Surface Acoustic Wave Properties of AlN Films Deposited on SiO2/Si Substrates

• Main Authors: Lai, Erh-Kun, 賴二琨
• Other Authors: Chen, Ying-Chung
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/44652916710972724812

碩士 === 國立中山大學 === 電機工程研究所 === 85 === The surface acoustic wave (SAW) devices play an important role for communication system and signal processing. In this thesis, we tried to deposit highly c-axis oriented AIN films with smooth surfaces, good adhesion and strong piezoelectricity on SiO2/Si substrates by reactive RF magnetron sputtering. The dependence of crystallization and surface morphology were investigated by varying the sputtering conditons such as sputtering pressure, nitrogen concentration (N2/N2+Ar), and RF power. Then the interdigital transducers (IDTs) were fabricated on the films to estimate the surface acoustic wave properties using AIN thin films. The XRD and SEM results showed that the structural characteristics and surface morphology were found to be sensitive to the deposition parameters. The best conditions to deposit highly c-axis oriented AIN thin films were the nitrogen concentration of 75%, RF power of 300W, and sputtering pressure of 7.5~15 mTorr. The dielectric constant and resistivity of the obtained highly c-oriented AIN thin films were measured of about 9.46 and 1.06×1011 Ω-cm, respectively. Besides, Double finger interdigital transducers with wavelength 32μm were fabricated on the AIN thin films. The center frequency, insertion loss and phase velocity of SAW were measured of about 190MHz, -24.8dB and 6080m/sec, respectively.