Comparison of La-based high-k dielectrics: HfLaSiON and HfLaON

For the first time, we present a comparative study on HfLaSiON and HfLaON gate dielectric with an equivalent oxide thickness (EOT) of 0.8nm (T"i"n"v=1.2nm). A detailed DC analysis of I"o"n vs. I"o"f"f shows HfLaON performs somewhat better than HfLaSiON. However, positive bias temperature instability (PBTI) lifetime of HfLaSiON is higher than HfLaON by about 2 orders of magnitude. On the other hand, hot carrier stress lifetime for HfLaSiON was similar to that of HfLaON. From the activation energy and U-trap, we found that the cause of different threshold voltage (V"T) shifts under PBT stress and detrapping was originated from stable electron traps induced by different charge trapping rates.