Broad band surface acoustic wave edge deposited transducer
US4447754A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 24, 1982 |
| Grant date | May 8, 1984 |
| Priority date | — |
| Expiry date | Sep 24, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/14502
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A broad band surface acoustic wave (SAW) device has an edge-deposited transducer (EDT) capable of frequencies in excess of 1 GHz and bandwidths in the hundreds of MHz. The device includes a transducer on a semiconductor substrate which is either non-piezoelectric or weakly piezoelectric. The substrate has a sharp, smooth edge formed by the intersection of its top and a side surface. The transducer includes a passivation layer deposited on the side surface of the substrate and a starter layer deposited on the passivation layer; an inner metallic (gold, for example) electrode deposited on the starter layer; a transducer layer deposited on the inner metallic electrode; and an outer metallic electrode deposited on the transducer layer. The outer electrode is formed on the transducer layer one-fifth wavelength below the top surface of the substrate. When the transducer is excited, bulk longitudinal waves are generated in the transducer layer which couple to the longitudinal component of the surface wave in the substrate causing the SAW mode to propagate away from the transducer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.