AVS 53rd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM-ThP

Paper EM-ThP40
Suppression of Chemical Phase Separation in Hf and Ti Si Oxynitride Alloys with High Silicon Nitride Content

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Electronic Materials and Processing Poster Session
Presenter: S. Lee, NC State University
Authors: S. Lee, NC State University
G. Lucovsky, NC State University
J. Luning, Stanford Synchrotron Radiation Lab
Correspondent: Click to Email
There are two significant materials issues that limit implementation of high and medium k dielectrics into MOS devices. These are grain-boundary defects in high-k transition metal(TM)/rare earth elemental/complex oxides, and chemical phase separation (CPS) at temperatures too low for thermal budget requirements, <900°C, in medium-k non-crystalline TM silicate and nitrided silicates. All Zr, Hf and Ti silicate compositions display CPS for annealing temperatures of ~900°C. This paper is part on an ongoing study of pseudo-ternary SiO@sub 2@-Si@sub 3@N@sub 4@-Zr/Hf/TiO@sub 2@ alloys (hereafter Zr/Hf/Ti Si oxynitrides). In previous studies of Zr Si oxynitrides, it was demonstrated that compositions with relatively low Si@sub 3@N@sub 4@ content <30%, display CPS at temperatures ~900°C. In marked contrast, Zr Si oxynitrides with higher Si@sub 3@N@sub 4@ content >35%, and approximately equal concentrations of ZrO@sub 2@ and SiO@sub 2@, ~ 30-32%, are stable for annealing in inert ambients at temperatures to 1100°C. The results of this paper demonstrate essentially the same behaviors with respect to low and high Si@sub 3@N@sub 4@ content for Hf Si oxynitrides, Ti Si oxyntirdes, and equally importantly, for Hf-Ti alloy Si oxynitrides. Three different spectroscopies have been used to detect CPS, or the absence of CPS: Fourier transform infrared spectroscopy, derivative x-ray photoelectron spectroscopy for the O 1s core level, and derivative near edge x-ray absorption spectroscopy (NEXAS) for the O K@sub 1@ and N K@sub 1@ edges. The NEXAS spectra also provide direct confirmation of a chemical bonding self-organization that prevents nucleation and growth of a nanocrystalline TiO@sub 2@ or HfO@sub 2@ phase that is a necessary precursor to a CPS process.