Evaluation of AlN material properties through vibration analysis of thin membranes

Abstract

In this work, the mechanical properties of thin piezoelectric AlN films along with the methods and instruments to obtain this information with sufficient accuracy via dynamic (vibration) and static analyses of thin membranes are reported. In addition, the impact of different damping mechanisms on the amplitude of forced oscillations have been considered in order to obtain the analytical expression relating the resonant amplitude of membrane to the ambient gas pressure

Static and dynamic characterization of AlN and nanocrystalline diamond membranes

“…The approximated values for the 200 nm thick NCD membranes of E ∼ 852 GPa as well as for the 400 nm thick AlN/NCD membrane of E ∼ 492 GPa have been derived. The derived values for the 220 nm thick AlN membranes are σ ∼ +390 ± 13 MPa and E ∼ 374 ± 11 GPa 42, which is in good agreement with the literature (cf. Table 1).…”

“… (online color at: http://www.pss-a.com/) Pressure load curves of (a) compressively stressed 200 nm thick NCD and 400 nm thick AlN/NCD unimorph structures, and (b) tensile stressed 220 nm thick AlN membranes 42. The Young's moduli have been derived using Eq.…”

“… (online color at: http://www.pss-a.com/) Log–log plot of experimental resonant frequencies versus membrane diameter (black rectangles), fitted by the dashed lines given by Eq. (5) 42. Examples of some mode shapes measured by LDV are shown in the right part of the figure.…”

“…A method that allows a more local determination of the residual stress and also of the Young's modulus is given by bulge experiments of thin membranes. It has been used for AlN 42 as well as NCD membranes 6, 33. In these studies, N 2 gas was used to induce an overpressure at the backside of the membrane of radius R .…”

Online Test Structure for Measuring Young’s Modulus and Residual Stress of the Top Silicon Layer of Silicon-On-Insulator by a Pull-in Approach

“…For thin films, the key material properties, e.g., Young's modulus and the residual stress σ, are very sensitive to the fabrication method. (1) The application of thin films depends on their mechanical properties to a large extent. (2) To provide information regarding material parameters for MEMS engineers both for design and optimization, it is nesseary to extract material properties for a given process.…”