Abstract
The effects of nitrogen composition in Hf x Ta y N metal-gate electrodes and postmetal annealing (PMA) treatment on the electrical properties of metal-oxide-semiconductor (MOS) devices were investigated in this work. The work function of Hf x Ta y N gate electrodes can be adjusted by incorporating various nitrogen contents. It is found that the Hf x Ta y N metal gate with higher nitrogen content can achieve better electrical characteristics in terms of leakage current and reliability while with only a slight increase in equivalent-oxide-thickness value. The face that only slight variation on electrical characteristics of MOS device with Hf x Ta y N gate electrodes is observed after various PMA temperatures designates the excellent thermal stability of Hf x Ta y N gate electrodes. The present study indicates that Hf x Ta y N is a promising metal-gate-electrode material for advanced MOS devices. © 2007 American Institute of Physics.