Imaging of surface acoustic waves on GaAs using 2D confocal Raman microscopy and atomic force microscopy

• Published in: Applied physics letters Vol. 118; no. 3
• Main Authors: Rummel, Brian Douglas, Miroshnik, Leonid, Patriotis, Marios, Li, Andrew, Sinno, Talid R., Henry, Michael David, Balakrishnan, Ganesh, Han, Sang M.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 18-01-2021; American Institute of Physics (AIP)
• Subjects: acoustic devices; Acoustic microscopy; acoustic phenomena; Applied physics; Atomic force microscopy; Imaging; Imaging techniques; interdigital transducers; Microscopes; Microscopy; OTHER INSTRUMENTATION; phonons; Piezoelectricity; Raman microscopy; Raman spectroscopy; Standing waves; Stress analysis; stress measurement; Substrates; Surface acoustic wave devices; Surface acoustic waves; surface strains
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/5.0034572

Surface acoustic wave devices have been fabricated on a GaAs
100 substrate to demonstrate the capability of 2D Raman microscopy as an imaging technique for acoustic waves on the surface of a piezoelectric substrate. Surface acoustic waves are generated using a two-port interdigitated transducer platform, which is modified to produce surface standing waves. We have derived an analytical model to relate Raman peak broadening to the near-surface strain field of the GaAs surface produced by the surface acoustic waves. Atomic force microscopy is used to confirm the presence of a standing acoustic wave, resolving a total vertical displacement of 3 nm at the antinode of the standing wave. Stress calculations are performed for both imaging techniques and are in good agreement, demonstrating the potential of this Raman analysis.