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

Abstract

For the first time, we present a comparative study on HfLaSiON and HfLaON gate dielectric with an equivalent oxide thickness (EOT) of 0.8 nm (T-mv = 1.2 nm). A detailed DC analysis of I-on or I-off 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. (C) 2008 Elsevier B.V. All rights reserved.