Abstract: A semiconductor device includes a substrate, a buffer layer on the substrate, and a plurality of nitride semiconductor layers on the buffer layer. The semiconductor device further includes at least one masking layer and at least one inter layer between the plurality of nitride semiconductor layers. The at least one inter layer is on the at least one masking layer.

Abstract: A curvature-control-material (CCM) is formed on one side of a substrate prior to forming a Group III nitride material on the other side of the substrate. The CCM possess a thermal expansion coefficient (TEC) that is lower than the TEC of the substrate and is stable at elevated growth temperatures required for formation of a Group III nitride material. In some embodiments, the deposition conditions of the CCM enable a flat-wafer condition for the Group III nitride material maximizing the emission wavelength uniformity of the Group III nitride material. Employment of the CCM also reduces the final structure bowing during cool down leading to reduced convex substrate curvatures. In some embodiments, the final structure curvature can further be engineered to be concave by proper selection of CCM properties, and via controlled selective etching of the CCM, this method enables the final structure to be flat.

Abstract: A structure and method of producing a semiconductor structure including a semi-insulating semiconductor layer, a plurality of isolated devices formed over the semi-insulating semiconductor layer, and a metal-semiconductor alloy region formed in the semi-insulating semiconductor layer, where the metal-semiconductor alloy region electrically connects two or more of the isolated devices.

Abstract: A method to remove epitaxial semiconductor layers from a substrate by growing an epitaxial sacrificial layer on the substrate where the sacrificial layer is a transition metal nitride (TMN) or a TMN ternary compound, growing one or more epitaxial device layers on the sacrificial layer, and separating the device layers from the substrate by etching the sacrificial layer to completely remove the sacrificial layer without damaging or consuming the substrate or any device layer. Also disclosed are the related semiconductor materials made by this method.

Abstract: Si(1-v-w-x)CwAlxNv crystals in a mixed crystal state are formed. A method for manufacturing an easily processable Si(1-v-w-x)CwAlxNv substrate, a method for manufacturing an epitaxial wafer, a Si(1-v-w-x)CwAlxNv substrate, and an epitaxial wafer are provided. A method for manufacturing a Si(1-v-w-x)CwAlxNv substrate 10a includes the following steps. First, a Si substrate 11 is prepared. A Si(1-v-w-x)CwAlxNv layer 12 (0<v<1, 0?w<1, 0<x<1, and 0<v+w+x<1) is then grown on the Si substrate 11 by a pulsed laser deposition method.

Abstract: Passivation of group III-nitride heterojunction devices is described herein. The passivation facilitates simultaneous realization of effective/high current collapse suppression and low leakage current without the use of a sophisticated multiple-field plate technique. The passivation can be achieved by growing a charge-polarized AlN thin film on the surface of a group III-nitride based heterojunction device by plasma-enhanced atomic layer deposition such that positive polarization charges are induced at the interface to compensate for a majority of negative charges at the interface.

Abstract: The present invention discloses an electronic device using a group III nitride substrate fabricated via the ammonothermal method. By utilizing the high-electron concentration of ammonothermally grown substrates having the dislocation density less than 105 cm?2, combined with a high-purity active layer of Ga1-x-yAlxInyN (0?x?1, 0?y?1) grown by a vapor phase method, the device can attain high level of breakdown voltage as well as low on-resistance. To realize a good matching between the ammonothermally grown substrate and the high-purity active layer, a transition layer is optionally introduced. The active layer is thicker than a depletion region created by a device structure in the active layer.

Abstract: The present invention discloses an electronic device using a group III nitride substrate fabricated via the ammonothermal method. By utilizing the high-electron concentration of ammonothermally grown substrates having the dislocation density less than 105 cm?2, combined with a high-purity active layer of Ga1-x-yAlxInyN (0?x?1, 0?y?1) grown by a vapor phase method, the device can attain high level of breakdown voltage as well as low on-resistance. To realize a good matching between the ammonothermally grown substrate and the high-purity active layer, a transition layer is optionally introduced. The active layer is thicker than a depletion region created by a device structure in the active layer.

Abstract: An AlGaN/GaN.HEMT includes, a compound semiconductor lamination structure; a p-type semiconductor layer formed on the compound semiconductor lamination structure; and a gate electrode formed on the p-type semiconductor layer, in which Mg being an inert element of p-GaN is introduced into both sides of the gate electrode at the p-type semiconductor layer, and introduced portions of Mg are inactivated.

