Abstract: A nitride-based semiconductor substrate has a substrate formed of a nitride-based semiconductor crystal having a mixed crystal composition with three elements or more. The substrate has a diameter of not less than 25 mm, and a thermal resistivity in a range of 0.02 Kcm2/W to 0.5 Kcm2/W in its thickness direction.

Abstract: A nitride-based semiconductor substrate having a diameter of 25 mm or more, a thickness of 250 micrometers or more, and an optical absorption coefficient of less than 7 cm?1 to light with a wavelength of 380 nm or more. The nitride-based semiconductor substrate is made by the HVPE method that uses gallium chloride obtained by reacting a Ga melt with a hydrogen chloride gas. The Ga melt is contacted with the hydrogen chloride gas for one minute or more to produce the gallium chloride.

Abstract: A chamfering part is partially formed on the backside, opposite to the front side of a substrate on which epitaxial growth is performed. When a size of the substrate is set at x (mm), preferably length of the chamfering part applied to the backside of the substrate is set at 2 mm or more and 0.15x (mm) or less. In addition, when the substrate is placed on a flat surface, with the front side turned up, preferably height and depth of a gap formed between the substrate and the flat surface are set at 0.2 mm or more.

Abstract: The present invention generally relates to methods, systems and computer readable media for the diagnosis and/or prognosis of a cardiac stress and/or skeletal muscle stress in a subject. In particular, in one embodiment, the methods, systems and computer readable media detect a level of Fstl expression, such as Fstl1 polypeptide or mRNA expression in a biological sample obtained from a subject, where a high level relative to a reference Fstl expression level is indicative of a subject having, or is at risk of cardiac stress and/or skeletal muscle stress. In such embodiments, the method futher comprises administering or undertaking an appropriate therapy in a subject identified to have or be at risk of cardiac stress and/or skeletal muscle stress.

Abstract: A nitride-based compound semiconductor substrate mainly used for an epitaxial growth of a nitride semiconductor and a method for fabricating the same are disclosed. The nitride-based compound semiconductor substrate has a composition of AlxGa1-xN (0<x<1), a principal plane of C face, an area of 2 cm2 or more, and a thickness of 200 ?m or more. The substrate having this structure is fabricated by a HVPE (hydride vapor phase epitaxy) method by using an organic Al compound such as TMA (trimethyl aluminum) or TEA (trimethyl aluminum) as an Al source, A stable crystal growth can be obtained without damaging a reacting furnace, and a large-sized AlGaN crystal substrate with an excellent crystallinity can be obtained.

Abstract: A GaN single-crystal substrate has a substrate surface in which polarity inversion zones are included. The number density of the polarity inversion zones in the substrate surface is not more than 20 cm?2. A GaN single crystal production method includes introducing group III and V raw material gases on a substrate, and growing a GaN single crystal on the substrate. The growth temperature is within the range of not less than 1100° C. and not more than 1400° C., the group V to III raw material gas partial pressure ratio (V/III ratio) is within the range of not less than 0.4 and not more than 1, and the number density of polarity inversion zones in a surface of the substrate is not more than 20 cm?2.

Abstract: A nitride-based semiconductor substrate has a diameter of 25 mm or more, a thickness of 250 micrometers or more, a n-type carrier concentration of 1.2×1018 cm?3 or more and 3×1019 cm?3 or less, and a thermal conductivity of 1.2 W/cmK or more and 3.5 W/cmK or less. Alternatively, the substrate has an electron mobility ? [cm2/Vs] of more than a value represented by loge?=17.7?0.288 logen and less than a value represented by loge?=18.5?0.288 logen, where the substrate has a n-type carrier concentration n [cm?3] that is 1.2×1018 cm?3 or more and 3×1019 cm?3 or less.

Abstract: A Group III nitride semiconductor substrate is formed of a Group III nitride single crystal, and has a diameter of not less than 25.4 mm and a thickness of not less than 150 ?m. The substrate satisfies that a ratio of ??/? is not more than 0.1, where ? is a thermal expansion coefficient calculated from a temperature change in outside dimension of the substrate, and ?? is a difference (???L) between the thermal expansion coefficient ? and a thermal expansion coefficient ?L calculated from a temperature change in lattice constant of the substrate.

Abstract: A nitride semiconductor ingot is formed of a nitride semiconductor, and has a length of more than 20 mm and a diameter of not less than 50.8 mm. The nitride semiconductor ingot includes no cracks in a portion except 3 mm from an outermost thereof.

