A sensitive method for measuring surface conductivity of insulators

Abstract
A method is described for measuring the surface conductivity of insulating thin films. The conductivity is determined by observing the current transients while charging a capacitor whose dielectric is the insulating material and part of whose top electrode is the insulator surface. No elaborate sample preparation or experimental apparatus is required. Results are presented for oxide thermally grown on silicon, where sheet resistances between 1016 and 1020 Ω/⧠ were obtained for different values of relative humidity. The method can also be applied to a thin conducting layer on top of a thicker insulating film.