[Zurück]

A. Ababneh, G. Marchand, H. Seidel, J. Hernando-Garcia, J.L. Sànchez-Rojas, Ü. Sökmen, E. Peiner, U. Schmid:
"Comparison Between AlN Thin Films with Different Crystal Orientation for MEMS Applications";
Vortrag: SPIE Europe: Microtechnologies for the New Millennium, Dresden, Deutschland; 04.05.2009 - 08.05.2009; in: "Proceedings of SPIE", Society of Photo-Optical Instrumentation Engineers (SPIE), 7362-7366 (2009).

Aluminium nitride (AlN) reactively sputter deposited from an aluminium target is an interesting compound material due to its CMOS compatible fabrication process and its piezoelectric properties. The crystal structure obtained during sputtering is a very importance criterion to obtain a good piezoelectric performance. To demonstrate this, we focused our investigations on two types of films. The first type shows a good c- axis orientation with round grain geometry. The
second type is (101) oriented having a triangular grain shape. For measuring the out-of-plane displacements for dij determination, a MSV 400 Polytec scanning laser Doppler vibrometer was used. To obtain the piezoelectric constants d33 and d31 a fitting procedure between experimental and theoretical predicted results is used. Effective values for d33 and d31 in c-axis oriented films are about 3.0 pm/V and -1.0 pm/V, respectively. By contrast, films with (101) orientation show a lower effective longitudinal piezoelectric coefficients, consistent with this different orientation.
Finally, both types of AlN layers were deposited on 640 μm long micro-cantilevers. The average displacement of the first mode on the vertical axis was about 12 nm for the film with good c -axis orientation and 0.3 nm for that with (101)-orientation when applying the same excitation.

Aluminium nitride, thin film, crystal structure, piezoelectric constant, micro-cantilever

http://dx.doi.org/10.1117/12.821858