Abstract: The present invention provides a surface acoustic wave device comprising a diamond, having operating frequencies in the range of several hundreds of MHz to several tens of GHz, and being capable of operating at high frequencies. The surface acoustic wave device of the present invention comprises a diamond layer or a substrate layer and a diamond layer, a ZnO piezoelectric layer, interdigital transducers and a short-circuit electrode layer, being characterized in that (2?·H/?M) is in the range of 3.0 to 10.0 where the thickness of the ZnO layer is H and the wavelength of the surface acoustic wave is ?M.

Abstract: A surface acoustic wave (SAW) device that is suitable for mass production and that has excellent operational performance at the superhigh-frequency range. The SAW device comprises (a) a diamond layer 3; (b) a ZnO layer 4, with a thickness of tz, formed on the diamond layer 3; (c) interdigital transducers (IDTs) 5, which excite and receive a SAW, formed on the ZnO layer 4; and (d) an SiO2 layer 6, with a thickness of ts, formed on the ZnO layer 4 so that the SiO2 layer can cover the IDTs 5. The structure of the SAW device is determined by specific numeric ranges of the parameters kh1 and kh2, which are given in equations kh1=3·2&pgr;·(tz/&lgr;) and kh2=3·2&pgr;·(ts/&lgr;), where &lgr; signifies the wavelength of the fundamental wave of the second Sezawa mode of the SAW. The SAW device uses the third harmonic of the second Sezawa mode of the SAW excited.

Abstract: Provided are a substrate for a surface-acoustic-wave device and a surface-acoustic-wave device, in which an intermediate layer for controlling crystal characteristics of a piezoelectric layer does not easily separate from a diamond layer. A surface-acoustic-wave device substrate 20 and a surface-acoustic-wave device 10, according to the present invention, comprises a diamond layer 22, an intermediate layer 24 disposed on the diamond layer 22, and a piezoelectric layer 26 disposed on the intermediate layer 24, the piezoelectric layer 26 being made of LiNbO3 or LiTaO3, the intermediate layer 24 being made of AlN.

Abstract: A surface acoustic wave (SAW) device that is made with diamond, that has high efficiency, and that can be operated at high frequencies, particularly from 9.5 to 10.5 GHz. The SAW device comprises a diamond layer formed singly or formed on a substrate, a ZnO piezoelectric layer, interdigital transducers (IDTs), and a short-circuiting electrode as required. The SAW device has a structure in which the thickness of the ZnO layer, the wavelength of a harmonic of the SAW, and the line width of the IDTs fall in a specified range. With this structure, a large electromechanical coupling coefficient is obtained in a high-frequency range of 10 GHz band by utilizing the third or fifth harmonic of the SAW.

Abstract: A surface acoustic wave (SAW) device that is suitable for mass production and that has excellent operational performance at the superhigh-frequency range. The SAW device comprises (a) a diamond layer 3; (b) a ZnO layer 4, with a thickness of tz, formed on the diamond layer 3; (c) interdigital transducers (IDTs) 5, which excite and receive a SAW, formed on the ZnO layer 4; and (d) an SiO2 layer 6, with a thickness of ts, formed on the ZnO layer 4 so that the SiO2 layer can cover the IDTs 5. The structure of the SAW device is determined by specific numeric ranges of the parameters kh1 and kh2, which are given in equations kh1=3·2&pgr;·(tz/&lgr;) and kh2=3·2&pgr;·(ts/&lgr;), where &lgr; signifies the wavelength of the fundamental wave of the second Sezawa mode of the SAW. The SAW device uses the third harmonic of the second Sezawa mode of the SAW excited.

Abstract: Provided are a substrate for a surface-acoustic-wave device and a surface-acoustic-wave device, in which an intermediate layer for controlling crystal characteristics of a piezoelectric layer does not easily separate from a diamond layer.

Abstract: A surface acoustic wave (SAW) device is provided that is suitable for mass production and that has excellent operational performance at the superhigh-frequency range. The SAW device comprises (a) a diamond layer 3; (b) a ZnO layer 4, with a thickness of tz, formed on the diamond layer 3; (c) interdigital transducers (IDTs) 5, which excite and receive a SAW, formed on the ZnO layer 4; and (d) an SiO2 layer 6, with a thickness of ts, formed on the ZnO layer 4 so that the SiO2 layer can cover the IDTs 5. The structure of the SAW device is determined by specific numeric ranges of the parameters kh1 and kh2, which are given in equations kb1=5·2&pgr;·(tz/&lgr;) and kh2=5·2&pgr;·(ts/&lgr;), where &lgr; signifies the wavelength of the fundamental wave of the second mode of the SAW. The SAW device uses the fifth harmonic of the second mode of the SAW.

Abstract: A surface acoustic wave (SAW) device is provided that is suitable for mass production and that has excellent operational performance at the superhigh-frequency range. The SAW device comprises (a) a diamond layer 3; (b) a ZnO layer 4, with a thickness of tz, formed on the diamond layer 3; (c) interdigital transducers (IDTs) 5, which excite and receive a SAW, formed on the ZnO layer 4; and (d) an SiO2 layer 6, with a thickness of ts, formed on the ZnO layer 4 so that the SiO2 layer can cover the IDTs 5. The structure of the SAW device is determined by specific numeric ranges of the parameters kh1 and kh2, which are given in equations kh1=5·2&pgr;·(tz/&lgr;) and kh2=5·2&pgr;(ts/&lgr;), where &lgr; signifies the wavelength of the fundamental wave of the second mode of the SAW. The SAW device uses the fifth harmonic of the second mode of the SAW.

