in-situ röntgendiffraktion zur charakterisierung von mechanischen ...

possibility to determine experimental XEC without using any special diffractometer
attachments and without delicate sample preparation.
To extend the possibility of X-ray substrate curvature measurements to high temperatures, a
heating chamber was developed, enabling free bending of specimen for different
temperatures. Using this newly developed heating chamber, first measurements of
temperature dependent X-ray substrate curvature could be performed successfully. The
functionality is demonstrated on Al-, TiN- and Cr thin films in the temperature range of
room temperature up to 400°C. The results show an accuracy of 10% of the stress values,
what is comparable to commonly used laser assisted substrate curvature systems.
Moreover, first feasibility studies were performed in order to use the heating chamber for
measuring temperature dependent XEC by the combination-method. The results show that it
is possible to determine temperature dependent XEC, but the sample fixing system in the
current heating chamber has to be modified to increase the accuracy of the results.
In a further study, size and temperature dependencies of thermal strains of (111) textured Al
thin films were determined by in-situ X-ray diffraction in the temperature range of -100°C to
350°C. The experiments were performed on 50nm to 2000nm thick Al films on oxidised Si
substrates. The obtained stress-temperature evolutions show the well known increase of flow
stresses with decreasing film thickness for films thicker than 400nm, while thinner films
reveal a stress plateau. With decreasing minimum temperature of the thermal cycle, the
stress values increase. Even at -100°C the stresses remain independent of the film thickness
in the plateau region. The observed stresses are discussed taking micro-structural
information and possible deformation mechanism into account. For the characterisation of
the film microstructure, different microscope techniques were used. TEM studies were
performed to obtain information about possible dislocation processes, SEM characterisations
were used to find deformations by hillock formation, and AFM measurements were carried
out to observe a possible stress relaxation via the surface.