The Research Of Deposition And Structural Properties Of "AIN/Silicon" "AIN/Diamond" Multilayerd Films For SAW Device

In recent years, the rapid development of mobile communication, making radio communication frequency band into a limited and valuable natural resources. Therefore, they require a greater width of the wireless spectrum and to the high-frequency direction. High-frequency characteristics of SAW devices has been the concern of researchers in the country. As the piezoelectric material the advantage of aluminum nitride film is the fastest speed of sound in all inorganic non-ferrous electrical properties of piezoelectric materials. Aluminum nitride thus become a high-frequency SAW and body wave in the material of choice.In this study, AlN thin films have been deposited on Si. The emphasized influence of sputtering pressure, substrate temperature, sputtering power and other parameters is in order to further optimizing the deposition parameters of a high c-oriented AlN thin film. The film's surface morphology and composition have been detected and analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray scattering spectroscopy (EDS).The main results are shown below.(1)AlN films were fabricated at different sputtering powers and the other experimental parameters were the same. Along with the increasing of sputtering powers, the intensity of AlN XRD peak becomes notably better. But, when the sputtering power is too large, Al target will be dissolved and polluted which will be charred and black.(2)Sputtering pressure is a important experimental parameters, too low sputtering pressure and concentration of gas molecules will affect the glow discharge. The energy of particles reduces and the collision between particles becomes more acutely when the sputtering pressure is too high. In this study when the pressure is 0.5 Pa, (002) sharp X-ray diffraction peak showed in the result.(3)Atomic activity is low because of the low temperature. And the diffused atoms on growth surface increase because of the high substrate temperature, which improves the crystallization process.(4)The influence of N2 percentage on preferentially orientated AlN (002) thin film was studied. The experimental results showed that the films on Si (100) with 40% N2 exhibit good crystal properties with sharp X-ray diffraction peaks.(5)In this papers the influence of substrate orientation on preferentially orientated AlN (002) thin film was studied. The lattice mismatch were calculated, and the results shows that Si (100) plane and AlN (002) plane can be considered lattice fully-coherent.