Abstract: Oxygen can be doped into a gallium nitride crystal by preparing a non-C-plane gallium nitride seed crystal, supplying material gases including gallium, nitrogen and oxygen to the non-C-plane gallium nitride seed crystal, growing a non-C-plane gallium nitride crystal on the non-C-plane gallium nitride seed crystal and allowing oxygen to infiltrating via a non-C-plane surface to the growing gallium nitride crystal. Oxygen-doped {20-21}, {1-101}, {1-100}, {11-20} or {20-22} surface n-type gallium nitride crystals are obtained.

Abstract: A light-receiving element includes a III-V group compound semiconductor substrate, a light-receiving layer having a type II multi-quantum well structure disposed on the substrate, and a type I wavelength region reduction means for reducing light in a wavelength region of type I absorption in the type II multi-quantum well structure disposed on a light incident surface or between the light incident surface and the light-receiving layer.

Abstract: A method of forming a semiconductive substrate material for an electronic device including forming a plurality of semiconductive layers on a substrate during a continuous growth process in a reaction chamber, wherein during the continuous growth process, a release layer is formed between a base layer and an epitaxial layer by altering at least one growth process parameter during the continuous growth process. The method also including separating the plurality of semiconductive layers from the substrate.

Abstract: An aluminum nitride single crystal in the form of polygonal columns, the polygonal columns having the following properties [a] to [c]: [a] the content of a metal impurity is below a detection limit, [b] the average bottom area is from 5×103 to 2×105 ?m2, and [c] the average height is 50 ?m to 5 mm. The above aluminum nitride single crystal is preferably obtainable in a method including the steps of sublimating an aluminum nitride starting material (A) containing 0.1 to 30% by mass of a rare earth oxide by heating the starting material at a temperature of not lower than 2000° C., depositing aluminum nitride on a hexagonal single crystal substrate and thereby growing aluminum nitride single crystal in the shape of polygonal columns.

Abstract: Semiconductor devices useful as light emitting diodes or power transistors are provided. The devices produced by depositing a Zn—O-based layer comprising nanostructures on a Si-based substrate, with or without a metal catalyst layer deposited therebetween. Futhermore, a pair of adjacent p-n junction forming layers is deposited on the ZnO-based layer, where one of the pair is an n-type epitaxial layer, and the other is a p-type epitaxial layer. One or more epxitaxial layers may, optionally, be deposited between the ZnO-based layer and the pair of adjacent p-n junction forming layers.

Abstract: A substrate including a body comprising a Group III-V material and having an upper surface, the body comprising an offcut angle defined between the upper surface and a crystallographic reference plane, and the body further having an offcut angle variation of not greater than about 0.6 degrees.

Abstract: The present disclosure relates generally to semiconductor techniques. More specifically, embodiments of the present disclosure provide methods for efficiently dicing substrates containing gallium and nitrogen material. Additionally, the present disclosure provides techniques resulting in an optical device comprising a substrate having a dislocation bundle center being used as a conductive region for a contact.

Abstract: The present invention relates to a method for relaxing a strained material layer by providing a strained material layer and a low-viscosity layer formed on a first face of the strained material layer; forming a stiffening layer on at least one part of a second face of the strained material layer opposite to the first face thereby forming a multilayer stack; and subjecting the multilayer stack to a heat treatment thereby at least partially relaxing the strained material layer.

Abstract: Provided are methods for making a device or device component by providing a multi layer structure having a plurality of functional layers and a plurality of release layers and releasing the functional layers from the multilayer structure by separating one or more of the release layers to generate a plurality of transferable structures. The transferable structures are printed onto a device substrate or device component supported by a device substrate. The methods and systems provide means for making high-quality and low-cost photovoltaic devices, transferable semiconductor structures, (opto-)electronic devices and device components.

Abstract: A III-N semiconductor channel is compositionally graded between a transition layer and a III-N polarization layer. In embodiments, a gate stack is deposited over sidewalls of a fin including the graded III-N semiconductor channel allowing for formation of a transport channel in the III-N semiconductor channel adjacent to at least both sidewall surfaces in response to a gate bias voltage. In embodiments, a gate stack is deposited completely around a nanowire including a III-N semiconductor channel compositionally graded to enable formation of a transport channel in the III-N semiconductor channel adjacent to both the polarization layer and the transition layer in response to a gate bias voltage.

