Contact free potential mapping by vibrating capacitor
The contact free vibrating capacitor method is a valuable tool for investigating the surface potentials of solid surfaces. The purpose of the present article is to summarize the theory and capabilities of the vibrating capacitor method, especially scanning vibrating capacitor pictures in the electronics. After a brief review some results will be discussed, such as a contact potential map taken from a printed circuit board, a surface potential map from a biased ceramic thick film circuit and some results from silicon solid state devices and solar cells. Potential maps contain a lot of information concerning the surface conditions, included the inhomogeneities of the technology, bias and other additional excitation. These potential maps may help in the development, quality control and defect analysis
Surface potential mapping: comparison of the vibrating capacitor and the SPV method
Abstract Surface potential maps are very important for characterisation of insulator covered and bare semiconductor surfaces. Contactless methods use capacitive coupling. Vibration (vibrating capacitor) and light (SPV, surface photo voltage method) are used for the surface excitation. Both methods give information about the surface potential, and are sensitive to the surface charge, too. This article discusses the differences and similarities between the methods, concerning theory, application and evaluation of the results. Several surface potential maps are presented and evaluated too.
Laser surface photovoltage spectroscopy: A new tool for the determination of surface state distributions
A new experimental technique, which utilizes a tunable laser as the illumination source for surface photovoltage spectroscopy measurements, is presented. The data obtained by this technique make it possible to determine the distribution function of gap states observed at semiconductor interfaces. An outline of the approach together with experimental results obtained using a Ti:sapphire laser on InAlAs and CdTe crystals is given.