Surface acoustic wave device, substrate therefor, and method of manufacturing the substrate
US6183555A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 11, 1999 |
| Grant date | Feb 6, 2001 |
| Priority date | — |
| Expiry date | May 11, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/02543
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A sapphire single crystal wafer 11 having a diameter not less than two inches and having an off-angled surface which is obtained by rotating an R (1-102) surface about a [11-20] axis by a given off-angle is introduced in a CVD apparatus, and a double-layer structure of first and second aluminum single crystal layers 12 and 13 is deposited on the off-angled surface of the sapphire single crystal wafer by MOCVD. The thus deposited aluminum single crystal layer 13 has (1-210) surface. The first aluminum nitride single crystal layer 12 serves as a buffer layer and has a thickness of 5-50 nm, and the second aluminum nitride single crystal layer 13 has a thickness not less than 1 .mu.m. The off-angle is preferably set to a value not less than .+-.1.degree., much preferably a value .+-.2.degree., more preferably a value not less than -3.degree., and particularly preferable to a value within a range from -2.degree.-+10.degree.. The thus obtained aluminum nitride single crystal layer 12, 13 has no clack formed therein, has an excellent piezo-electric property, and has a high propagating velocity for surface acoustic wave.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.