaxial layer and/or a thermal treatment is carried out after implanting dopants.

A method for forming semiconductor device includes providing a semiconductor substrate having an initial surface oxygen concentration in a surface region of less than 610.sup.17 cm.sup.3, forming an epitaxial layer on a first side of the semiconductor substrate, and implanting dopants into the epitaxial layer. An optional thermal anneal is carried out prior to forming the epitaxial layer and/or a thermal treatment is carried out after implanting dopants.

A Ga.sub.2O.sub.3-based semiconductor device includes a Ga.sub.2O.sub.3-based crystal layer including a donor, and an N-doped region formed in at least a part of the Ga.sub.2O.sub.3-based crystal layer.

A composite diamond body includes a diamond base material and a stable layer disposed on the diamond base material. The stable layer may have a thickness of 0.001 m or more and less than 10 m, and may include a plurality of layers. A composite diamond tool includes the composite diamond body. There are thus provided highly wear-resistant composite diamond body and composite diamond tool that are even applicable to mirror-finish planarization of a workpiece which reacts with diamond to cause the diamond to wear.

A composite diamond body includes a diamond base material and a stable layer disposed on the diamond base material. The stable layer may have a thickness of 0.001 m or more and less than 10 m, and may include a plurality of layers. A composite diamond tool includes the composite diamond body. There are thus provided highly wear-resistant composite diamond body and composite diamond tool that are even applicable to mirror-finish planarization of a workpiece which reacts with diamond to cause the diamond to wear.

A method of manufacturing a diamond by a vapor phase synthesis method includes: preparing a substrate including a diamond seed crystal; forming a light absorbing layer lower in optical transparency than the substrate by performing ion implantation into the substrate, the light absorbing layer being formed at a predetermined depth from a main surface of the substrate; growing a diamond layer on the main surface of the substrate by the vapor phase synthesis method; and separating the diamond layer from the substrate by applying light from a main surface of at least one of the diamond layer and the substrate to allow the light absorbing layer to absorb the light and cause the light absorbing layer to be broken up.

A method of manufacturing a diamond by a vapor phase synthesis method includes: preparing a substrate including a diamond seed crystal; forming a light absorbing layer lower in optical transparency than the substrate by performing ion implantation into the substrate, the light absorbing layer being formed at a predetermined depth from a main surface of the substrate; growing a diamond layer on the main surface of the substrate by the vapor phase synthesis method; and separating the diamond layer from the substrate by applying light from a main surface of at least one of the diamond layer and the substrate to allow the light absorbing layer to absorb the light and cause the light absorbing layer to be broken up.

Using processes disclosed herein, materials and structures are created and used. For example, processes can include melting boron nitride or amorphous carbon into an undercooled state followed by quenching. Exemplary new materials disclosed herein can be ferromagnetic and/or harder than diamond. Materials disclosed herein may include dopants in concentrations exceeding thermodynamic solubility limits. A novel phase of solid carbon has structure different than diamond and graphite.

Using processes disclosed herein, materials and structures are created and used. For example, processes can include melting boron nitride or amorphous carbon into an undercooled state followed by quenching. Exemplary new materials disclosed herein can be ferromagnetic and/or harder than diamond. Materials disclosed herein may include dopants in concentrations exceeding thermodynamic solubility limits. A novel phase of solid carbon has structure different than diamond and graphite.

An epitaxy substrate and a method of manufacturing the same are provided. The epitaxy substrate includes a silicon substrate and a silicon carbide layer. The silicon substrate has a first surface and a second surface opposite to each other, and the first surface is an epitaxy surface. The silicon carbide layer is located in the silicon substrate, and a distance between the silicon carbide layer and the first surface is between 100 angstroms () and 500 angstroms.