The preparation of nanometer aluminum nitrogen(AlN) films with uniform lattice arrangement is of great significance for the manufacture of high-frequency surface acoustic wave(SAW) device.We put forward the two-step growth method and the annealing treatment method for the deposition of(100) AlN thin films.The results show that when the sputtering pressure is 1.2 Pa and the ratio between N2 and Ar is 12:8,the influence of lattice thermal mismatch and anti-phase is the smallest during the nucleation growth at low-temperature stage of(100) AlN/(100) Si films.The root-mean-square(RMS) surface roughness of AlN prepared by the two-step method is reduced from 6.4 nm to 2.1 nm compared with that by common deposition process.
Diamond films are deposited on porous Ti substrates by hot filament chemical vapor deposition (HFCVD) method. For adjusting the residual stress of substrate and the titanium carbide (TiC) intermediate layer, the substrates are under annealing process firstly, then are put into alkaline solution with electricity oxidation, and finally composite membranes are obtained by HFCVD, which are characterized by X-ray diffraction (XRD), metalloscope and scanning electron microscope (SEM). Results show that the composite membranes deposited on unannealed substrates are cracked obviously in both sides and broken off easily. After annealing process, the membranes are no longer cracked easily, because the tensile stress distributed in substrates is significantly relieved. After passivation process, TiC generated between diamond film and substrate is less than that without passivation process.
