Specific Contact Resistivity Reduction Through Ar Plasma-Treated TiO_2−x Interfacial Layer to Metal/Ge Contact

Abstract

We demonstrate contact resistivity reduction by inserting an Ar plasma-treated TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2-x</sub> heavily doped interfacial layer to metal/semiconductor contact to overcome a Fermi-level pinning problem on germanium (Ge). A specific contact resistivity of 3.16 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> Ω · cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> on moderately doped n-type Ge substrate (6 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">16</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> ) was achieved, exhibiting ×584 reduction from Ti/Ge structure, and ×11 reduction from Ti/undoped TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Ge structure. A novel doping technique for TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> interfacial layer at low temperature using Ar plasma was presented to lower S/D contact resistance in Ge n-MOSFET.