Young's modulus measurement of a silicon nitride thin-film using an ultrasonically actuated microcantilever

The Young's modulus of a silicon nitride (Si3N4) thin-film was evaluated using an ultrasonically actuated microcantilever in the present study. The length, width, and thickness of the silicon microcantilever are 45 μm, 25 μm, and 1.78 μm, respectively. A 380 nm thick Si3N4 film was deposited on the microcantilever's surface using plasma enhanced chemical vapor deposition. The free vibration of the microcantilever was induced by an ultrasonic transducer and detected using a Michelson interferometer. Results show that the optical measurement successfully captured the vibration of the microcantilever, which made it possible to determine the Young's modulus of the Si3N4 film. The results were validated by nanoindentation testing and were found to be in good agreement within the error ranges. The present investigation proposes a novel method to evaluate the material properties of thin-films and nanoscale materials with enhanced sensitivity and detectability.