Abstract: A bonded body includes a supporting substrate, a piezoelectric single crystal substrate and a bonding layer provided between the supporting substrate and piezoelectric single crystal substrate. The bonding layer has a composition of Si(1-x)Ox (x represents an oxygen ratio). The oxygen ratio x at a central part in a thickness direction of the bonding layer is higher than an oxygen ratio x at an end part of the bonding layer on a side of the piezoelectric single crystal substrate and an oxygen ratio x at an end part of the bonding layer on a side of the supporting substrate. The oxygen ratio at the central part in the thickness direction of the bonding layer is 0.013 or higher and 0.666 or lower.

Abstract: A composite substrate for an electro-optic element is disclosed. The composite substrate includes: an electro-optic crystal substrate having an electro-optic effect; a low-refractive-index layer being in contact with the electro-optic crystal substrate and having a lower refractive index than the electro-optical crystal substrate; and a support substrate bonded to the low-refractive-index layer at least via a bonding layer. A plurality of interfaces located between the low-refractive-index layer and the support substrate includes at least one rough interface having a roughness that is larger than a roughness of an interface between the electro-optic crystal substrate and the low-refractive-index layer.

Abstract: A phosphor element includes: a phosphor part having an incident face of the excitation light, an opposing face opposing the incident face, and a side face, the phosphor part converting at least a part of the excitation light incident onto the incident face into the fluorescence and emitting the fluorescence from the incident face; an integral low refractive index layer on the side face and opposing face of the phosphor part and having a refractive index lower than that of the phosphor part; and an integral reflection film covering a surface of the low refractive index layer. The area of the incident face of the phosphor part is larger than the area of the opposing face.

Abstract: A bonded body includes: a piezoelectric single crystal substrate; a supporting substrate composed of a single crystal silicon; a bonding layer provided between the supporting substrate and piezoelectric single crystal substrate and having a composition of Si(1-x)Ox (0.008?x?0.408); and an amorphous layer provided between the supporting substrate and bonding layer and containing silicon atoms, oxygen atoms and argon atoms. The concentration of the oxygen atoms in an end part of the amorphous layer on a side of the bonding layer is higher than the average concentration of the oxygen atoms in the bonding layer.

Abstract: A bonded body includes a piezoelectric single crystal substrate; a supporting substrate composed of a polycrystalline ceramic material or a single crystal material; a bonding layer provided on the piezoelectric single crystal substrate and having a composition of Si(1-x)Ox (0.008?x?0.408); and an amorphous layer provided between the supporting substrate and bonding layer, the amorphous layer containing oxygen atoms and argon atoms. A concentration of the oxygen atoms at a central part of the amorphous layer is higher than a concentration of the oxygen atoms at a peripheral part of the amorphous layer.

Abstract: A bonded body for an optical modulator includes a supporting substrate, an optical waveguide material provided on the supporting substrate and composed of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate, and an optical waveguide in the optical waveguide material. The supporting substrate is composed of a material selected from the group consisting of magnesium oxide and a magnesium-silicon composite oxide.

Abstract: A bonded body includes a supporting substrate composed of a polycrystalline ceramic material or monocrystalline material, a piezoelectric single crystal substrate and a bonding layer provided between the supporting substrate and piezoelectric single crystal substrate. The bonding layer has a composition of Si(1-x)Ox (x represents an oxygen ratio). The oxygen ratio is increased or decreased from an end part of the bonding layer on the side of the piezoelectric single crystal substrate to an end part of the bonding layer on the side of the supporting substrate. The maximum value of the oxygen ratio x in the bonding layer is 0.013 or higher and 0.666 or lower, and the minimum value of the oxygen ratio is 0.001 or higher and 0.408 or lower.

Abstract: A bonded body includes a supporting substrate, a piezoelectric single crystal substrate and a bonding layer provided between the supporting substrate and piezoelectric single crystal substrate. The bonding layer has a composition of Si(1-x)Ox (x represents an oxygen ratio). The oxygen ratio x at a central part in a thickness direction of the bonding layer is higher than an oxygen ratio x at an end part of the bonding layer on a side of the piezoelectric single crystal substrate and an oxygen ratio x at an end part of the bonding layer on a side of the supporting substrate. The oxygen ratio at the central part in the thickness direction of the bonding layer is 0.013 or higher and 0.666 or lower.

Abstract: A bonded body includes a supporting body composed of a ceramic, a bonding layer provided over a surface of the supporting body and composed of one or more material selected from the group consisting of mullite, alumina, tantalum pentoxide, titanium oxide and niobium pentoxide, and a piezoelectric single crystal substrate bonded with the bonding layer. The surface of the supporting body has an arithmetic average roughness Ra of 0.5 nm or larger and 5.0 nm or smaller.

Abstract: An acoustic wave device includes a piezoelectric material substrate, an intermediate layer on the piezoelectric material substrate and composed of one or more materials selected from the group consisting of silicon oxide, aluminum nitride and sialon, a bonding layer on the intermediate layer and composed of one or more materials selected from the group consisting of tantalum pentoxide, niobium pentoxide, titanium oxide, mullite, alumina, a high resistance silicon and hafnium oxide, a supporting body composed of a polycrystalline ceramic and bonded to the bonding layer by direct bonding, and an electrode on the piezoelectric material substrate.

Abstract: An object is to improve insulation in a bonding layer and to improve a bonding strength of a supporting body and piezoelectric single crystal substrate, in a bonded body having the supporting body made of a polycrystalline material or single crystal material, the piezoelectric single crystal substrate and the bonding layer provided between the supporting body and piezoelectric single crystal substrate, wherein the bonded body includes the supporting body, piezoelectric single crystal substrate and the bonding layer provided between the supporting body and piezoelectric single crystal substrate, and the bonding layer has a composition of Si(1-x)Ox (0.008?x?0.408).

Abstract: A bonded body includes a supporting body composed of a ceramic, a bonding layer provided over a surface of the supporting body and composed of one or more material selected from the group consisting of mullite, alumina, tantalum pentoxide, titanium oxide and niobium pentoxide, and a piezoelectric single crystal substrate bonded with the bonding layer. The surface of the supporting body has an arithmetic average roughness Ra of 0.5 nm or larger and 5.0 nm or smaller.

Abstract: An object is to improve insulation in a bonding layer and to improve a bonding strength of a supporting body and piezoelectric single crystal substrate, in a bonded body having the supporting body made of a polycrystalline material or single crystal material, the piezoelectric single crystal substrate and the bonding layer provided between the supporting body and piezoelectric single crystal substrate. The bonded body includes the supporting body, piezoelectric single crystal substrate and the bonding layer provided between the supporting body and piezoelectric single crystal substrate. The bonding layer has a composition of Si(1-x)Ox (0.008?x?0.408).