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US 6,937,114 B2Granted
Surface acoustic wave device, electronic component using the device, and composite module
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsMitsuhiro Furukawa, Kiyoharu Yamashita, Hiroshi Kurotake, Hiroyoshi Sekiguchi
Life of this patent
Estimating the term…
Abstract
A surface acoustic wave device includes a piezoelectric substrate and an electrode provided on the substrate. The electrode includes a first metal layer provided on the piezoelectric substrate and having a trapezoid shape in the cross section and a second metal layer provided over the piezoelectric substrate at the same position as the first metal layer over the piezoelectric substrate. By controlling the shape of side surfaces of the electrode, the surface acoustic wave device hardly vary in a propagation frequency.
Claims57
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- and
- an electrode including
- a first metal layer provided on said piezoelectric substrate and having a trapezoid shape in a cross section, and
- a second metal layer provided over said piezoelectric substrate at a same position as said first metal layer,
- wherein said piezoelectric substrate is etched to a depth not greater than 10 nm at a portion where said electrode is not formed thereon.
3 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- and
- an electrode including
- a first metal layer provided over said piezoelectric substrate and having a cross section of a rectangular shape, and
- a second metal layer provided over said first metal layer and being wider than said first metal layer,
- wherein a side surface of said second metal layer has an undulation smaller than a side surface of said first metal layer.
3 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- and
- an electrode including
- a first metal layer provided over said piezoelectric substrate and having a cross section of a rectangular shape, and
- second metal layer provided over said first metal layer and being wider than said first metal layer,
- wherein said piezoelectric substrate has a portion etched to a depth not greater than 10 nm where said electrode is not formed thereon.
3 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- and
- an electrode including
- a first metal layer provided over said piezoelectric substrate and having a cross section of a rectangular shape, and
- a second metal layer provided over said first metal layer and being wider than said first metal layer,
- wherein a side surface of said electrode has an undulation not greater than 5 nm.
3 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- and
- an electrode including
- a first metal layer provided over said piezoelectric substrate and having a cross section of a rectangular shape, and
- a second metal layer provided over said first metal layer and being wider than said first metal layer,
- wherein a interlayer difference between respective side surfaces of said first metal layer and said second metal layer is not greater than 5 nm.
3 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- and
- an electrode including
- a first metal layer provided over said piezoelectric substrate and having a cross section of a rectangular shape, and
- a second metal layer provided over said first metal layer and being wider than said first metal layer,
- wherein a width (A) of an uppermost of said electrode distanced farthest from said piezoelectric substrate and a width (L) of a lowermost of said electrode closest to said piezoelectric substrate satisfy that A/L ranges from 0.98 to 1.01.
3 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate
- an electrode provided on said piezoelectric substrate and having a projection provided on a side surface thereof, said electrode including
- a first metal layer, and
- a second metal layer provided on said first metal layer;
- a protective layer for covering at least an upper surface and said side surface of said electrode;
- and
- a third metal layer provided between said first metal layer and said piezoelectric substrate.
4 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- an electrode including
- a first metal layer provided on said piezoelectric substrate and having a trapezoid shape in a cross section, and
- a second metal layer provided over said piezoelectric substrate at a same position as said first metal layer;
- and
- another electrode provided on said piezoelectric substrate,
- wherein a width (L) of a lowermost of said electrode is L and a distance (S) between said electrode and said another electrode satisfy that L/(L+S) ranges from 0.58 to 0.65.
4 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- and
- an electrode including
- a first metal layer provided on said piezoelectric substrate and having a trapezoid shape in a cross section, and
- a second metal layer provided over said piezoelectric substrate at a same position as said first metal layer,
- wherein a width (A) of an uppermost of said electrode farthest from said piezoelectric substrate and a width (L) of a lowermost of said electrode closest to said piezoelectric substrate satisfy that A/L ranges from 1.1 to 1.3.
3 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- an electrode provided on said piezoelectric substrate and having a projection provided on a side surface thereof, said electrode including
- a first metal layer, and
- a second metal layer provided on said first metal layer;
- and
- a protective layer for covering at least an upper surface and said side surface of said electrode,
- wherein a cross section of said first metal layer has a trapezoid shape.
4 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- and
- an electrode including
- a first metal layer provided on said piezoelectric substrate and having a trapezoid shape in a cross section, and
- a second metal layer provided over said piezoelectric substrate at a same position as said first metal layer,
- wherein a side surface of said second metal layer has an undulation smaller than a side surface of said first metal layer.
3 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- and
- an electrode including
- a first metal layer provided on said piezoelectric substrate and having a trapezoid shape in a cross section, and
- a second metal layer provided over said piezoelectric substrate at a same position as said first metal layer
- wherein a side surface of said electrode has an undulation not greater than 5 nm.
3 more elements
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- and
- an electrode including
- a first metal layer provided on said piezoelectric substrate and having a trapezoid shape in a cross section, and
- a second metal layer provided over said piezoelectric substrate at a same position as said first metal layer,
- wherein an interlayer difference between respective side surfaces of said first metal layer and said second metal layer is not greater than 5 nm.
3 more elements
Dependencies are inferred from the claim text.