Fabrication of a quartz tuning-fork probe with a sharp tip for AFM systems

• Published in: Sensors and actuators. A. Physical. Vol. 148; no. 1; pp. 311 - 318
• Main Authors: Hida, H., Shikida, M., Fukuzawa, K., Murakami, S., Sato, Ke, Asaumi, K., Iriye, Y., Sato, Ka
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 04.11.2008
• Subjects: AFM; Anti-phase vibration mode; Crystal quartz; Q-factor; Tuning-fork; Crystal quartz; Q-factor; AFM; Anti-phase vibration mode; Tuning-fork
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2008.08.021

A quartz tuning-fork probe can oscillate and can be used to detect an atomic force between the tip and the sample surface due to the piezoelectric property of quartz. We have designed a tuning-fork structure with a large spring constant of 50 N/m to prevent probe adsorption to the sample surface. We developed a fabrication process to integrate the tuning-fork probe with the tip structure by applying two different processes: anisotropic wet etching and a focused ion beam (FIB) system. The length, thickness, and width of a beam of the fabricated tuning-fork were 1500 μm, 100 μm, and 100 μm, respectively. The height of the tip formed at the end of one beam was less than 6 μm. We also evaluated the self-oscillation properties of the fabricated quartz tuning-fork in two vibration modes – in-phase and anti-phase – and experimentally obtained a significantly improved quality ( Q) factor of 5247 in the anti-phase mode. The fabricated tuning-fork was able to detect a 100-nm-high step by using the self-oscillation property in tapping-mode atomic force microscopy (AFM).