TiN x / HfO 2 interface dipole induced by oxygen scavenging

Abstract

Electron barrier height measurements at TiNx/HfO2 interfaces in metal-insulator-metal structures using internal photoemission of electrons reveal a significant (≈1 eV, i.e., about 1/3 of the total barrier height) influence of the opposite electrode material, i.e., Hf versus TiNx. This effect is suggested to be caused by oxygen scavenging from HfO2 by the opposite Hf electrode resulting in generation of positive charges in the oxide above the metal electrode surfaces. Such a considerable interface dipole component demonstrates a principle that may be used to tune the barrier.