High-spatial-resolution semiconductor characterization using a microwave eddy current probe

We report on the design and application of a high-resolution microwave eddy current probe that consists of a microfabricated coil with inner and outer widths of 6 and 20 μm, respectively, integrated with a coplanar waveguide. In addition to improved spatial resolution, we implement a stub-matching technique, which enables us to make high-sensitivity measurements. We demonstrate the utility of our device by measuring the minority-carrier lifetime in a thin In0.53Ga0.47As film. Although our present demonstration does not allow us to reuse the sample, with minor changes this technique can be made noncontact and nondestructive.