The characterisation of ferroelectric thin films using nanoindentation

Nanoindentation techniques have been used to determine the mechanical prope rties of two well characterised Pb0.88La0.08TiO3 ferroelectric thin films w hich have been shown to be promising for MEMs applications. A ceramic with the same nominal composition and the substrate material were also tested as an aid in the interpretation of results. Test routines have been developed using the spherical indentation geometry to distinguish the elastic and pe rmanent deformation of the materials. Mechanical data for different layers in the heterostructure could be determined by using indenters with differen t radii. The technique provides information on the elastic modulus of the f ilm, the onset and nature of permanent deformation, film delamination and t he effects of porosity and residual stress. These techniques open the possi bility to characterise fully the mechanical response of a microdevice.