Abstract: A III nitride structure includes a film 108 having a surface composed of a metal formed in a predetermined region on the surface of a substrate 102, and a fine columnar crystal 110 composed of at least a III nitride semiconductor formed on the surface of the substrate 102, wherein the spatial occupancy ratio of the fine columnar crystal 110 is higher on the surface of the substrate 102 where the film 108 is not formed than that on the film.

Abstract: A method for producing a semiconductor laser having an edge window structure includes the steps of forming masks of insulating films on a nitride-based III-V compound semiconductor substrate including first regions and second regions periodically arranged in parallel therebetween; and growing a nitride-based III-V compound semiconductor layer in a region not covered by the masks. The first region between each two adjacent second regions has two or more positions, symmetrical with respect to a center line thereof, where laser stripes are to be formed. The masks are formed on one or both sides of each of the positions where the laser stripes are to be formed at least near a position where edge window structures are to be formed such that the masks are symmetrical with respect to the center line. The nitride-based III-V compound semiconductor layer includes an active layer containing at least indium and gallium.

Abstract: The disclosure relates to a method for manufacturing a III-V device and the III-V device obtained therefrom. The method comprises providing a semiconductor substrate including at least a recess area and forming a buffer layer overlying the semiconductor substrate in the recess area. The buffer layer includes a binary III-V compound formed at a first growth temperature by selective epitaxial growth from a group III precursor and a group V precursor in the presence of a carrier gas. The first growth temperature is equal or slightly higher than a cracking temperature of each of the group III precursor and of the group V precursor.

Abstract: A nitride semiconductor substrate suitable for a high withstand voltage power device is provided in which current collapse is controlled, while reducing leakage current. In a nitride semiconductor substrate, wherein a buffer layer, an active layer, and an electron supply layer, each comprising a group 13 nitride, are stacked one by one on a silicon single crystal substrate, the buffer layer has a structure where a multilayer stack in which a pair of nitride layers having different concentrations of Al or Ga are repeatedly deposited a plurality of times on an initial layer of AlxGa1-xN (0?x?1) is stacked, and includes a doping layer whose carbon concentration is 1×1018 to 1×1021 cm?3 and whose Si concentration is 1×1017 to 1×1020 cm?3, a thickness of the doping layer is 15% or more of the total thickness of the buffer layer.

Abstract: According to example embodiments, a normally-off high electron mobility transistor (HEMT) includes: a channel layer having a first nitride semiconductor, a channel supply layer on the channel layer, a source electrode and a drain electrode at sides of the channel supply layer, a depletion-forming layer on the channel supply layer, a gate insulating layer on the depletion-forming layer, and a gate electrode on the gate insulation layer. The channel supply layer includes a second nitride semiconductor and is configured to induce a two-dimensional electron gas (2DEG) in the channel layer. The depletion-forming layer is configured has at least two thicknesses and is configured to form a depletion region in at least a partial region of the 2DEG. The gate electrode contacts the depletion-forming layer.

Abstract: Electronic device quality Aluminum Antimonide (AlSb)-based single crystals produced by controlled atmospheric annealing are utilized in various configurations for solar cell applications. Like that of a GaAs-based solar cell devices, the AlSb-based solar cell devices as disclosed herein provides direct conversion of solar energy to electrical power.

Abstract: A rare earth oxide gate dielectric on III-N material grown on a silicon substrate includes a single crystal stress compensating template positioned on a silicon substrate. The stress compensating template is substantially crystal lattice matched to the surface of the silicon substrate. A GaN structure is positioned on the surface of the stress compensating template and substantially crystal lattice matched thereto. An active layer of single crystal III-N material is grown on the GaN structure and substantially crystal lattice matched thereto. A single crystal rare earth oxide dielectric layer is grown on the active layer of III-N material.

Abstract: A method of fabricating a composite semiconductor structure is provided. Pedestals are formed in a recess of a first substrate. A second substrate is then placed within the recess in contact with the pedestals. The pedestals have a predetermined height so that a device layer within the second substrate aligns with a waveguide of the first substrate, where the waveguide extends from an inner wall of the recess.

