Chemical phase separation in Zr silicate alloys: an EXAFS study distinguishing between phase separation with and without XRD detectable crystallization

Abstract

Chemical phase separation at processing temperatures is an important issue for integration of Zr and Hf silicates alloys into advanced CMOS devices. Chemical phase separation into ZrO2 and SiO2 has been detected by different spectroscopic techniques, including Fourier transform infra red, x-ray photoelectron, and x-ray absorption spectroscopy, as well as x-ray diffraction and high resolution transmission electron microscopy imaging. Comparisons between these techniques for Zr silicates identify an unambiguous approach to distinguishing between chemical phase separation with different degrees of micro- and nano-crystallinity. This is important since all modes of chemical separation degrade the dielectric properties required for high-K applications.