Abstract: A bonded body includes a supporting substrate, a silicon oxide layer provided on the supporting substrate, and a piezoelectric material substrate provided on the silicon oxide layer and composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate. The surface resistivity of the piezoelectric material substrate on the side of the silicon oxide layer is 1.7×101 5?/? or higher.

Abstract: A bonded body includes a supporting substrate, a silicon oxide layer provided on the supporting substrate, and a piezoelectric material substrate provided on the silicon oxide layer and composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate. An average value of a nitrogen concentration of the silicon oxide layer is higher than a nitrogen concentration at an interface between the silicon oxide layer and supporting substrate and higher than a nitrogen concentration at an interface between the silicon oxide layer and piezoelectric material substrate.

Abstract: A bonded body includes a supporting substrate, a piezoelectric material substrate of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate, and a bonding layer bonding the supporting substrate and piezoelectric material substrate. The material of the bonding layer is silicon oxide. Provided that the bonding layer is divided into a piezoelectric material substrate-side bonding part and supporting substrate-side bonding part, the piezoelectric material substrate-side bonding part has a nitrogen concentration higher than a nitrogen concentration of the supporting substrate-side bonding part.

Abstract: A silicon film is provided on a supporting substrate composed of silicon by sputtering method. The silicon film is subjected to heat treatment at a temperature of 400° C. or higher and 600° C. or lower to generate an intermediate layer. The piezoelectric material substrate is bonded to the supporting substrate through a bonding layer of silicon oxide and the intermediate layer.

Abstract: A bonded body includes a supporting substrate, silicon oxide layer provided on the supporting substrate, and a piezoelectric material substrate provided on the silicon oxide layer and composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalite. A nitrogen concentration at an interface between the piezoelectric material substrate and silicon oxide layer is higher than a nitrogen concentration at an interface between the silicon oxide layer and the supporting substrate.

Abstract: A piezoelectric monocrystalline substrate is composed of a material represented by LiAO3 (A represents at least one element selected from the group consisting of niobium and tantalum), a bonding layer is compose of a material of an oxide of at least one element selected from the group consisting of niobium and tantalum, and an interface layer is provided along an interface between the piezoelectric monocrystalline substrate 6 and bonding layer, and the interface layer has a composition of ExO(1-x) (E represents at least one element selected from the group consisting of niobium and tantalum and 0.29?x?0.89).

Abstract: In the composite substrate 10, the piezoelectric substrate 12 and the support substrate 14 are bonded by direct bonding using an ion beam. One surface of the piezoelectric substrate 12 is a negatively-polarized surface 12a and another surface of the piezoelectric substrate 12 is a positively-polarized surface 12b. An etching rate at which the negatively-polarized surface 12a is etched with a strong acid may be higher than an etching rate at which the positively-polarized surface 12b is etched with the strong acid. The positively-polarized surface 12b of the piezoelectric substrate 12 is directly bonded to the support substrate 14. The negatively-polarized surface 12a of the piezoelectric substrate 12 may be etched with the strong acid.

Abstract: In the composite substrate, the piezoelectric substrate and the support substrate are bonded by direct bonding using an ion beam. One surface of the piezoelectric substrate is a negatively-polarized surface and another surface of the piezoelectric substrate is a positively-polarized surface. An etching rate at which the negatively-polarized surface is etched with a strong acid may be higher than an etching rate at which the positively-polarized surface is etched with the strong acid. The positively-polarized surface of the piezoelectric substrate is directly bonded to the support substrate. The negatively-polarized surface of the piezoelectric substrate may be etched with the strong acid.

Abstract: In the composite substrate 10, the piezoelectric substrate 12 and the support substrate 14 are bonded by direct bonding using an ion beam. One surface of the piezoelectric substrate 12 is a negatively-polarized surface 12a and another surface of the piezoelectric substrate 12 is a positively-polarized surface 12b. An etching rate at which the negatively-polarized surface 12a is etched with a strong acid may be higher than an etching rate at which the positively-polarized surface 12b is etched with the strong acid. The positively-polarized surface 12b of the piezoelectric substrate 12 is directly bonded to the support substrate 14. The negatively-polarized surface 12a of the piezoelectric substrate 12 may be etched with the strong acid.

Abstract: A composite substrate according to the present invention includes a piezoelectric substrate that is a single-crystal lithium tantalate or lithium niobate substrate, a support substrate that is a single-crystal silicon substrate, and an amorphous layer joining together the piezoelectric substrate and the support substrate. The amorphous layer contains 3 to 14 atomic percent of argon. The amorphous layer includes, in order from the piezoelectric substrate toward the composite substrate, a first layer, a second layer, and a third layer. The first layer contains a larger amount of a constituent element (such as tantalum) of the piezoelectric substrate than the second and third layers. The third layer contains a larger amount of a constituent element (silicon) of the support substrate than the first and second layers. The second layer contains a larger amount of argon than the first and third layers.

Abstract: The present invention provides a composite substrate comprising a piezoelectric substrate that is a single-crystal lithium tantalate or lithium niobate substrate, a support substrate that is a single-crystal silicon substrate, and an amorphous layer containing argon and joining together the piezoelectric substrate and the support substrate. The amorphous layer includes, in order from the piezoelectric substrate toward the composite substrate, a first layer, a second layer, and a third layer. The first layer contains a larger amount of a constituent element of the piezoelectric substrate than the second and third layers, the third layer contains a larger amount of a constituent element of the support substrate than the first and second layers, and the second layer contains a larger amount of argon than the first and third layers.

Abstract: A composite substrate according to the present invention includes a piezoelectric substrate that is a single-crystal lithium tantalate or lithium niobate substrate, a support substrate that is a single-crystal silicon substrate, and an amorphous layer joining together the piezoelectric substrate and the support substrate. The amorphous layer contains 3 to 14 atomic percent of argon. The amorphous layer includes, in order from the piezoelectric substrate toward the composite substrate, a first layer, a second layer, and a third layer. The first layer contains a larger amount of a constituent element (such as tantalum) of the piezoelectric substrate than the second and third layers. The third layer contains a larger amount of a constituent element (silicon) of the support substrate than the first and second layers. The second layer contains a larger amount of argon than the first and third layers.

Abstract: The present invention provides a composite substrate comprising a piezoelectric substrate that is a single-crystal lithium tantalate or lithium niobate substrate, a support substrate that is a single-crystal silicon substrate, and an amorphous layer containing argon and joining together the piezoelectric substrate and the support substrate. The amorphous layer includes, in order from the piezoelectric substrate toward the composite substrate, a first layer, a second layer, and a third layer. The first layer contains a larger amount of a constituent element of the piezoelectric substrate than the second and third layers, the third layer contains a larger amount of a constituent element of the support substrate than the first and second layers, and the second layer contains a larger amount of argon than the first and third layers.