Measurement of the effective piezoelectric constant of nitride thin films and heterostructures using scanning force microscopy

Contributors:   B.J. Rodriguez, D.-J. Kim, A.I. Kingon, and Robert J. Nemanich

ABSTRACT

Piezoelectric properties of wurtzite AlN and GaN/AlN are investigated using scanning force microscopy (SFM). The magnitude of the effective longitudinal piezoelectric constant d33 of AlN and GaN/AlN thin films are measured and reported, and the d33 coefficients of these films were verified using an interferometric technique. Simultaneous imaging of the topography, and of the phase and magnitude of the piezoelectric strain is performed. Using a GaN film with patterned polarities, we demonstrate that polarity can be inferred from the phase image of the piezoelectric strain. We report d33=3±1 pm/V for AlN/SiC and 2±1 pm/V for GaN/AlN/SiC. Films grown by organo-metallic vapor phase epitaxy (OMVPE) on SiC, sputtered AlN films and films grown by molecular beam epitaxy (MBE) are characterized and compared.

Publisher: Materials Research Society Symposium Proceedings,   Volume: 693,   571-576 ||  Published: 2001-11 ||   Read more...