The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 27, 1997
Filed:
Sep. 28, 1995
Applicant:
Inventor:
Seiki Goto, Itami, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03H / ;
U.S. Cl.
CPC ...
333193 ; 3103 / ;
Abstract
A surface acoustic wave (SAW) filter includes a monocrystalline substrate, such as sapphire, having a surface and an epitaxial piezoelectric layer disposed on the surface of the substrate. The piezoelectric layer is a semiconductor material that is relatively heavily doped in regions at the interface between the substrate and the piezoelectric layer. The heavily doped regions functions as electrodes. Because the electrodes at the interface are made of the same material as the piezoelectric layer, there is no disturbance of the crystallinity of the piezoelectric layer during its deposition and thermal stresses during use are substantially reduced.