Abstract: Group-III nitride crystal composites made up of especially processed crystal slices, cut from III-nitride bulk crystal, whose major surfaces are of {1-10±2}, {11-2±2}, {20-2±1} or {22-4±1} orientation, disposed adjoining each other sideways with the major-surface side of each slice facing up, and III-nitride crystal epitaxially present on the major surfaces of the adjoining slices, with the III-nitride crystal containing, as principal impurities, either silicon atoms or oxygen atoms.

Abstract: III-N material grown on a silicon substrate includes a single crystal rare earth oxide layer positioned on a silicon substrate. The rare earth oxide is substantially crystal lattice matched to the surface of the silicon substrate. A first layer of III-N material is positioned on the surface of the rare earth oxide layer. An inter-layer of aluminum nitride (AlN) is positioned on the surface of the first layer of III-N material and an additional layer of III-N material is positioned on the surface of the inter-layer of aluminum nitride. The inter-layer of aluminum nitride and the additional layer of III-N material are repeated n-times to reduce or engineer strain in a final III-N layer. A cap layer of AlN is grown on the final III-N layer and a III-N layer of material with one of an LED structure and an HEMT structure is grown on the AlN cap layer.

Abstract: A semiconductor structure includes a barrier layer, a spacer structure, and a channel layer. The barrier layer includes a group III nitride. The spacer structure includes first and second aluminum nitride layers and an intermediate layer. The intermediate layer includes a group III nitride and is between the first and second aluminum nitride layers. The intermediate layer has a first free charge carrier density at an interface with the second aluminum nitride layer. The spacer structure is between the barrier layer and the channel layer. The channel layer includes a group III nitride and has a second free charge carrier density at an interface with the first aluminum nitride layer of the spacer structure. The first aluminum nitride layer, the intermediate layer, and the second aluminum nitride layer have layer thicknesses so the first free charge carrier density is less than 10% of the second free charge carrier density.

Abstract: Methods of fabricating semiconductor devices or structures include forming structures of a semiconductor material overlying a layer of a compliant material, subsequently changing the viscosity of the compliant material to relax the semiconductor material structures, and utilizing the relaxed semiconductor material structures as a seed layer in forming a continuous layer of relaxed semiconductor material. In some embodiments, the layer of semiconductor material may comprise a III-V type semiconductor material, such as, for example, indium gallium nitride. Novel intermediate structures are formed during such methods. Engineered substrates include a continuous layer of semiconductor material having a relaxed lattice structure.

Abstract: Described is a method for producing a semiconductor device (100), in which at least one column-shaped or wall-shaped semiconductor device (10, 20) extending in a main direction (z) is formed on a substrate (30), wherein at least two sections (11, 13, 21, 23) of a first crystal type and one section (12, 22) of a second crystal type therebetween are formed in an active region (40), each section with a respective predetermined height (h1, h2), wherein the first and second crystal types have different lattice constants and each of the sections of the first crystal type has a lattice strain which depends on the lattice constants in the section of the second crystal type.

Abstract: A nitride semiconductor device includes: first electrode interconnect layers extending in parallel with one another over the nitride semiconductor layer and divided by areas extending across a longitudinal direction of the first electrode interconnect layers; first gate electrodes extending along the first electrode interconnect layers; first gate electrode connecting interconnects extending in associated ones of the areas dividing the first electrode interconnect layers and being in connection to the first gate electrodes; first electrode connecting interconnects formed above the first gate electrode connecting interconnects and being in connection to the first electrode interconnect layers; a first electrode upper interconnects formed on the first electrode connecting interconnects with an interconnect insulating film interposed therebetween, and being in connection to the first electrode connecting interconnects through associated ones of openings of the interconnect insulating film.

Abstract: Methods of fabricating semiconductor devices or structures include bonding a layer of semiconductor material to another material at a temperature, and subsequently changing the temperature of the layer of semiconductor material. The another material may be selected to exhibit a coefficient of thermal expansion such that, as the temperature of the layer of semiconductor material is changed, a controlled and/or selected lattice parameter is imparted to or retained in the layer of semiconductor material. In some embodiments, the layer of semiconductor material may comprise a III-V type semiconductor material, such as, for example, indium gallium nitride. Novel intermediate structures are formed during such methods. Engineered substrates include a layer of semiconductor material having an average lattice parameter at room temperature proximate an average lattice parameter of the layer of semiconductor material previously attained at an elevated temperature.

