NOVEL MILLIMETER-WAVE NEAR-FIELD RESISTIVITY MICROSCOPE

We demonstrate a technique for contactless mapping of resistivity or d ielectric constant of surfaces and films with a spatial resolution bet ter than 100 mu m. This technique may be used for the nondestructive t esting of semiconducting wafers, conducting polymers, oxide supercondu ctors, and printed circuits. The principle of operation consists of th e scanning of a tiny millimeter-wave antenna at a very small height ab ove an inhomogeneous conducting surface and measuring the intensity an d phase of the reflected (transmitted) wave. We use a specially design ed resonant slit antenna and achieve subwavelength spatial resolution of lambda/50. (C) 1996 American Institute of Physics.