Thickness dependence of the properties of highly c-axis textured AlN thin films

The influence of film thickness on the material properties of aluminum nitride (AlN) thin films deposited on Pt(111) electrodes has been investigated experimentally by means of x-ray diffraction, dielectric response, atomic force microscopy, interferometry measurement of effective $d33,$ and residual stress measurement. The thickness was varied between 35 nm and 2 μm. Full width at mid-height of the rocking curve decreased from 2.60 to 1.14°, rms roughness increased from 3.8 to 18.6 Å, the effective $d33,$ namely $d33,f,$ from 2.75 to 5.15 pm/V. The permittivity $εAlN$ was stable at 10.2, whereas the dielectric losses decreased from 1% to 0.1%. The breakdown electric field under dc voltages varied between 4.0 and 5.5 MV/cm.