Abstract: The present invention provides a method of manufacturing a semiconductor substrate that includes a substrate, a first semiconductor layer arranged on the substrate, a metallic material layer arranged on the first semiconductor layer, a second semiconductor layer arranged on the first semiconductor layer and the metallic material layer, and a cavity formed in the first semiconductor layer under the metallic material layer.

Abstract: A substrate structure includes a substrate, a nucleation layer on the substrate and including a group III-V compound semiconductor material having a lattice constant that is different from that of the substrate by less than 1%, and a buffer layer on the nucleation layer and including first and second layers, wherein the first and second layers include group III-V compound semiconductor materials having lattice constants that are greater than that of the nucleation layer by 4% or more.

Abstract: A semiconductor light emitting device includes a structural body, a first electrode layer, an intermediate layer and a second electrode layer. The structural body includes a first semiconductor layer of first conductivity type, a second semiconductor layer of second conductivity type, and a light emitting layer between the first and second semiconductor layers. The first electrode layer is on a side of the second semiconductor layer opposite to the first semiconductor layer; the first electrode layer includes a metal portion and plural opening portions piercing the metal portion along a direction from the first semiconductor layer toward the second semiconductor layer, having an equivalent circular diameter not less than 10 nanometers and not more than 5 micrometers. The intermediate layer is between the first and second semiconductor layers in ohmic contact with the second semiconductor layer. The second electrode layer is electrically connected to the first semiconductor layer.

Abstract: A semiconductor structure, comprising: a substrate; a seed layer over an upper surface of the substrate; a semiconductor layer disposed over the seed layer; a transistor device in the semiconductor layer; wherein the substrate has an aperture therein, such aperture extending from a bottom surface of the substrate and terminating on a bottom surface of the seed layer; and an opto-electric structure disposed on the bottom surface of the seed layer.

Abstract: An epitaxial substrate, in which a group of group-III nitride layers is formed on a single-crystal silicon substrate so that a crystal plane is approximately parallel to a substrate surface, comprises: a first group-III nitride layer formed of AlN on the base substrate; a second group-III nitride layer formed of InxxAlyyGazzN (xx+yy+zz=1, 0?xx?1, 0<yy?1 and 0<zz?1) on the first group-III nitride layer; and at least one third group-III nitride layer epitaxially-formed on the second group-III nitride layer, wherein: the first group-III nitride layer is a layer containing multiple defects including at least one type of a columnar crystal, a granular crystal, a columnar domain and a granular domain; and an interface between the first group-III nitride layer and the second group-III nitride layer is a three-dimensional asperity surface.

Abstract: A method of fabricating a substrate for a semipolar III-nitride device, comprising patterning and forming one or more mesas on a surface of a semipolar III-nitride substrate or epilayer, thereby forming a patterned surface of the semipolar III-nitride substrate or epilayer including each of the mesas with a dimension l along a direction of a threading dislocation glide, wherein the threading dislocation glide results from a III-nitride layer deposited heteroepitaxially and coherently on a non-patterned surface of the substrate or epilayer.

Abstract: Provided is a crack-free epitaxial substrate having a small amount of dislocations in which a silicon substrate is used as a base substrate. An epitaxial substrate includes a substrate made of (111) single crystal silicon and a base layer group in which a plurality of base layers are laminated. Each of the plurality of base layers includes a first group-III nitride layer made of AlN and a second group-III nitride layer made of AlyyGazzN formed on the first group-III nitride layer. The first group-III nitride layer has many crystal defects. An interface between the first and second group-III nitride layers is a three-dimensional concavo-convex surface. In the base layer other than the base layer formed immediately above the base substrate, the first group-III nitride layer has a thickness of 50 nm or more and 100 nm or less and the second group-III nitride layer satisfies 0?yy?0.2.

Abstract: The present invention relates to a method for manufacturing semiconductor materials comprising epitaxial growing of group III-V materials, for example gallium arsenide (GaAs), on for example a non III-V group material like silicon (Si) substrates (wafers), and especially to pre-processing steps providing a location stabilisation of dislocation faults in a surface layer of the non III-V material wafer in an orientation relative to an epitaxial material growing direction during growing of the III-V materials, wherein the location stabilised dislocation fault orientations provides a barrier against threading dislocations (stacking of faults) from being formed in the growing direction of the III-V materials during the epitaxial growth process.

