Contact mode potentiometric measurements with an atomic force microscope on high resistive perovskite thin films

We have investigated the potential distribution on barium titanate thin films with an atomic force microscope in contact mode to find answers to the important question of local electric conductivity. A detailed knowledge about the electrical transport mechanisms is very important to receive a sound operation for highly integrated circuits such as non-volatile memory cells. With this paper we present an advanced method to perform these potential scans in galvanic contact. Key element of the set-up is an optimized electrometer amplifier which has an electronically reduced input capacitance avoiding the work function influence on the surface potential scan. To demonstrate the capability of our set-up we present example measurements performed on thermally reduced BaTiO3BaTiO3 thin films.