Contactless scanner for photoactive materials using laser-induced microwave absorption

Conventional laser scanning techniques for the topological characterization of photoactive materials and devices are hampered by the need to apply electrical contacts. We present a technique to overcome this limitation using the relative change of reflected microwave power to probe the conductivity locally induced in the sample. After a discussion of the theoretical background and the limitations of the method the apparatus is described. Application to scan the surface of a semiconductor chip carrying an electrode structure is used to discuss the resolution and linearity.