Abstract: A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, and the substrate having a fracture toughness of more than or equal to 1.36 MN/m3/2.

Abstract: A group III nitride substrate on which an epitaxially grown layer of good quality can be formed, and a method of manufacturing the same are obtained. A GaN substrate is one of the following: a group III nitride substrate, wherein the number of atoms of an acid material per square centimeter of a surface is not more than 2×1014, and the number of silicon atoms per square centimeter of the surface is not more than 3×1013; a group III nitride substrate, wherein the number of silicon atoms per square centimeter of a surface is not more than 3×1013, and a haze level of the surface is not more than 5 ppm; and a group III nitride substrate, wherein the number of atoms of an acid, material per square centimeter of a surface is not more than 2×1014, and a haze level of the surface is not more than 5 ppm.

Abstract: There is provided a method of producing a nitride-based compound semiconductor device that suppresses the adhesion of foreign matters including impurity, fine particles and the like on a surface of a compound semiconductor. The method of producing a nitride-based compound semiconductor device in accordance with the present invention includes the steps of: preparing a nitride-based compound semiconductor (or a substrate preparation step); and cleaning. In the step of cleaning, the nitride-based compound semiconductor is cleaned with a cleaning liquid having a pH of 7.1 or higher ultrasonically.

Abstract: There is provided a method of producing a thin GaN film-joined substrate, including the steps of: joining on a GaN bulk crystalline body a substrate different in type or chemical composition from GaN; and dividing the GaN bulk crystalline body at a plane having a distance of at least 0.1 ?m and at most 100 ?m from an interface thereof with the substrate different in type, to provide a thin film of GaN on the substrate different in type, wherein the GaN bulk crystalline body had a surface joined to the substrate different in type, that has a maximum surface roughness Rmax of at most 20 ?m. Thus a GaN-based semiconductor device including a thin GaN film-joined substrate including a substrate different in type and a thin film of GaN joined firmly on the substrate different in type, and at least one GaN-based semiconductor layer deposited on the thin film of GaN, can be fabricated at low cost.

Abstract: A group III nitride substrate on which an epitaxially grown layer of good quality can be formed, and a method of manufacturing the same are obtained. A GaN substrate is one of the following: a group III nitride substrate, wherein the number of atoms of an acid material per square centimeter of a surface is not more than 2×1014, and the number of silicon atoms per square centimeter of the surface is not more than 3×1013; a group III nitride substrate, wherein the number of silicon atoms per square centimeter of a surface is not more than 3×1013, and a haze level of the surface is not more than 5 ppm; and a group III nitride substrate, wherein the number of atoms of an acid, material per square centimeter of a surface is not more than 2×1014, and a haze level of the surface is not more than 5 ppm.

Abstract: There is provided a method of producing a thin GaN film-joined substrate, including the steps of: joining on a GaN bulk crystalline body a substrate different in type or chemical composition from GaN; and dividing the GaN bulk crystalline body at a plane having a distance of at least 0.1 ?m and at most 100 ?m from an interface thereof with the substrate different in type, to provide a thin film of GaN on the substrate different in type, wherein the GaN bulk crystalline body had a surface joined to the substrate different in type, that has a maximum surface roughness Rmax of at most 20 ?m. Thus a GaN-based semiconductor device including a thin GaN film-joined substrate including a substrate different in type and a thin film of GaN joined firmly on the substrate different in type, and at least one GaN-based semiconductor layer deposited on the thin film of GaN, can be fabricated at low cost.

Abstract: A method of evaluating damage of a compound semiconductor member, comprising: a step of performing spectroscopic ellipsometry measurement on a surface of the compound semiconductor member; and a step of evaluating damage on the surface of the compound semiconductor member, using a spectrum in a wavelength band containing a wavelength corresponding to a bandgap of the compound semiconductor member, in a spectrum of an optical constant obtained by the spectroscopic ellipsometry measurement.

Abstract: The present method of manufacturing a group III nitride semiconductor layer bonded substrate includes the steps of: implanting ions I of at least any of hydrogen and helium in a region having a prescribed depth D from one main surface of a group III nitride semiconductor substrate; bonding a different-composition substrate with the main surface of the group III nitride semiconductor substrate; obtaining a group III nitride semiconductor layer bonded substrate by separating the group III nitride semiconductor substrate at a region implanted with the ions I; and annealing the group III nitride semiconductor layer bonded substrate at a temperature not lower than 700° C. in an atmosphere of a nitrogen-containing gas N. Thus, a group III nitride semiconductor layer bonded substrate high in crystallinity of a group III nitride semiconductor layer is provided.

Abstract: There is provided a cleaning method and production method that suppresses the adhesion of foreign matters including impurity, fine particles and the like on a surface of a compound semiconductor. A method of cleaning a nitride-based compound semiconductor in accordance with the present invention includes the steps of: preparing a nitride-based compound semiconductor (or a substrate preparation step); and cleaning. In the step of cleaning, a cleaning liquid having a pH of 7.1 or higher is used to clean the nitride-based compound semiconductor.

