THz scattering-type near-field microscopy of semiconductor conductivity and mobility

Ultrahigh-resolution (40 nm) near-field microscopy is demonstrated using a 2.5 THz illumination at 118 mum wavelength. In the experiment, this technique is applied to transistors of the 65-nm technology for THz inspection of semiconductor conductivity and carrier mobility. This is made possible by the extreme THz field concentration at the metallic probe tip. This shows that the THz nanoscope exceeds the diffraction limit of resolution by a factor of 2000, which in effect offers a 100-fold increase in sensitivity. Thus, its 40 nm resolving power matches the needs of modern nanoscience and technology.