Origin of Fermi-level depinning at TiN/Ge(001) interfaces: first-principles study

Abstract

The origin of Fermi-level (FL) depinning at TiN/Ge interfaces was studied using first-principles calculation. It was shown that FL pinning occurs at abrupt clean interfaces, while depinning occurs at interfaces with N-rich interface layers such as TiN 2 and Ge 3 N 4 , which is in good agreement with the experiments. By analyzing electronic structures, we found that the termination of interface Ge atoms by N atoms, i.e. the production of interface N-Ge bonds, is the key to realize FL depinning at TiN/Ge interfaces. The effects of missing N-Ge interface bonds were also discussed.

(Invited) Schottky Barrier Height Control at Metal/Ge Interface by Insertion of Nitrogen Contained Amorphous Layer

“…From detailed structural analyses, it was clarified that the FLP alleviation is induced by a nitrogen containing amorphous interlayer (a-IL) which is formed during TiN (ZrN) sputter-deposition. Based on these experimental results, we have suggested an extrinsic states model associated with a nitrogen related interfacial dipole (27,28).…”