On the nature of the interfacial layer in ultra-thin TiN/LaLuO3 gate stacks

Mitrovic, I. Z., Hall, S., Sedghi, N., Simutis, G., Dhanak, V. R., Bailey, P., Noakes, T. C. Q., Alexandrou, I., Engstrom, O., Lopes, J. M. J. and Schubert, J. (2012) On the nature of the interfacial layer in ultra-thin TiN/LaLuO3 gate stacks. Journal of Applied Physics, 112 (4). 044102. ISSN 0021-8979

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Abstract

We present a detailed investigation on the nature of the interfacial layer (IL) in ultra-thin
TiN/LaLuO3 (LLO) gate stacks, which is of importance to facilitate CMOS scaling. The molecular beam deposited LaLuO3 films are found to be amorphous by high-resolution transmission electron microscopy. A �A° thick LaLuO3/interlayer transition observed by medium energy ion scattering correlates with the presence of a dual silicate/SiO2-like interfacial layer derived from the analysis of photoelectron line positions and electron energy loss spectra. A theoretical model is used for the dielectric transition in a bi-layer LaLuO3/IL structure, linking physical and electrical characterization data. The obtained leakage current of 10�3 A/cm2 at 1.5V and equivalent oxide thickness of 0.75 nm for TiN/LaLuO3 gate stacks are adequate for scaling in the 14-12 nm node.

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