Schottky barrier height modulation with Aluminum segregation and pulsed laser anneal: A route for contact resistance reduction

Abstract

We report the first demonstration of a contact technology employing a combination of low energy Aluminum (Al) ion implantation and pulsed laser anneal (PLA) to form nickel silicide (NiSi) with low hole effective Schottky barrier height (Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sup> ) on Si. First, the Al implant energy is reduced over prior work to ensure compatibility with thinner NiSi contacts. Second, the effect of PLA on silicide contact formation is investigated. Third, we show that increasing Al concentration at the silicide/Si interface while keeping the Al concentration within the silicide low is vital for reducing Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sup> . Successful implementation of the contact technology leads to ~77 % reduction in Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sup> , achieving a low Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sup> of 0.104 eV. This opens up new options to lower Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sup> with reduced thermal budget for future technology generations.