High power SAW filter with new Al-Sc-Cu/Ti/Al-Sc-Cu/Ti electrodes

Abstract

High power SAW filters using newly developed Al-Sc-Cu/Ti/Al-Sc-Cu/Ti electrodes have been successfully achieved. The thickness of this new film can be controlled during the deposition process as easily as when using conventional Al-Cu alloy film, and this film can be formed into Inter Digital Transducer (IDT) electrodes using conventional Reactive Ion Etching (RIE). We evaluated the power durability of receiver top filters using the new electrodes. Results indicate that the lifetime of the new electrode system exceeds 900,000 hours at an ambient temperature of 85/spl deg/C and input power of 3l dBm, about 1,000,000 times longer under these conditions than conventional Al-Cu alloy electrode systems. The new electrodes have clear potential for use in Advanced Mobile Phone Service (AMPS) and code division multiple access (CDMA) system SAW duplexers.