The recent commercialization of Vacuum Ultraviolet spectroscopic ellipsometry (VUV SE) instruments means that it is now possible to routinely perform SE measurements at wavelengths below 190 nm. This new capability has obvious implications for lithographic work but also for the characterization of other materials of importance to the Si industry. These are materials that are nominally transparent at long wavelengths but that possess unique absorption signatures in the VUV, such as newly emerging high‐k gate materials (e.g. Al2O3, HfO2, ZrO2, Y2O3) and low k materials (porous SiO2, organo‐silicate glasses), as well as more familiar dielectrics (e.g. SiOxNy, Si3N4, SiOF, and TEOS). We provide a review of recent progress and a critical assessment of the capabilities of VUV SE with respect to a selected examples of these materials, with special emphasis on low k and high k materials. These capabilities include increased access to unique VUV spectral features as a means of tuning process parameters and increased ability to determine the thickness of thin films grown on Si. We also address the initial challenges that had to be overcome in order to develop optical constants at short wavelengths and to enable this sort of materials characterization. © 2003 American Institute of Physics