Abstract
Synchrotron radiation photoelectron spectroscopy (SRPES) is used to investigate the in-situ formation of ultra thin Mn silicate copper diffusion barrier layers on SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . It was shown that high temperature annealing results in the growth of Mn silicate, the stoichiometry of which was calculated to be MnSiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> . SRPES results also show that the interaction of metallic Mn with SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is self limiting at high temperature. In a separate experiment the role of oxygen in determining the extent of the interaction between the deposited Mn and the SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> substrate was investigated. Using X-ray photoelectron spectroscopy (XPS) it has been shown that a metallic Mn film (~1 nm) cannot be fully converted to Mn silicate following vacuum annealing to 500°C. Transmission electron microscopy (TEM) analysis suggests the maximum MnSiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> layer thickness obtainable using metallic Mn is ~1.7 nm. In contrast, a ~1 nm partially oxidized Mn film can be fully converted to Mn silicate following thermal annealing to 400°C, forming a MnSiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> layer with a measured thickness of 2.6 nm. TEM analysis also clearly shows that MnSiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> growth results in a corresponding reduction in SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> layer thickness. Based on these results it is suggested that the presence of Mn oxide species at the Mn/SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> interface facilitates the conversion of SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> to MnSiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> .
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