Sheet Resistance Evaluation of Conductive Thin Films Using Microstrip Antenna

This paper presents a microstrip antenna based sensor for non-contact sheet resistance evaluation of conductive nano films. The film under evaluation, working as a radiation patch, is placed on top of a microstrip line. Through full-wave simulations, it was found that S11 at the input port of the microstrip line could be related to the sheet resistance of the conductive film. Both of the resonant frequency and loaded Q factor could be used as an indicator of electrical properties of thin film. Experiments were performed as a proof of concept. Sputtered silver films of various thicknesses were deposited on glass substrate. Their sheet resistances were measured using standard four point probe. Experimental results agree qualitatively well with simulations. Therefore, it is possible to evaluate sheet resistance from measured Stt. The proposed method is low cost and non-contact, which may be applied to applications relating to conductive thin film characterizations.