Effective Schottky Barrier Height modulation using dielectric dipoles for source/drain specific contact resistivity improvement

Abstract

We demonstrate statistically significant data for specific contact resistivity (ρ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> ) of sub-10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−8</sup> Ω-cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and sub-2×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−8</sup> Ω-cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for N-type and P-type Si respectively on 300mm wafer by introducing ultra-thin ALD high-k dielectric layer(s) between the metal and Si. A 6-terminal Cross-Bridge Kelvin (6T-CBK) structure was used for the extraction to achieve excellent resolution in this small ρ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> range. With the help of measurements from multiple dielectric stacks and Non-Equilibrium Green's Function (NEGF) based quantum transport calculations, we clearly show that the suppression of evanescent metal induced gap states (MIGS) and formation of interface dipole play significant role to reduce the ρ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> as long as the tunneling resistance of the dielectric stack is small. Finally, transient response, break down mechanism and technology benchmarking are discussed which show promise for sub-14nm node applications.