XPS Study of the Bonding Properties of Lanthanum Oxide/Silicon Interface with a Trace Amount of Nitrogen Incorporation

Recently, both electrical and material properties of lanthanum oxide have been found to significantly improve with a trace amount of nitrogen doping. This work conducted a detailed investigation on the nitrogen incorporation at the interface by using X-ray photoelectron spectroscopy (XPS) and capacitance–voltage measurements. The process-dependent chemical bonding structures of Si, O, and La atoms at the interface were studied in detail. For samples annealed at and above, the interfacial metallic La–Si bonds were converted into La–N bonds, and some Si–O bonds were found at the interface. These effects resulted in a significant reduction in the interface trap density. The bulk properties of were also improved with the proposed technique as a result of the filling of oxygen vacancies with nitrogen atoms.