The Deposition And Research Of AlN (100) For High-Frequency Saw Devices

SAW devices have the advantages of the small scale, high frequency ,large bandwidthand real-time signal processing. With the rapid development of microelectronics,telecommunications and other fields, there is increasingly high demand for high-frequencyand high-performance SAW devices. If we want to prepare high-frequency and high-powerSAW devices, we must study the piezoelectric thin film materials for the first. AlN hasexcellent physical and chemical properties for high-frequency surface acoustic wave devices.therefore, the preparation and the study for the piezoelectric properties of AlN thin films arevery important.AlN thin films with (100) preferential orientation were prepared by radio frequency (R.F.)magnetron sputtering technique.The structure properties of the film were analysised by XRD.The influence of gas pressure and sputtering power on the properties of (100) oriented AlNfilm were studied. The surface topography and the piezoelectric properties of the film wereanalysised by PFM.. The main contents are as follows:(1) AlN thin films with (100) preferential orientation were prepared on Si(100) substrate(including Au conductive layer) by radio frequency (R.F.) magnetron sputtering technique.(2) The influence of gas pressure on the properties of (100) oriented AlN film werestudied.The results show that，(100) oriented AlN film was easily formed at higher gaspressure.(3) The influence of sputtering power on the properties of (100) oriented AlN film werestudied.The results show that，(100) oriented AlN film was easily formed at lower sputteringpower.(4) From the PFM texting, we know that the piezoelectric properties of the (100)oriented AlN film is mainly reflected in the inner area of the film.For the AlN,c-axis is thepolar axis.When we give the mechanical force along this direction,the strongest electriccharge is produced. When we give the mechanical force along a-axis which is perpendicularto the polar axis, there is no electric charge on the (100) surface but some electric charge onthe (002) surface.