Measurements of thin film properties are difficult when compared to bulk materials. One method for finding the modulus of elasticity of a thin film is from frequency analysis of a cantilever beam. A straight, horizontal cantilever beam under a vertical load will deform into a curve. When this force is removed, the beam will return to its original shape; however, its inertia will keep the beam in motion. Thus, the beam will vibrate at its characteristic frequencies. If a thin film is sputtered onto the beam, the flexural rigidity will be altered. This change causes the frequency of vibrations to shift. If the frequency shift is measured, the film’s elastic modulus can be calculated.
Due to the small size of thin films, conventional methods of measuring their properties often do not work. These thin film properties may differ from the bulk material properties. Therefore, alternative measurement methods must be developed. Vibration of cantilever beams is one of these methods. It is not limited to just determining the modulus of elasticity; other useful information, such as piezoelectric constants, can be determined from cantilever beams.