Band-edge metal gate materials for atomic-layer-deposited HfO2 for future CMOS technology

In this paper, two different materials are studied for silicon band edge work function. Sc metal gate with thin interface TaNx layer is investigated for n-channel metal-oxide semiconductor (NMOS) metal gate application. The control of TaNx layer thickness is necessary to achieve improved thermal stability and work function (WF) as low as 4.0 electron volts (eV). RuOx also has been demonstrated for p-channel metal-oxide semiconductor (PMOS) application. RuOx WF tends to increase in comparison with elemental Ru metal. This may be due to improved thin film properties like better adhesion and roughness for RuOx. Overall both Sc and RuOx are revealed as candidate materials for future CMOS technology.