Measurement of Dipoles/Roll-Off /Work Functions by Coupling CV and IPE and Study of Their Dependence on Fabrication Process

Abstract

We study the effective metal gate work function (WF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Meff</sub> ) of different metal/high-κ gate stacks. Both capacitance versus voltage measurement and internal photo emission measurement were used, leading to a better understanding of the WF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Meff</sub> variations. We demonstrate that these variations are related to two main process dependent parameters, a voltage drop at the high- κ/SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> interface and the metal work function. These two parameters are studied for various process conditions.