Abstract: Provided is a crack-free epitaxial substrate with reduced warping, in which a silicon substrate is used as a base substrate. The epitaxial substrate includes a (111) single crystal Si substrate, a superlattice layer group in which a plurality of superlattice layers are laminated, and a crystal layer. The superlattice layer is formed of a first unit layer and a second unit layer made of group-III nitrides having different compositions being alternately and repeatedly laminated. The crystal layer is made of a group-III nitride and formed above the base substrate so as to be positioned at an upper side of the superlattice layer group relative to the base substrate. The superlattice layer group has a compressive strain contained therein. In the superlattice layer group, the more distant the superlattice layer is from the base substrate, the greater the compressive strain becomes.

Abstract: Provided are a group 13 nitride composite substrate allowing for the production of a semiconductor device suitable for high-frequency applications while including a conductive GaN substrate, and a semiconductor device produced using this substrate. The group 13 nitride composite substrate includes a base material of an n-conductivity type formed of GaN, a base layer located on the base material, being a group 13 nitride layer having a resistivity of 1×106 ?·cm or more, a channel layer located on the base layer, being a GaN layer having a total impurity density of 1×1017/cm3 or less, and a barrier layer that is located on the channel layer and is formed of a group 13 nitride having a composition AlxInyGa1-x-yN (0?x?1, 0?y?1).

Abstract: Provided is an epitaxial substrate for use in a semiconductor element, having excellent characteristics and capable of suitably suppressing diffusion of elements from a cap layer. An epitaxial substrate for use in a semiconductor element, in which a group of group-III nitride layers are laminated on a base substrate such that a (0001) crystal plane of the group of group-III nitride layers is substantially in parallel with a substrate surface of the base substrate, includes: a channel layer made of a first group-III nitride having a composition of Inx1Aly1Gaz1N (x1+y1+z1=1, z1>0); a barrier layer made of a second group-III nitride having a composition of Inx2Aly2N (x2+y2=1, x2>0, y2>0); an anti-diffusion layer made of AlN and having a thickness of 3 nm or more; and a cap layer made of a third group-III nitride having a composition of Inx3Aly3Gaz3N (x3+y3+z3=1, z3>0).

Abstract: Provided is a crack-free epitaxial substrate having a small amount of warping, in which a silicon substrate is used as a base substrate. The epitaxial substrate includes: a (111) single crystal Si substrate and a buffer layer formed of a plurality of lamination units being continuously laminated. The lamination unit includes: a composition modulation layer formed of a first and a second unit layer having different compositions being alternately and repeatedly laminated such that a compressive strain exists therein; a termination layer formed on an uppermost portion of the composition modulation layer, the termination layer acting to maintain the compressive strain existing in the composition modulation layer; and a strain reinforcing layer formed on the termination layer, the strain reinforcing layer acting to enhance the compressive strain existing in the composition modulation layer.

Abstract: There is provided a structure of a combustion chamber for an engine which enhances a thermal efficiency of the engine to enhance a fuel efficiency, and an inner wall structure of a flow path through which an intake gas or an exhaust gas of the engine flows. The structure of the combustion chamber for the engine includes a heat-insulating member 1 including a heat-insulating layer 3 formed on the surface of an engine constituting member 21 constituting the combustion chamber for the engine and a dense surface layer 2 formed on the surface of the heat-insulating layer 3. Furthermore, the heat-insulating layer 3 includes ceramic and/or glass, and has pores of pore diameters of 10 to 500 nm and a porosity of 10 to 99%, and the dense surface layer 2 includes ceramic and/or glass and has a porosity of 5% or less.

Abstract: Provided is a crack-free epitaxial substrate having excellent breakdown voltage properties in which a silicon substrate is used as a base. The epitaxial substrate includes a (111) single crystal Si substrate and a buffer layer including a plurality of first lamination units. Each of those units includes a composition modulation layer formed of a first composition layer made of AlN and a second composition layer made of AlxGa1-xN being alternately laminated, and a first intermediate layer made of AlyGa1-yN (0?y<1). The relationship of x(1)?x(2)? . . . ?x(n?1)?x(n) and x(1)>x(n) is satisfied, where n represents the number of laminations of each of the first and second composition layers, and x(i) represents the value of x in i-th one of the second composition layers as counted from the base substrate side. The second composition layer is coherent to the first composition layer, and the first intermediate layer is coherent to the composition modulation layer.

