Performance Enhancement of Self-Aligned Coplanar TFTs With ALD-IGZO Channels via Effective Doping From Interlayer Dielectric

Abstract

A doping technique to form the conductive source/drain regions of self-aligned coplanar thin-film transistors (TFTs) employing In-Ga-Zn-O (IGZO) channels prepared by atomic-layer deposition was uniquely demonstrated. The electrical resistivity of the IGZO film was reduced to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${2}.{88}\times {10} ^{-{4}}\,\,\Omega \cdot $ </tex-math></inline-formula> cm after simple Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> interlayer dielectric deposition process using <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{H}_{{2}}\text{O}$ </tex-math></inline-formula> . The field-effective mobility of the fabricated IGZO TFTs was 23.4 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V.s and trustworthy device stabilities were confirmed. Furthermore, small values of the channel width-normalized contact resistance could be obtained to be as low as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8.5~\Omega \cdot $ </tex-math></inline-formula> cm.