Deposition of Hf–silicate gate dielectric on SixGe1−x(100): Detection of interfacial layer growth

The deposition of a stable high-κ dielectric material such as hafnium silicate in direct contact with strained epitaxial SixGe1−x(100) layers on Si(100) provides the prospect of eliminating the Si buffer layer that is currently used to form the gate oxide in SiGe-based devices. In this study, ∼3-nm-thick hafnium silicate films were produced by sputter deposition of hafnium silicide films on precleaned SixGe1−x(100), with subsequent UV-O3 oxidation at room temperature. Prolonged UV-O3 exposure at room temperature leads to the growth of an interfacial layer comprised of a mixture of silicon and germanium oxides. We report on the use of x-ray photoelectron spectroscopy, particularly the x-ray excited Ge (L3MM) Auger feature to optimize UV-O3 exposure time, and minimize the interfacial layer growth of silicon and germanium oxides.