Kelvin Force Microscopy Characterization of Corona Charged Dielectric Surfaces

The corona-Kelvin based technique has been used asa non-contact, preparation free replacement of MOSand Schottky barrier capacitancevoltage (CV) measurements. It allows quantication of dielectric and interface properties such as dielectric capacitance and electrical thickness [14], density of interface states [24], andleakage across the dielectric [26]. Traditionally, a largespot corona-Kelvin approach is applied to unpatternedmonitor wafers with blanket dielectric layers [2, 4, 5].A miniaturization of both the Kelvin probe and coronadeposition area has been introduced that extended thecorona-Kelvin metrology to small spot measurements onproduct (i.e. patterned) silicon IC wafers and specicallyto scribe-line test sites, which are 100 µm × 100 µm orsmaller [4, 7]. Modied Kelvin force microscopy (KFM)with a probe of about 10 µm is used for surface potential measurements while the corona deposition diameteris reduced below 100 µm by employing a small aperturecorona gun with electrostatic ion focusing [7].