Voltage contrast XPS—a novel scheme for spatially resolved XPS studies

A novel scheme is introduced which allows spatially resolved XPS studies to be performed in device applications by taking advantage of the ability to bias the various components of the device. The application of a bias voltage produces a shift in the Fermi level of the biased component and there is a corresponding shift in the binding energy of electrons emitted from this component. In this manner it is possible to discriminate between the XPS signals due to a given element but which originate from different areas of the sample. By analogy with the corresponding biasing scheme employed in SEM studies, this technique has been called Voltage Contrast XPS. To illustrate the capabilities of this technique an application involving a recently proposed integrated thermionic emission device is presented. Copyright © 1987 John Wiley & Sons Ltd.