Surface acoustic wave device, shear bulk wave transducer, and longitudinal bulk wave transducer
First Claim
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1. A surface acoustic wave device comprising:
- a substrate;
an electrode disposed on the substrate, having a specific resistance of up to about 1 Ω
·
cm, and including a ZnO layer with a low resistance, having an impurity doping the ZnO;
a piezoelectric film arranged as an epitaxial film on the electrode including the ZnO layer, and having a specific resistance of at least about 106 Ω
·
cm and a lattice constant within approximately ±
20% of that of ZnO; and
an interdigital electrode disposed on the piezoelectric film;
wherein the substrate is made of a material selected from the group consisting of R-plane sapphire, c-plane sapphire, sapphire having a plane parallel to a c axis, (111), (100) or (011) silicon, Z-cut quartz, approximately 30°
to approximately 42°
rotated Y-plate LiNbO3, and approximately 30°
to approximately 42°
rotated Y-plate LiTaO3.
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Abstract
A surface acoustic wave device includes a substrate and electrode disposed on the substrate. The electrode has a specific resistance ρ of up to about 1 Ω·cm and is made of a ZnO film with a low resistance having an impurity doping. A piezoelectric film having a specific resistance ρ of at least about 106 Ω·cm and a lattice constant within approximately ±20% of that of ZnO is disposed on the electrode. An interdigital electrode is disposed on the piezoelectric film.
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Citations
11 Claims
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1. A surface acoustic wave device comprising:
-
a substrate;
an electrode disposed on the substrate, having a specific resistance of up to about 1 Ω
·
cm, and including a ZnO layer with a low resistance, having an impurity doping the ZnO;
a piezoelectric film arranged as an epitaxial film on the electrode including the ZnO layer, and having a specific resistance of at least about 106 Ω
·
cm and a lattice constant within approximately ±
20% of that of ZnO; and
an interdigital electrode disposed on the piezoelectric film;
whereinthe substrate is made of a material selected from the group consisting of R-plane sapphire, c-plane sapphire, sapphire having a plane parallel to a c axis, (111), (100) or (011) silicon, Z-cut quartz, approximately 30°
to approximately 42°
rotated Y-plate LiNbO3, and approximately 30°
to approximately 42°
rotated Y-plate LiTaO3.- View Dependent Claims (2, 3, 4, 5, 6)
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7. A shear bulk wave transducer comprising:
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a substrate made of one material selected from the group consisting of approximately 30°
to approximately 42°
rotated Y-plate LiNbO3 and approximately 30°
to approximately 42°
rotated Y-plate LiTaO3;
an electrode disposed on the substrate, having a specific resistance of up to about 1 Ω
·
cm, and made of a ZnO film with a low resistance, having an atom or molecule belonging to group IIIA, IIIB, VA, or VB as an impurity doping the ZnO;
a piezoelectric film arranged as an epitaxial layer on the electrode made of the ZnO with a low resistance, and having a specific resistance ρ
of at least about 106 Ω
·
cm, and a lattice constant within approximately ±
20% of that of ZnO; and
an electrode disposed on the piezoelectric film. - View Dependent Claims (8, 9)
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10. A longitudinal bulk wave transducer comprising:
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a substrate made of a material selected from the group consisting of sapphire having a plane parallel to the c axis, c-plane sapphire, Z-cut quartz, and (111), (100) or (011) silicon;
an electrode disposed on the substrate, having a specific resistance of up to about 1 Ω
·
cm, and made of a ZnO film with a low resistance having as an impurity an atom or molecule belonging to group IIIA, IIIB, VA, or VB, doping the ZnO;
a piezoelectric film arranged as an epitaxial film on the electrode made of the ZnO with a low resistance, and having a specific resistance of at least about 106 Ω
·
cm, and a lattice constant within approximately ±
20% of that of ZnO; and
an electrode disposed on the piezoelectric film. - View Dependent Claims (11)
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Specification