Investigation of Molybdenum Nitride Gate on SiO[sub 2] and HfO[sub 2] for MOSFET Application

Abstract

It has been reported that the work function of nitrided molybdenum (MoN) can be modulated by the atomic ratio of NMo and is suitable for gate material of complementary metal oxide semiconductor devices. In this work, we investigated the characteristics of Mo Nx prepared by reactively sputtering deposition from the gate electrode point of view. The main phase of the Mo Nx films is MoN(200). As the NMo ratio increases, the microstructure of Mo Nx film tends to be amorphous-like and the resistivity increases. After high-temperature annealing, the phase remains stable and grain size increases slightly. The Hf O2 film has better immunity to sputtering damage than Si O2 film; therefore, the sputtering deposition method could be a choice of metal gate deposition as Hf O2 -based dielectric is used. The work function of Mo Nx increases with the increase of nitrogen content and tends to saturate at the valence band of Si. No Fermi-pinning effect is observed on Hf O2 film. The work function and thermal stability of Mo Nx show good thermal stability on both Si O2 and Hf O2 films up to 800°C at least. All of these results indicate that MoN is a good candidate of gate electrode for p-type metal oxide semiconductor field effect transistors (pMOSFETs) or fully depleted SOI devices. © 2006 The Electrochemical Society. All rights reserved.