Abstract: There are provided a heat-insulating member which enhances a thermal efficiency of an engine to enhance fuel efficiency, and a structure of a combustion chamber for the engine. A heat-insulating member 1 includes a substrate 5, an insulating porous layer 3, and a surface dense layer 2. The substrate 5, the insulating porous layer 3 and the surface dense layer 2 are formed of a ceramic material. The surface dense layer 2 has a porosity of 5% or less. Furthermore, the insulating porous layer 3 has a larger porosity than the surface dense layer 2. The substrate 5 sufficiently has a mechanical strength to exist in a self-supported manner. The heat-insulating member 1 is fixed to a piston 14 by mechanical fixing such as screwing or chemical fixing such as brazing.

Abstract: Provided is a semiconductor device of normally-off operation type having a low on-resistance. An epitaxial substrate for it includes: a base substrate; a channel layer made of a first group-III nitride having a composition of Inx1Aly1Gaz1N at least containing Al and Ga and x1=0 and 0?y1?0.3; and a barrier layer made of a second group-III nitride having a composition of Inx2Aly2Gaz2N at least containing In and Al. The composition of the second group-III nitride is, in a ternary phase diagram for InN, AlN, and GaN, in a certain range that is determined in accordance with the composition of the first group-III nitride. The barrier layer has a thickness of 3 nm or less. A low-crystallinity insulating layer is further formed on the barrier layer. The low-crystallinity insulating layer is made of silicon nitride and has a thickness of 3 nm or less.

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: 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: Provided is an epitaxial substrate for a semiconductor device, which has excellent schottky contact characteristics that are stable over time. The epitaxial substrate for a semiconductor device includes a base substrate, a channel layer formed of a first group III nitride containing at least Ga and having a composition of Inx1Aly1Gaz1N (x1+y1+z1=1), and a barrier layer formed of a second group III nitride containing at least In and Al and having a composition of Inx2Aly2Gaz2N (x2+y2+z2=1), wherein the barrier layer has tensile strains in an in-plane direction, and pits are formed on a surface of the barrier layer at a surface density of 5×107/cm2 or more and 1×109/cm2 or less.

Abstract: Provided is an engine combustion chamber structure. Also provided is an inner wall structure for a through channel, through which exhaust gas or intake gas of the engine passes. An engine combustion engine structure is provided with a heat-insulating member on the inner wall of an engine constituent member which constitutes an engine combustion chamber, the heat-insulating member containing a heat-insulating porous layer formed from ceramics, and a surface dense layer formed on the surface of the heat-insulating porous layer and formed from ceramics. The surface dense layer of the heat-insulating member has an open porosity of 5% or less, and preferably the heat-insulating porous layer has a larger open porosity than the open porosity of the surface dense layer.

Abstract: Provided is a crack-free epitaxial substrate having excellent breakdown voltage properties in which a silicon substrate is used as a base substrate thereof. The epitaxial substrate includes: a (111) single crystal Si substrate and a buffer layer including a plurality of composition modulation layers each formed of a first composition layer made of AlN and a second composition layer made of AlxGa1-xN (0?x<1) being alternately laminated. The relationship of x(1)?x(2)? . . . ?x(n?1)?x(n) and x(1)>x(n) is satisfied, where n represents the number of laminations of each of the first and the second composition layer, and x(i) represents the value of x in i-th one of the second composition layers as counted from the base substrate side. Each of the second composition layers is formed so as to be in a coherent state relative to the first composition layer.

