FABRICATION AND CHARACTERIZATION OF EVANESCENT MICROWAVE PROBES COMPATIBLE WITH ATOMIC FORCE MICROSCOPE FOR SCANNING NEAR-FIELD MICROSCOPY

摘要

The design and microfabrication of silicon co-axial evanescent microwave probes (EMP) compatible with atomic force microscope (AFM) imaging was discussed. Scanning EMP (SEMP) imaging is suitable for nondestructive surface and subsurface characterization of materials over a wide frequency range-between 0.1 GHz and 140 GHz. The micro-fabricated EMP consists of a silicon V-shaped cantilever beam, a co-axial tip, and aluminum co-planar waveguides. The coaxial tip has an apex radius of ～80 A. The tip itself is oxidation-sharpened heavily-doped silicon surrounded by an oxide layer that acts as insulator and covered with an aluminum co-axial layer. The tip apex is electrically connected to a strip of aluminum that forms the active part of the waveguide. The design and microfabrication procedure are described. Mechanical and electrical characterizations are discussed. Contact mode and SEMP surface measurement results are reported. The first ever simultaneous contact AFM and scanning near-field microwave microscopy (SNMM) surface imaging are presented. Using the microwave measurement along with the AFM imaging opens up a new window to see inside the materials and sets the stage for hyperspectral imaging of organelles of biological objects as well as electronic devices and structural materials.