Static and dynamic characterization of AlN and nanocrystalline diamond membranes

Abstract

In this work, AlN and nanocrystalline diamond thin films as well as multi-layer structures on their basis are characterized towards their mechanical properties. In particular, the Young's modulus E and the residual stress s are obtained by wafer bow measurements of thin films as well as by bulge experiments and vibration measurements of freestanding membranes. Depending on the growth conditions, the AlN thin films, deposited by reactive magnetron sputtering, revealed values of s $ þ300 up to þ400 MPa and E $ 370 GPa, while the diamond films, grown by microwave plasma CVD, showed values of s $ À60 to þ60 MPa and E $ 870 up to 1000 GPa. The values and the accuracy of the characterization techniques used are discussed and their limits are demonstrated.

Modeling and characterization of piezoelectric beams based on an aluminum nitride thin‐film layer

“…Luo's theory gives more homogeneous values around 200 MPa. This stress value is close to the stress range from 300 to 400 MPa given by Knöbber et al obtained by wafer bow of the AlN thin films, deposited by reactive magnetron sputtering. A summary of these results is presented in Table .…”

“…Residual stress and Young's modulus in thin films are important to match the mechanical frequency and reliability of MEMS . Various methods have been published to extract Young's modulus, such as the resonance‐frequency method and nanoindentation . Residual stress measurements in thin‐film layers such as dielectric films are more common and many techniques are available .…”

Mechanical properties and reliability of aluminum nitride thin films

“…In comparison, the bulge test method [27,30] is simpler and does not suffer from the same drawbacks. This method requires no careful alignment of the measurement setup and the throughput of the sample fabrication process is considerably better.…”

Ultrasonic and Spectroscopic Techniques for the Measurement of the Elastic Properties of Nanoscale Materials

“…Interestingly, for membranes which become nanometric but have significantly larger lateral extension, the continuum approach remains useful, both for the theoretical analysis and the measurement technique. Membranes of nanocrystalline diamond and of piezoelectric aluminum nitride, and bilayer membranes, with thicknesses down to 220 nm and diameters up to 1 mm, have been investigated by Knoebber et al [29] by both a static and a vibrational technique. The static technique, of more macroscopic character, was the bulge test, in which the deflection of the circular clamped membrane under gas pressure is measured; the implementation was optical, the deflection being optically measured by white light interferometry.…”