Work function spectroscopy as a tool for thin film analysis

Abstract

Work function measurements are known to provide important information on the structural and chemical conditions of surfaces and interfaces. Lateral and depth-dependent variations in the work function can be determined in an electron beam scanning mode by measuring locally the onset energy of the secondary electron energy distributions, e.g. in a scanning Auger microprobe. Corresponding studies have been performed for a polycrystalline aluminium surface and an NiCr multilayer system. The potentialities of work function scanning microscopy as a novel analytical technique are demonstrated by resolving the structure of small impurity particles in thin sublayers. Although work function spectroscopy does not provide direct chemical information, it has proved to be a very useful technique especially in conjunction with scanning Auger or scanning electron microscopy.