The Measurement of Silicide Schottky Barrier Heights by Use of Photovoltaic Techniques

Abstract

ABSTRACTSchottky barrier structures often exhibit forward bias current voltage characteristics possessing a marked deviation from ideal behavior. In many cases, this deviation can be attributed to the influence of an appreciable series resistance on the diode characteristic making the determination of the actual Schottky barrier height from this characteristic difficult. In a study of rare earth silicides on Si, the present authors have successfully employed an alternative technique which overcomes this series resistance effect. This technique is derived from the conventional methods for obtaining barrier height and series resistance values in photovoltaic devices, although not necessarily requiring transparent metallizations. Photogenerated current from the device periphery is utilized here in the determination of the barrier height. The measurement of both open circuit voltage and the short circuit current at varying illumination intensities allows the junction characteristic to be determined essentially free from series resistance effects. A comparison will be made between the values of the barrier height derived from conventional J-V and photoresponse measurements, with photovoltaic measurements made on structures possessing either a semi-transparent or opaque metallization.