Comparison of metal gate electrodes on MOCVD HfO2

Metal gate electrodes of sputtered aluminum (Al), titanium nitride (TiN) and nickel aluminum nitride (NiAlN) are investigated in this work. They are compared with respect to their compatibility with metal organic chemical vapor deposited (MOCVD) hafnium dioxide (HfO2) gate dielectrics. TiN, with a midgap work function of 4.65 eV on SiO2, exhibits promising characteristics as metal gate on HfO2. In addition, encouraging results are presented for the ternary metal NiAlN, whereas classic Al electrodes are found unstable in conjunction with HfO2.