Measurement of the steady−state potential difference across a thin insulating film in a corona discharge

Abstract

A comparison method has been developed for measurement of the potential difference across a thin insulating film under steady−state charging conditions in a corona discharge. The method is based on the dynamics of charged particles (ions or electrons) when drifting under collision−dominated conditions: their trajectories follow, to a close approximation, the electrostatic field lines. The method is simple, accurate, and reliable, and it is particularly valuable where the surface potential, following cessation of charging, decays too rapidly to permit use of the conventional Kelvin probe techniques. The method has been applied successfully to the study of the electrical behavior of thermally grown SiO₂ films on Si and thermoplastic materials.