Fabrication of Robust Triple-Ti1-xAlxN Metal Gate by Atomic Layer Deposition

Abstract

In this study, we fabricate a thermally stable triple-Ti1-xAlxN metal gate for potential use in p-type metal-oxide-semiconductor devices and analyze the impact of Al concentrations in an atomic-layer-deposited Ti1-xAlxN film on the effective work function and the resistivity of the Ti1-xAlxN metal gate. An increase in the Al content in the Ti1-xAlxN film causes an increase in the resistivity of the Ti1-xAlxN film metal gate while improving the thermal stability of the metal gate. By combining the positive effects in terms of the work function and the resistivity, we prepared a triple-layer Ti0.75Al0.25N/TiN/Ti0.75Al0.25N metal gate, which exhibits a work function of 5.04 eV and resistivity of 686 mu Omega cm after thermal annealing at 900 degrees C in N-2 for 30 s, making it suitable for use as a metal gate in pMOS field-effect transistors. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3496032] All rights reserved.