Abstract: A method of making a nitride-based compound semiconductor crystal has the step of growing a nitride-based compound semiconductor crystal with a predetermined thickness by using a nitride-based compound semiconductor substrate as a seed crystal. The nitride-based compound semiconductor substrate as the seed crystal is polished at both surfaces thereof.

Abstract: A nitride-based semiconductor substrate has a substrate formed of a nitride-based semiconductor crystal having a mixed crystal composition with three elements or more. The substrate has a diameter of not less than 25 mm, and a thermal resistivity in a range of 0.02 Kcm2/W to 0.5 Kcm2/W in its thickness direction.

Abstract: A group III-V nitride-based semiconductor substrate having a group III-V nitride-based semiconductor thick film with a same composition in the entire film. The thick film has a first region with a predetermined impurity concentration and a second region with an impurity concentration lower than the first region.

Abstract: A nitride-based semiconductor substrate has a diameter of 25 mm or more, a thickness of 250 micrometers or more, a n-type carrier concentration of 1.2×1018 cm?3 or more and 3×1019 cm?3 or less, and a thermal conductivity of 1.2 W/cmK or more and 3.5 W/cmK or less. Alternatively, the substrate has an electron mobility ? [cm2/Vs] of more than a value represented by loge ?=17.7-0.288 logen and less than a value represented by loge ?=18.5-0.288 logen, where the substrate has a n-type carrier concentration n [cm?3] that is 1.2×1018 cm?3 or more and 3×1019 cm?3 or less.

Abstract: A nitride-based semiconductor substrate having a diameter of 25 mm or more, a thickness of 250 micrometers or more, and an optical absorption coefficient of less than 7 cm?1 to light with a wavelength of 380 nm or more. The nitride-based semiconductor substrate is made by the HVPE method that uses gallium chloride obtained by reacting a Ga melt with a hydrogen chloride gas. The Ga melt is contacted with the hydrogen chloride gas for one minute or more to produce the gallium chloride.

Abstract: A metal layer is formed directly on a nitride-based compound semiconductor base layer over a substrate body. The metal layer includes at least one metal exhibiting an atomic interaction, with assistance of a heat treatment, to atoms constituting the base layer to promote removal of constitutional atoms from the base layer, whereby pores penetrating the metal layer are formed, while many voids are formed in the nitride-based compound semiconductor base layer. An epitaxial growth of a nitride-based compound semiconductor crystal is made with an initial transient epitaxial growth, which fills the voids, and a subsequent main epitaxial growth over the porous metal layer.

Abstract: The present invention provides a group III nitride semiconductor substrate with low defect density as well as small warp and a process for producing the same; for instance, the process according to the present invention comprises the following series of steps of: forming a metallic Ti film 63 on a sapphire substrate 61, followed by treatment of nitration to convert it into a TiN film 64 having fine pores; thereafter growing a HVPE-GaN layer 66 thereon; forming voids 65 in the HVPE-GaN layer 66 by means of effects of the metallic Ti film 63 and the TiN film 64; and peeling the sapphire substrate 61 from the region of the voids 65 to remove it therefrom.

Abstract: A group III-V nitride-based semiconductor substrate having a group III-V nitride-based semiconductor thick film with a same composition in the entire film. The thick film has a first region with a predetermined impurity concentration and a second region with an impurity concentration lower than the first region.

Abstract: A method of making a group III-V nitride-based semiconductor substrate has the steps of: providing a first crystal substrate; placing the first crystal substrate on a susceptor; holding down the first crystal substrate on the susceptor; and growing a first group III-V nitride-based semiconductor crystal on the first crystal substrate.

Abstract: A method of making a group III-V nitride-based semiconductor crystal has: a first step of providing a first semiconductor crystal substrate; a second step of growing a first group III-V nitride-based semiconductor crystal on the first semiconductor crystal substrate in a first crystal axis direction until when reaching a first thickness; a third step of cutting the first group III-V nitride-based semiconductor crystal along a cutting plane parallel to a propagation direction with a highest threading dislocation density existing inside of the first group III-V nitride-based semiconductor crystal; and a fourth step of growing a second group III-V nitride-based semiconductor crystal on the cutting plane of the first group III-V nitride-based semiconductor crystal until when reaching a second thickness. The second group III-V nitride-based semiconductor crystal is provided as the group III-V nitride-based semiconductor crystal.

Abstract: A method of making a nitride-based compound semiconductor crystal has the step of growing a nitride-based compound semiconductor crystal with a predetermined thickness by using a nitride-based compound semiconductor substrate as a seed crystal. The nitride-based compound semiconductor substrate as the seed crystal is polished at both surfaces thereof.