Elastic boundary wave device and method of its manufacture
AssigneeKabushiki Kaisha Toshiba
InventorNaoyuki Mishima
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Abstract
A boundary wave device and a fabrication method thereof that allow the conversion efficiency of a boundary wave excited by electrodes to be improved and prevents the device from being affected by parasitical resistance between the electrodes are provided. interdigital transducers 3 are formed on a main surface of a piezoelectric first substrate 2. A dielectric film 5 is formed on a main surface of the first substrate 2 so that the dielectric film 5 coats the interdigital transducers 3 and has a smooth surface 4. A Si second substrate 6 is layered on the dielectric film 5.
Claims12
A boundary wave device, comprising:
- a first substrate formed of a piezoelectric material and having a main surface;
- a plurality of electrodes, formed on the main surface of said first substrate, for exciting a boundary wave;
- a dielectric film formed on said first substrate so as to completely cover said plurality of electrodes and having a smooth surface;
- and
- a second substrate layered on, to directly bond to, the smooth surface of said dielectric film.
A fabrication method for a boundary wave device, comprising the steps of:
- (a) forming a plurality of electrodes for exciting a boundary wave on a main surface of a piezoelectric first substrate;
- (b) forming a dielectric film on the main surface of the first substrate with the plurality of electrodes so as to completely cover the plurality of electrodes;
- (c) smoothing the surface of the dielectric film formed on the main surface of the piezoelectric first substrate;
- and
- (d) layering a second substrate on the surface of the smoothed dielectric film.
Dependencies are inferred from the claim text.