Design and Fabrication of Ta filled microcavites in the delay paths of SAW devices for improved power transfer

Journal Article · Sun Mar 01 04:00:00 EST 2015 · Journal of vacuum science & technology. B, Microelectronics and nanometer structures

DOI:https://doi.org/10.1116/1.4906515· OSTI ID:1396171

Richardson, Mandek; Bhethanabotla, V. R.

The authors report the design and fabrication of a surface acoustic wave (SAW) device with improved power transfer due to modification of its delay path. Typically, SAW delay-line devices suffer from relatively high insertion loss (IL) (similar to 10-30 dB). Our approach is to incorporate an array of microcavities, having square cross-sectional area (lambda/2 x lambda/2) and filled with tantalum, within the delay path to maximize acoustic confinement to the surface and reduce IL. To determine the effectiveness of the cavities without expending too many resources and to explain trends found in actual devices, a finite element model of a SAW device with tantalum filled cavities having various depths was utilized. For each depth simulated, IL was decreased compared to a standard SAW device. Microcavities 2.5 mu m deep filled with tantalum showed the best performance (Delta IL = 17.93 dB). To validate simulated results, the authors fabricated a SAW device on ST 90 degrees-X quartz with microcavities etched into its delay path using deep reactive ion etching and filled with tantalum. Measurement of fabricated devices showed inclusion of tantalum filled microcavities increased power transfer compared to a device without cavities. (C) 2015 American Vacuum Society.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE Office of Science - Office of Basic Energy Sciences - Scientific User Facilities Division
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1396171
• Journal Information: Journal of vacuum science & technology. B, Microelectronics and nanometer structures, Journal Name: Journal of vacuum science & technology. B, Microelectronics and nanometer structures Journal Issue: 2 Vol. 33; ISSN 1071-1023
• Country of Publication: United States
• Language: English