Growth and Characterization of AIN thin films on free-standing diamond substrates

The free-standing diamond films with a smooth and high quality nucleation side were prepared by hot filament chemical vapor deposition (HFCVD) method. The nucleation side of the films had a mean surface roughness of 1.6nm.AIN films were then deposited on the nucleation side of the above diamond films by radio-frequency (RF) reactive magnetron sputtering method. The structure characteristics of AIN films deposited under different working pressure (p), sputtering power (w) and sputtering plasma composition were studied. The optimized parameters for the growth of high c-axis orientation AIN films were obtained: p=0.2Pa,w=600w and Ar/N-2=3:1.Surface morphologies of AIN films deposited under these parameter jested by means of atomic force microscope (AFM),showed that the mean surface roughness was about 4.lnm.It also had a strong c-axis orientation structure investigated by X-ray diffraction (XRD).All results above suggested that the AIN/diamond structure prepared in this work was ideal for the application of high frequency surface acoustic wave devices (SAW) device.