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We report on thermal stability of the effective work function (EWF) of RuO2-rich Ru–Si–O gate electrodes intended for high-performance p-channel metal-oxide-semiconductor field-effect transistors. The Ru–Si–O thin films, with the composition 15% and 40% of SiO2, were grown by atomic vapor deposition at either 380 or 450°C on SiO2∕Si substrate. The Ru–Si–O thin film with 15% of SiO2 deposited at 450°C was evaluated as the most thermally stable gate electrode showing the EWF of 5.0eV after rapid thermal annealing (RTA) at 800°C∕10s in nitrogen followed by forming gas annealing (FGA). Transmission electron microscopy studies show that Ru–Si–O films are composed of RuO2-rich nanograins embedded in the SiO2-rich amorphous matrix. The Ru–Si–O films show enhanced thermal stability, as we observe reduction of RuO2 to Ru nanograins without disintegration of the layers after RTA at 900°C∕10s and subsequent FGA 430°C∕30min. Resistivity of the Ru–Si–O films as a function of temperature was found to be dependent on composition as well as deposition temperature. Resistivity of the Ru–Si–O film with 15% of SiO2 deposited at 450°C shows metalliclike character with a residual resistivity ratio of 1.3. The effect of RTA and FGA on the resistivity of the Ru–Si–O films is discussed in terms of the increase in connectivity and grain size.

We have investigated metal gate electrodes for use with high k HfSiOx gate dielectric films using AVD ® and ALD technology. First, we report on the characterization of the AVD ® and ALD deposition techniques where both HfO 2 and SiO 2 are combined for the formation of HfSiOx. Nitrogen is then incorporated using both in-situ and ex-situ methods to form HfSiON and the resulting film properties are compared. Using an AVD process a work-function of >4.7eV for Ru and RuO 2 gate electrode metals in combination with HfSiOx was obtained. A TaN-based metal gate was also characterized to target a promising pMOS solution using different compositions. Together with its high flexibility and composition control, both ALD and AVD ® can become key processes for advanced high-k dielectrics as well as compatible CMOS metal electrodes.

Ultra-thin ruthenium (Ru) layers were fabricated by pulsed metal organic chemical vapor deposition in an Aixtron Tricent reactor using a metal-organic Ru precursor. Layer deposition was performed on different metal barrier combinations and on Al2O3 dielectric layers used in the fabrication of advanced Metal-Insulator-Metal (MIM) capacitor structures and on thermal SiO2 as reference structure. Ru layers with a thickness of 10 nm were characterized by Spectroscopic Ellipsometry (SE) and additional reference methods such as Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), and X-Ray Reflectometry (XRR). As deposited and in situ annealed Ru layers were characterized by SE applying Drude-Lorentz- and Effective Medium Approximation (EMA) models. It was shown that the deposited layers consist of a Ru-RuO2 bilayer structure. By in situ annealing, the RuO2 layer thickness is reduced and highly pure Ru films are obtained. On the metal barriers the formation of a metal oxide interface, which is related to the deposition process, was determined