New Method for Evaluating Intrinsic Mechanical Q Factor of SCALN, GAN, Metal Films by GHz Ultrasonic Pulse-Echo Technique

This paper reports a novel method for evaluating <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q_{\mathrm{m}}$</tex> factor of film materials using the pulse-echo technique. This method enables the evaluation of the intrinsic <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q_{\mathrm{m}}$</tex> of piezoelectric films or other films such as metal electrode films, requiring no optimization of the BAW resonator geometry compared to a conventional resonator method. This study investigates the relationship between grain size and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q_{\mathrm{m}}$</tex> using the proposed method.