Kelvin probe force microscopy for material characterization

Kelvin probe force microscopy is a scanning probe method for imaging the surface potential by atomic force microscopy. The surface potential is one of the most important surface properties and is correlated to e.g. the work function, surface dipoles, localized surface charges and structural properties. It gives detailed information on the electrical properties and can be combined with optical and electrical excitation mechanisms providing additional properties like surface band bending and charge carrier mobilities. We will introduce the main concept and will briefly describe the major methods of operation. Based on the analysis of a Si superjunction device, structures dopant profiling and the concept of surface photovoltage measurements will be introduced. The influence of local charge accumulation on these devices will be presented and the effect on the measured contact potential values will be discussed.