Electrical AFM Modes

Electrical Measurement Modes

AFM can probe a wide variety of electrical properties of materials and surfaces. These methods operate either in static mode or dynamic mode, depending on the information being sought. Probing properties such as current, conductance, surface potential, and capacitance are increasingly important in a number of applications including research on semiconductors, solar and battery cells, conductive polymers, and nanoelectronics. These applications have in common that the electrical properties of increasingly miniaturized devices and features need to be measured. Note that all these methods require specialized tips, usually in the form of a conventional silicon AFM cantilever coated with an electrically conductive coating. Probes made of conducting diamond are also suitable for some of these methods. All these modes provide simultaneous topography and electrical property data. A review of some of the main electrical modes and properties are given here.

These electrical modes also often take advantage of interlaced and dual pass scan methods, in which the probe measures topography on the forward or first pass and then the probe is lifted a prescribed distance away from the surface on the backward or second pass, optionally following the topography (contour) of the sample, as shown in the section on advanced scanning methods.