Authors: R.E. Sah, L. Kirste, M. Baeumler, P. Hiesinger, V. Cimalla, V. Lebedev, H. Baumann
Affilation: Fraunhofer Institute for Applied Solid State Physics, Germany
Pages: 344 - 347
Keywords: stress analysis, AlN films, piezoeslectric MEMS, actuating devices
Wurtzite type AlN thin films have recently become of great interest in microelectromechanical system (MEMS) and nanoelectromechanical system (NEMS) for sensing applications such as chemical and biological sensing, electrometry, and scanning probe techniques. As-grown films always have a residual stress. The magnitude and direction (tensile or compressive) of the residual stress vary depending on the deposition conditions. For most applications, the residual stress has to be minimized because it alters the energy band structures and the bending in MEMS. It can also influence the film properties, hence, the properties of devices. On the other hand, some devices, such as resonant strain sensors, require residual tensile stress for proper operation. Thus, in order to achieve desired properties for MEMS/NEMS, and for the reliability of these devices, an investigation of the residual stress and its stability is important. In our contribution, we will present our results of investigation on stress stability during aging and thermal cycling.