Today there is no doubt that oxygen re-distribution at the metal/oxide interface represents the major driving force of
interface barrier and effective work function (EWF) variation, at the same time atomic picture of this crucial process
remains incomplete: most of the attention has been devoted so far to the electron states inside the near-interface
insulating layer leading to the break of electro-neutrality while the ―fate‖ of oxygen leaving the insulating film as well
as its influence on the EWF remains unknown. The complexity of the problem is related to formation of interlayers (ILs)
at the metal/insulator interfaces due to interdiffusion and chemical reactions during the synthesis of such systems.
Analysis of different metal-oxide-semiconductor gate stacks reveals the increasingly important role of such ILs, which
may impact the functionality of the devices by, for example, affecting the EWF of electrodes. To progress towards
better understanding the physics and chemistry of the metal/oxide interface barrier formation, the physical mechanism
behind the metal/insulator barrier variations will be studied using X-ray spectroscopic methods for the practically
relevant stacks used in charge trapping (flash) memory cells and in advanced logic and memory semiconductor devices.
Also the influence of different ILs grown by atomic layer deposition process between the TiN electrode and oxide in
some stacks on the amount of oxidized Ti at the interface will be demonstrated. It will be shown that the amount of TiO2
phase can be effectively controlled, i.e., increased or decreased, during the atomic layer deposition process enabling
engineering of vacancy-mediated processes.