Scanning Near Field Acoustic Microscopes for the Evaluation of Polycrystalline Materials

Analysis of functional inorganic ceramics necessitates techniques enabling a detailed knowledge of thermal, mechanical, and — if applied for electrical engineering — electronic features. Due to the typical size of material-relevant structures the spatial resolution has to be clearly beyond a micrometer, in difficult cases even in the lower nanometer region. Whereas conventional acoustic microscopes lack sufficient resolution, so-called scanning near-field acoustic microscopes can overcome the situation. In general, any microscope system can be understood in this manner that uses the impact or generation of sound in or at the direct vicinity of the sample surface with an interaction volume being much smaller in size than the wavelength of the acoustic signal used for the detection of the material properties. Techniques in this respect are photo, electron1, and ion acoustic microscopes as well as just recently probe acoustic microscopes2.