1E – Interferometric imaging of surface vibration fields in microacoustic devices: application to research and development of SAW, BAW and MEMS components

Title1E - Interferometric imaging of surface vibration fields in microacoustic devices: application to research and development of SAW, BAW and MEMS components
InstructorKimmo Kokkonen, Qorvo Munich GmbH
Overview of topics covered

  • Wave motion in acoustic wave devices

  • Principles of optical detection of surface vibrations

  • Basics of interferometric detection and optical setups

  • Application examples for SAW, BAW and MEMS: quasi-static to several GHz

  • Visualization of wave modes and wave confinement

  • Unwanted spurious resonances, radiation / losses

  • Wave slowness, plate wave dispersion
TimeMonday, October 22
8:00am-12:00am
RoomSapphire
AbstractThis short course is intended to introduce the participant to the possibilities offered by optical non-contact probing techniques for the characterization of surface vibration fields in a wide variety of microacoustic devices and test structures.
The covered optical measurement methods are applicable over a wide frequency range from semi-static deformation measurements, low-frequency MEMS resonators and transducer arrays to modern SAW and BAW devices with their resonance frequencies up to a few GHz.
The short course starts by providing a motivation for the optical probing of surface vibrations. This is followed by an overview of optical techniques that enable non-contact measurement of the surface vibration fields. After the general overview, we will focus on interferometric techniques. This part will include an introduction to the interferometric measurement principle, typical optical setup, the detection equations, and the hardware needed for the measurement of both the amplitude and phase of the surface vibration.
The second part of the course illustrates the capabilities of optical probing through a
set of application examples. These will include topics such as measuring the plate wave dispersion properties of BAW resonators, investigating wave behavior and energy losses in SAW devices, and studying the vibration modes and non-linear behavior of MEMS resonators.
Short CV of Instructor Dr. Kimmo Kokkonen was born in Helsinki, Finland, in 1977. He received his M.Sc. (Tech.) degree at Helsinki University of Technology (TKK), Finland. During his studies he worked as a research scientist in the Materials Physics Laboratory at TKK. He received his D.Sc. (Tech.)at the Department of Applied Physics, Aalto University School of Science, Finland.
He has published over 25 peer-reviewed journal articles and numerous conference papers on optical non-contact measurement of surface vibrations, wave propagation and behavior in microacoustic devices and on device physics. After leading the microacoustics research team at the university for several years, Dr. Kokkonen joined Qorvo Munich GmbH in 2015 as a Senior R&D Acoustic Device Engineer.