Comparative study between conventional macroscopic IV techniques and advanced AFM based methods for electrical characterization of dielectrics at the nanoscale

摘要

High-k dielectrics exhibit strong variations in their electrical characteristics on the nanometer scale due to morphology alteration. Therefore, electrical measurement techniques with nanometer resolution based on atomic force microscopy (AFM) like conductive AFM (cAFM) and tunneling AFM (TUNA) are essentially very well applicable to complement conventional macroscopic current-voltage [IV) techniques. Comparative experiments between conventional IV, cAFM and TUNA measurements on SiO_2 films and on high-k/SiO_2 stacks prove the capability and the accuracy of cAFM/TUNA as advanced methods for electrical characterization of thin dielectric films. Especially TUNA provides the spatial resolution and the current sensitivity required for the characterization of local electrical properties at the nanoscale allowing for the characterization of dielectric layers at high current densities.