Piezoelectric properties of thin AlN layers for MEMS application determined by piezoresponse force microscopy

Abstract Piezoelectric properties of aluminium nitride thin films were measured using both, the piezoresponse force microscopy and an interferometric technique. Wurtzite AlN thin films were prepared on Si (111) substrates by reactive DC‐sputtering and by metalorganic chemical vapor deposition. Direct measurements of the inverse piezoelectric effect in the picometer range showed that the acceptable tolerance in the crystal orientation is much larger for MEMS applications than expected previously. The value of the piezoelectric coefficient d33for the prepared AlN thin films was determined to be 5.36 ± 0.25 pm/V for highly textured as well as for polycrystalline thin films with a (002) preferential orientation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)