Multi-Technique Characterization of WSi x films

WSi x films are used extensively for contact, interconnect, and, in some cases, diffusion and Schottky barriers in semiconductor devices 1 . The electrical and barrier properties of these films are affected by a variety of factors, such as film stoichiometry, morphology, impurities, etc. This paper will address the capabilities and limitations of a variety of techniques which are frequently used to characterize WSi x films. Techniques which were studied include: Dynamic and Static Secondary Ion Mass Spectrometry (SIMS), Rutherford Backscattering Spectrometry and Elastic Recoil Detection (RBS/ERD), Auger Electron Spectroscopy (AES), Field Emission Scanning Electron Microscopy (FE-SEM), Total Reflection X-ray Fluorescence (TXRF), Atomic Force Microscopy (AFM), and X-Ray Photoelectron Spectroscopy (XPS). Film characteristics which were studied included surface morphology; grain structure; film stoichiometry; surface and interface oxide thickness and composition; and surface, bulk, and interface impurity concentrations including metallic, atmospheric, and dopant impurities. Cross correlation between the techniques was performed whenever possible in order to compare the relative accuracy of the techniques as well.