| Abstrakt: |
For nMOS devices with HfO2, a metal gate with a very low workfunction is necessary. In this letter, the effective workfunction (Φm,eff) values of ScNx gates on both SiO2 and atomic layer deposited (ALD) HfO2 are evaluated. The ScNx/SiO2 samples have a wide range of 4m,eff values from ∼3.9 to ∼4.7 eV, and nMOS-compatible Φm,eff values can be obtained. However, the ScNx gates on conventional post deposition- annealed HfO2 show a relatively narrow range of Φm,eff values from ∼4.5 to ∼4.8 eV, and MOS-compatible Φm,eff values cannot be obtained due to the Fermi-level pinning (FLP) effect. Using high-pressure wet post deposition annealing, we could dramatically reduce the extrinsic FLP. The Φm,eff value of ∼4.2 eV was obtained for the ScNx gate on the wet-treated HfO2. Therefore, ScNx metal gate is a good candidate for nMOS devices with ALD HfO2. [ABSTRACT FROM AUTHOR] |
