Four point probe structures with buried and surface electrodes for the electrical characterization of ultrathin conducting films

Test structures for the electrical characterization of ultrathin conductive films are presented based on electrodes on which the ultrathin film is deposited. Two different designs are discussed: a novel design with buried electrodes and a conventional design with electrodes at the surface. This work includes test structure design and fabrication, and the electrical characterization of ALD TiN films down to 4 nm. We demonstrate that the novel test structures provide the same results as the conventional structures, and have the advantage of broader materials choice (i.e. conductor-dielectric combination). The proposed structures can be used successfully to characterize sub 10 nm films.