Analysis And Fabrication Of AlN/Diamond Multilayered Structure High Property SAW Device

Surface acoustic wave devices (SAWD) have perfect character of high reliability,minicapacity,mutiple function and have being used widely in the scope of radar,sonar,wireless communication,optics communication,broadcast system. In recent years, there has been an increasing interest in developing surface acoustic wave devices operating at high frequencies. In order to obtain high-frequency SAW devices, a substrate material with high acoustic velocity is desired. By depositing a piezoelectric film on top of a substrate diamond, the high frequency can be achieved without the fabrication fine of IDT.Diamond substrate is an attractive material because of its high acoustic velocity. And AlN thin film has been widely used for layered SAW devices due to its high piezoelectric character. Therefore, IDT/AlN/diamond which is a promising multilayered structure for high-frequency SAW device is analysis and fabricated. The growth of thin films was simulated. The processes of particle deposition, adatom diffusion were taken into account in our model. The results show that the films growth undergoes disperse, fractal and conglobating, with the increase of particles migrating steps by increase the temperature.We have deposited the diamond films whose satisfied to SAW filter using chemical vapor deposition (CVD) reactor were investigated. The piezoelectric AlN layer is fabricated on diamond and silicon substrates using RF magnetron sputtering, and the sputtering parameters have been extensively investigated here.Substrate heater temperature, sputtering gas pressure are the most important factors to determine the quality of AlN thin film. After these parameters have been properly set, grown AlN layer shows highly oriented, dense and fine-grain, excellent surface flatness and high resistivity. AlN thin films have been characterized by XRD, SEM, AFM.In this thesis, deposition parameters such as working pressure, sputtering power, substrate temperature, and deposition time have been studied, and orientation growth law for AlN thin films has been obtained. lower working pressure, Higher sputtering power,Higher substrate temperature and longer deposition time are favor of growing AlN thin films with (002) oriented, in verse, with (100) oriented.The innovation research results of this paper are following:1. Research theory of thin films growth, program about simulation.2. AlN/diamond multilayered structures SAWF are fabricated in this thesis.