Microwave ECR Plasma Enhanced Magnetron Sputtering Deposition Of AlN Thin Films

AlN thin films were prepared by MW-ECR plasma enhanced magnetron sputtering method with Al target and Ar/N2mixture gas. The influences of the deposition parameters on the AlN film’s chemical structure and properties were studied at room temperature and then the influences of the substrate temperature on the AlN films were studied. Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD), Ellipsometry micro-hardness tester were used to study the films structure and properties.When AlN films were prepared at room temperature, FT-IR indicates that short deposition time (10min and30min)lead more defect and low density, three hours deposition shows better chemical structure. The sputtering powers, gas flow ratio of N2and Ar both have influences on chemical structure, deposition rate and hardness of AlN films:With higher sputtering power and less N2flow rate, the deposition rate of AlN film is faster and hardness is higher. Higher sputtering power also causes less residual stress. AlN films were prepared with sputtering power of500W, N2flow rate of2SCCM as insulating films in cutting measurement temperature sensor. The insulation resistance of AlN films are far exceed the requirements.FT-IR results show that chemical structures of AlN films are different at different N2flow rate when the substrate was heated. When the N2flow was3SCCM, substrate heating caused impurities in the films, however when the N2flow was2SCCM, substrate heating lead stronger vibration of Al-N bond and less impurities as the substrate temperature increased. XRD indicates the formation of (100) preferred orientation of AlN film, and higher substrate temperature lead grain size increased. The refractive index of AlN films also increased when the substrate was heated.