Abstract: There is provided a cleaning method and production method that suppresses the adhesion of foreign matters including impurity, fine particles and the like on a surface of a compound semiconductor. A method of cleaning a nitride-based compound semiconductor in accordance with the present invention includes the steps of: preparing a nitride-based compound semiconductor (or a substrate preparation step); and cleaning. In the step of cleaning, a cleaning liquid having a pH of 7.1 or higher is used to clean the nitride-based compound semiconductor.

Abstract: Fracture-resistant gallium nitride substrate, and methods of testing for and manufacturing such substrates are made available. A gallium nitride substrate (10) is provided with a front side (12) polished to a mirrorlike finish, a back side (14) on the substrate side that is the opposite of the front side (12). A damaged layer (16) whose thickness d is 30 ?m or less is formed on the back side (14). Given that the strength of the front side (12) is I1 and the strength of the back side (14) is I2, then the ratio I2/I1 is 0.46 or more.

Abstract: Affords III-V nitride semiconductor layer-bonded substrates from which semiconductor device of enhanced properties can be manufactured, and semiconductor devices incorporating the III-V nitride semiconductor layer-bonded substrates. The III-V nitride semiconductor layer-bonded substrate, in which a III-V nitride semiconductor layer and a base substrate are bonded together, is characterized in that thermal expansion coefficient difference between the III-V nitride semiconductor layer and the base substrate is 4.5×10?6 K?1 or less, and in that the thermal conductivity of the base substrate is 50 W·m?1·K?1 or more.

Abstract: Affords a III-V compound semiconductor substrate manufacturing method that enables enhancement of the substrate PL intensity. In such a III-V compound semiconductor substrate manufacturing method, first, the surface 3a of a wafer 3 is polished (polishing step). Second, the surface 3a of the wafer 3 is cleaned (first cleaning step S7). Next, the surface 3a of the wafer 3 is subjected to first dry-etching, employing a halogen-containing gas, while first bias voltage is applied to a chuck 24 for carrying the wafer 3. Subsequently, the surface 3a of the wafer 3 is subjected to second dry-etching, employing the halogen-containing gas (second dry-etching step S11), while second bias power lower than the first bias power is applied to the chuck 24.

Abstract: There is provided a method of producing a thin GaN film-joined substrate, including the steps of: joining on a GaN bulk crystalline body a substrate different in type or chemical composition from GaN; and dividing the GaN bulk crystalline body at a plane having a distance of at least 0.1 ?m and at most 100 ?m from an interface thereof with the substrate different in type, to provide a thin film of GaN on the substrate different in type, wherein the GaN bulk crystalline body had a surface joined to the substrate different in type, that has a maximum surface roughness Rmax of at most 20 ?m. Thus a GaN-based semiconductor device including a thin GaN film-joined substrate including a substrate different in type and a thin film of GaN joined firmly on the substrate different in type, and at least one GaN-based semiconductor layer deposited on the thin film of GaN, can be fabricated at low cost.

Abstract: A method of evaluating damage of a compound semiconductor member, comprising: a step of performing measurement of photoluminescence on a surface of the compound semiconductor member; and a step of evaluating damage on the surface of the compound semiconductor member, using a half width of a peak at a wavelength corresponding to a bandgap of the compound semiconductor member, in an emission spectrum obtained by the measurement of photoluminescence.

Abstract: Fracture-resistant gallium nitride substrate, and methods of testing for and manufacturing such substrates are made available. A gallium nitride substrate (10) is provided with a front side (12) polished to a mirrorlike finish, a back side (14) on the substrate side that is the opposite of the front side (12). A damaged layer (16) whose thickness d is 30 ?m or less is formed on the back side (14). Given that the strength of the front side (12) is I1 and the strength of the back side (14) is I2, then the ratio I2/I1 is 0.46 or more.

Abstract: In a method of working a crystal, when a nitride semiconductor crystal is worked, voltage is applied between the nitride semiconductor crystal and a tool electrode to cause electrical discharge, so that the crystal is partially removed and worked by local heat generated by the electrical discharge.

Abstract: A method of evaluating damage of a compound semiconductor member, comprising: a step of performing spectroscopic ellipsometry measurement on a surface of the compound semiconductor member; and a step of evaluating damage on the surface of the compound semiconductor member, using a spectrum in a wavelength band containing a wavelength corresponding to a bandgap of the compound semiconductor member, in a spectrum of an optical constant obtained by the spectroscopic ellipsometry measurement.

Abstract: A method of evaluating damage of a compound semiconductor member, comprising: a step of performing measurement of photoluminescence on a surface of the compound semiconductor member; and a step of evaluating damage on the surface of the compound semiconductor member, using a half width of a peak at a wavelength corresponding to a bandgap of the compound semiconductor member, in an emission spectrum obtained by the measurement of photoluminescence.

Abstract: There is provided a cleaning method and production method that suppresses the adhesion of foreign matters including impurity, fine particles and the like on a surface of a compound semiconductor. A method of cleaning a nitride-based compound semiconductor in accordance with the present invention includes the steps of: preparing a nitride-based compound semiconductor (or a substrate preparation step); and cleaning. In the step of cleaning, a cleaning liquid having a pH of 7.1 or higher is used to clean the nitride-based compound semiconductor.