Abstract: Provided is an epitaxial substrate for semiconductor device that is capable of achieving a semiconductor device having high reliability in reverse characteristics of schottky junction. An epitaxial substrate for semiconductor device obtained by forming, on a base substrate, a group of group III nitride layers by lamination such that a (0001) crystal plane of each layer is approximately parallel to a substrate surface includes: a channel layer formed of a first group III nitride having a composition of Inx1Aly1Gaz1N (x1+y1+z1=1, z1>0); and a barrier layer formed of a second group III nitride having a composition of Inx2Aly2N (x2+y2=1, x2>0, y2>0), wherein the second group III nitride is a short-range-ordered mixed crystal having a short-range order parameter ? satisfying a range where 0???1.

Abstract: A nitride single crystal is produced on a seed crystal substrate 5 in a melt containing a flux and a raw material of the single crystal in a growing vessel 1. The melt 2 in the growing vessel 1 has temperature gradient in a horizontal direction. In growing a nitride single crystal by flux method, adhesion of inferior crystals onto the single crystal is prevented and the film thickness of the single crystal is made constant.

Abstract: Provided is a crack-free epitaxial substrate having a small amount of warping, in which a silicon substrate is used as a base substrate. The epitaxial substrate includes a (111) single crystal Si substrate, a buffer layer, and a crystal layer. The buffer layer is formed of a first lamination unit and a second lamination unit being alternately laminated. The first lamination unit includes a composition modulation layer and a first intermediate layer. The composition modulation layer is formed of a first unit layer and a second unit layer having different compositions being alternately and repeatedly laminated so that a compressive strain exists therein. The first intermediate layer enhances the compressive strain existing in the composition modulation layer. The second lamination unit is a second intermediate layer that is substantially strain-free.

Abstract: Provided is an epitaxial substrate using a silicon substrate as a base substrate. An epitaxial substrate, in which a group of group-III nitride layers are formed on a (111) single crystal Si substrate such that a (0001) crystal plane of the group of group-III nitride layers is substantially in parallel with a surface of the substrate, includes: a first group-III nitride layer made of AlN with many defects configured of at least one kind from a columnar or granular crystal or domain; a second group-III nitride layer whose interface with the first group-III nitride layer is shaped into a three-dimensional concave-convex surface; and a third group-III nitride layer epitaxially formed on the second group-III nitride layer as a graded composition layer in which the proportion of existence of Al is smaller in a portion closer to a fourth group-III nitride.

Abstract: Provided is an epitaxial substrate capable of achieving a semiconductor device that has excellent schottky contact characteristics as well as satisfactory device characteristics. On a base substrate, a channel layer formed of a first group III nitride that contains at least Al and Ga and has a composition of Inx1Aly1Gaz1N (x1+y1+z1=1) is formed. On the channel layer, a barrier layer formed of a second group III nitride that contains at least In and Al and has a composition of Inx2Aly2Gaz2N (x2+y2+z2=1) is formed such that an In composition ratio of a near-surface portion is smaller than an In composition ratio of a portion other than the near-surface portion.

Abstract: Provided is an epitaxial substrate capable of achieving a semiconductor device that has excellent ohmic contact characteristics as well as satisfactory device characteristics. On a base substrate, a channel layer formed of a first group III nitride that contains at least Al and Ga and has a composition of Inx1Aly1Gaz1N (x1+y1+z1=1) is formed. On the channel layer, a barrier layer formed of a second group III nitride that contains at least In and Al and has a composition of Inx2Aly2Gaz2N (x2+y2+z2=1) is formed such that an In composition ratio of a near-surface portion is larger than an In composition ratio of a portion other than the near-surface portion.

Abstract: Provided is a crack-free epitaxial substrate with reduced warping, in which a silicon substrate is used as a base substrate. The epitaxial substrate includes a (111) single crystal Si substrate, a superlattice layer group in which a plurality of superlattice layers are laminated, and a crystal layer. The superlattice layer is formed of a first unit layer and a second unit layer made of group-III nitrides having different compositions being alternately and repeatedly laminated. The crystal layer is made of a group-III nitride and formed above the base substrate so as to be positioned at an upper side of the superlattice layer group relative to the base substrate. The superlattice layer group has a compressive strain contained therein. In the superlattice layer group, the more distant the superlattice layer is from the base substrate, the greater the compressive strain becomes.