AVS 66th International Symposium & Exhibition
    MEMS and NEMS Group Monday Sessions
       Session MN-MoM

Paper MN-MoM5
2D Raman Imaging and Characterization of Surface Acoustic Waves on GaAs Substrates

Monday, October 21, 2019, 9:40 am, Room A210

Session: MEMS, BioMEMS, and MEMS for Energy: Processes, Materials, and Devices I
Presenter: Brian Douglas Rummel, University of New Mexico
Authors: B.D. Rummel, University of New Mexico
G. Heileman, University of New Mexico
M.D. Henry, Sandia National Laboratories
S.M. Han, University of New Mexico
Correspondent: Click to Email
We have fabricated Surface Acoustic Wave (SAW) devices on a GaAs (110) substrate to demonstrate the capability of 2D Raman microscopy to image and characterize acoustic waves traveling on the surface of a piezoelectric substrate. SAW devices are typically utilized in sensors and rf filters, and developing a facile technique to image the transmitted signal would be useful in characterizing device operation and optimization. SAWs are generated using a two-port interdigital transducer (IDT) platform, modified to produce free surface standing waves. These standing waves provide a means to differentiate nodes and antinodes of the acoustic wave. The frequency of SAWs does not easily allow in situ, real-time imaging of the waves. However, we make use of Raman peak broadening that corresponds to an averaging of the peak shifts over the integration time of the spectrometer. We have derived an analytical model to fit the peak broadening and effectively calculate the maximum strain induced by the acoustic waves, thus allowing one to characterize the SAWs and measure surface displacements on the order of picometers. The application of this research for the strain-induced fabrication of highly ordered nano/micro structures in III-V semiconductors will also be discussed.