Abstract: A surface-acoustic-wave (SAW) device that has not only an increased propagation velocity of SAWs but also an increased electromechanical coupling coefficient of 20% or more. The SAW device comprises a diamond substrate 10, a KNbO3 layer 30, and IDTs 40. The KNbO3 layer 30 is composed of a single crystal having the layer thickness and the crystal orientation that are controlled so as to obtain a propagation velocity of 5,000 m/s or more and an electromechanical coupling coefficient of 20% or more for the SAW in a specified mode.

Abstract: A diamond base material for surface acoustic wave device, which includes: a low-resistivity base material, and a high-resistivity diamond layer having a thickness of 5-50 .mu.m disposed on the low-resistivity base material.

Abstract: A diamond base material for surface acoustic wave device, which includes: a low-resistivity base material, and a high-resistivity diamond layer having a thickness of 5-50 .mu.m disposed on the low-resistivity base material.

Abstract: A diamond base material for surface acoustic wave device, which includes: a low-resistivity base material, and a high-resistivity diamond layer having a thickness of 5-50 .mu.m disposed on the low-resistivity base material.

Abstract: The present invention directed to a SAW device comprising a diamond layer and an LiTaO.sub.3 layer, which can be operated at the frequency of 3 GHz or higher, with superior durability and less energy loss. The SAW device for 1st mode surface acoustic wave of a wavelength .lambda. (.mu.m) according to the present invention comprises: a diamond layer, an interdigital transducer formed onto the diamond layer, and a polycrystalline C-axis-oriented LiTaO.sub.3 layer formed over the interdigital transducer; wherein the SAW device satisfies a relationship of 0.4.ltoreq.kh.sub.1 .ltoreq.1.2, where a parameter kh.sub.1 is defined as kh.sub.1 =2.pi.(t.sub.1 /.lambda.), and t.sub.1 (.mu.m) is the thickness of the LiTaO.sub.3 layer.

Abstract: An orientational material including: diamond, and a ZnO film disposed on a surface of (111) orientational diamond provided by the diamond. Such an orientational material may suitably be used as a component for fabricating a surface acoustic wave device utilizing diamond.

Abstract: A SAW device which includes at least, diamond, an LiNbO.sub.3 layer disposed on the diamond, and an IDT provided so as to contact the LiNbO.sub.3 layer; and utilizes SAW of an "n-th" mode (n=0, 1 or 2) having a wavelength of .lambda..sub.n (.mu.m), wherein a parameter of kh.sub.1 =2.pi.(t.sub.1 /.lambda..sub.n) is in a specific range provided that the thickness of the LiNbO.sub.3 layer is denoted by t.sub.1 (.mu.m).

Abstract: A diamond substrate having a smooth surface, including a polycrystalline diamond film having a surface with a pit, and an insulating material other than diamond, which occupies the pit.

Abstract: A surface acoustic wave element has a diamond layer, a piezoelectric thin film formed on the diamond layer, and a pair of electrodes for generating a surface acoustic wave having a specific wavelength and extracting the surface acoustic wave, wherein at least one electrode is a copper electrode epitaxially grown on the surface of the diamond layer. To manufacture this surface acoustic wave element, after the diamond layer is formed on a substrate by epitaxial growth, the copper electrodes each having the predetermined shape are formed on the surface of the diamond layer by epitaxial growth. Since the copper electrodes formed on the diamond layer consist of high-quality single crystal copper, resistances to electromigration and stress migrations can be increased. As a result, there is provided an excellent surface acoustic wave element free from electrical defects caused by degradation and failure of the copper electrodes or free from degradation of the electrical characteristics.

Abstract: A layer of boron nitride which is relatively easily workable is positioned in a stacked structure in close contact with a piezoelectric member, to provide a surface acoustic wave device which can be driven in a higher frequency range. Such a surface acoustic device (10) has a substrate (1), a boron nitride film (2) formed on the substrate (1), and a pair of interdigital electrodes (3a, 3b) formed on the boron nitride film (2). The interdigital electrodes (3a, 3b) are covered with a piezoelectric film (4), which is in close contact with the boron nitride film (2).

Abstract: A surface acoustic wave element includes a hard layer containing a composition component essentially consisting of at least one of diamond and a diamond-like carbon film, a piezoelectric layer formed on the hard layer, a silicon dioxide (SiO.sub.2) layer formed on the piezoelectric layer, and electrodes combined with the piezoelectric layer to perform electro-mechanical conversion. The surface acoustic wave element has a larger electro-mechanical coupling coefficient and a higher surface acoustic wave propagation velocity than does a conventional surface acoustic wave element having no silicon dioxide layer, thereby obtaining a surface acoustic wave element that can operate in a high-frequency range. In particular, the electro-mechanical coupling coefficient is increased. The SiO.sub.2 layer is an electric insulator and rarely reacts with moisture or acids. The SiO.sub.

Abstract: A surface acoustic wave device includes a hard layer comprising diamond or a diamond-like carbon film, and a piezoelectric layer formed on the hard layer. It further includes a paired interdigital transducer and grounding electrode, which perform an electro-mechanical conversion, with the piezoelectric layer arranged therebetween. Then, the feature of the present invention is to form the grounding electrode of a conductive oxide. It is preferred that the conductive oxide is formed by doping an impurity into a piezoelectric material of ZnO. Therefore, the adhesion between the piezoelectric layer and the hard layer, and the grounding electrodes is increased, so that the device yield is enhanced, and a high electromechanical coupling coefficient can be achieved in a high frequency range.