Abstract: A group III nitride crystal substrate is provided in which a uniform distortion at a surface layer of the crystal substrate represented by a value of |d1?d2|/d2 obtained from a plane spacing d1 at the X-ray penetration depth of 0.3 ?m and a plane spacing d2 at the X-ray penetration depth of 5 ?m is equal to or lower than 1.9×10?3, and the main surface has a plane orientation inclined in the <10-10> direction at an angle equal to or greater than 10° and equal to or smaller than 80° with respect to one of (0001) and (000-1) planes of the crystal substrate. A group III nitride crystal substrate suitable for manufacturing a light emitting device with a blue shift of an emission suppressed, an epilayer-containing group III nitride crystal substrate, a semiconductor device and a method of manufacturing the same can thereby be provided.

Abstract: Provided are a nitride thin film structure and a method of forming the same. If a nitride thin film is formed on a substrate that is not a nitride, many defects are generated by a difference in lattice constants between the substrate and the nitride thin film. Also, there is a problem of warping the substrate by a difference in thermal expansion coefficients between the substrate and the nitride thin film. In order to solve the problems, the present invention suggests a thin film structure in which after coating hollow particles, i.e. hollow structures on the substrate, the nitride thin film is grown thereon and the method of forming the thin film structure. According to the present invention, since an epitaxial lateral overgrowth (ELO) effect can be obtained by the hollow structures, high-quality nitride thin film can be formed.

Abstract: A method for producing a Group III nitride crystal includes the steps of cutting a plurality of Group III nitride crystal substrates 10p and 10q having a major surface from a Group III nitride bulk crystal 1, the major surfaces 10pm and 10qm having a plane orientation with an off-angle of five degrees or less with respect to a crystal-geometrically equivalent plane orientation selected from the group consisting of {20?21}, {20?2?1}, {22?41}, and {22?4?1}, transversely arranging the substrates 10p and 10q adjacent to each other such that the major surfaces 10pm and 10qm of the substrates 10p and 10q are parallel to each other and each [0001] direction of the substrates 10p and 10q coincides with each other, and growing a Group III nitride crystal 20 on the major surfaces 10pm and 10qm of the substrates 10p and 10q.

Abstract: A method of fabricating a semiconductor device can include forming a III-N semiconductor layer in a reactor and injecting a hydrocarbon precursor into the reactor, thereby carbon doping the III-N semiconductor layer and causing the III-N semiconductor layer to be insulating or semi-insulating. A semiconductor device can include a substrate and a carbon doped insulating or semi-insulating III-N semiconductor layer on the substrate. The carbon doping density in the III-N semiconductor layer is greater than 5×1018 cm?3 and the dislocation density in the III-N semiconductor layer is less than 2×109 cm?2.

Abstract: A gallium nitride rectifying device includes a p-type gallium nitride based semiconductor layer and an n-type gallium nitride based semiconductor layer, the two layers forming a pn junction with each other. The p-type gallium nitride based semiconductor layer has a carrier trap (level) density of not more than 1×1018 cm?3, or the n-type gallium nitride based semiconductor layer has a carrier trap (level) density of not more than 1×1016 cm?3.

Abstract: Methods of fabricating semiconductor devices or structures include forming structures of a semiconductor material overlying a layer of a compliant material, subsequently changing the viscosity of the compliant material to relax the semiconductor material structures, and utilizing the relaxed semiconductor material structures as a seed layer in forming a continuous layer of relaxed semiconductor material. In some embodiments, the layer of semiconductor material may comprise a III-V type semiconductor material, such as, for example, indium gallium nitride. Novel intermediate structures are formed during such methods. Engineered substrates include a continuous layer of semiconductor material having a relaxed lattice structure.

Abstract: In an exemplary implementation, a method includes growing a III-Nitride body over a group IV substrate in a semiconductor wafer. The method includes forming at least one device layer over the III-Nitride body. The method also includes etching grid array trenches in the III-Nitride body, where the etching of the grid array trenches may extend into the group IV substrate. The method can also include forming an edge trench around a perimeter of the semiconductor wafer. The method further includes forming separate dies by cutting the semiconductor wafer approximately along the grid array trenches.

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 loge n and less than a value represented by loge ?=18.5?0.288 loge n, 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.