AFM probes

The primary goal is to develop a technology for versatile shapes of tips integrated with AFM cantilevers, so-called passive probes with external read-out. For this we have developed a process sequence for direct tips, where tips are obtained by etching the surrounding material, and a process sequence for indirect tips, formed by electroplating in etched holes, where the substrate is subsequently etched. In the direct method we have developed a novel tip shape, which we have named rocket-tips¿. The different tip shapes integrated with cantilevers have been demonstrated on several test samples. The second goal is to develop a demonstrator active probe, i.e. with integrated read-out, for a wide range of applications. After comparing different transduction principles we have chosen for piezoresistive read-out, using single-crystalline silicon piezoresistors on oxide. Modelling has yielded a design for optimum signal-to-noise ratio. A process sequence has been developed. A demonstrator is now under construction.
For ultrahigh-vacuum applications an AFM probe with capacitive read-out is under development. The fabrication technology is based on electroplating in anisotropically etched cavities in silicon.