Surface voltage and surface photovoltage: history, theory and applications

Surface voltage and surface photovoltage measurements have become important semiconductor characterization tools, largely because of the availability of commercial equipment and the contactless nature of the measurements. The range of the basic technique has been expanded through the addition of corona charge. The combination of surface charge and illumination allows surface voltage, surface barrier height, flatband voltage, oxide thickness, oxide charge density, interface trap density, mobile charge density, oxide integrity, minority carrier diffusion length, generation lifetime, recombination lifetime and doping density to be determined. In this review I shall briefly review the history of surface voltage, then discuss the principles of the technique and give some examples and applications.