Surface voltage and surface photovoltage measurements have become important semiconductor characterization techniques, largely because of their contactless nature and the availability of commercial equipment. The use of these contactless measurement techniques has broadened from initial application of minority carrier diffusion length measurements to a wide variety of semiconductor characterization, including surface voltage, surface barrier height, flatband voltage, oxide thickness, oxide charge density, interface trap density, mobile charge density, oxide integrity, generation lifetime, recombination lifetime and doping density. It is likely that this range of applications will broaden further. As with all characterization techniques, there are limitations but they are frequently compensated by the contactless nature of the measurement thereby simplifying test structure fabrication.
