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Spectroscopic Ellipsometry of Ta205 On Si, in Ultrathin SiO2 and High-K Materials for ULSI Gate Dielectrics, edited by H. R. Huff, C. A. Richter, M. L. Green, G. Lucovsky, and T. Hattori



Curt A. Richter, Nhan Van Nguyen, G A. Alers


In this paper, we present the results of spectroscopic ellipsometry (SE) studies of Ta205 films on Si. Based on these results, we have experimentally determined an effective method for analyzing SE measurements of Ta205. A set of CVD-grown Ta205 films on silicon - with thicknesses raging from below 10 nm to approximately 60 nm thick - was investigated by SE in an effort to improve optical film thickness metrology for Si/Ta205. The samples were measured across the spectral range 1.5 eV to 6.0 eV by using a well-characterized, high-accuracy rotating-analyzer-type ellipsometer. We present an analysis method, based upon a Tauc-Lorentz parameterization of the optical properties of Ta205, that properly describes the SE data. We also demonstrate how optical properties are affected by the presence of an interlayer at the Si/Ta205 interface. Our results show small, but meaningful variations in optical parameters resulting from variations in deposition processes and annealing conditions. This work demonstrates that SE can be used successfully to characterize the category of alternate gate dielectrics.
Proceedings Title
Proc., Mater. Res. Soc. Symp.
Conference Location
Pittsburgh, PA, USA


ellipsometry, optical constants, pentoxide, spectroscopic, Ta<sub>2</sub>O<sub>5</sub>, tantalum


Richter, C. , Nguyen, N. and Alers, G. (1999), Spectroscopic Ellipsometry of Ta<sub>2</sub>0<sub>5</sub> On Si, in Ultrathin SiO<sub>2</sub> and High-K Materials for ULSI Gate Dielectrics, edited by H. R. Huff, C. A. Richter, M. L. Green, G. Lucovsky, and T. Hattori, Proc., Mater. Res. Soc. Symp. , Pittsburgh, PA, USA (Accessed June 16, 2024)


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Created August 31, 1999, Updated October 12, 2021