Characterisation of piezoelectric ZnO cantilever for applications in hard disk drives

• Main Author: Chia, Xin Fang.
• Other Authors: Du Hejun
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Microelectromechanical systems; DRNTU::Engineering::Materials::Material testing and characterization
• Online Access: http://hdl.handle.net/10356/49528
• Institution: Nanyang Technological University

The application of piezoelectric materials in Micro-electro-mechanical systems (MEMS) are growing with the increasing need for miniaturization and advancement in technology. Its ability to act as a sensor and operate without conditioning circuits, coupled with the advantage of being miniscule, lightweight and easy to use, makes it a natural subject for research in further development. For this project, a piezoelectric ZnO thin film fabricated on a cantilever through RF magnetron sputtering was characterized to find out its capability of sensing and actuation, and potential applications on head sliders in hard disk drives. The current trend of improving recording densities in hard disk drives requires the head slider to exhibit high-frequency positioning close to 10 nm or less. Three different characterization tests were employed to find the resonant frequency, actuating sensitivity and sensing sensitivity of the ZnO cantilever. First, the resonant frequency was obtained through impedance testing and frequency response function. Resonance of the cantilever is at 53 kHz with working bandwidth of 27 kHz. Second, vibration experiments using a Laser Doppler Vibrometer (LDV) were conducted. Analysis of the results showed that the actuating sensitivity was 10 nm/V at 15 kHz. Third, shaker testing using accelerometer was performed to investigate the sensing sensitivity of the cantilever. The sensing sensitivity at 15 kHz was found to be 1V/ms-2. The performance of the ZnO thin film was concluded to be suitable for use on head sliders, as both the actuating and sensing sensitivities observed through characterization were rather significant, implying ease of application.