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

Published

September 1, 1999

Author(s)

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

Abstract

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

Pub Type

Conferences

Keywords

ellipsometry, optical constants, pentoxide, spectroscopic, Ta₂O₅, tantalum

Citation

Richter, C. , Nguyen, N. and Alers, G. (1999), 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, Proc., Mater. Res. Soc. Symp. , Pittsburgh, PA, USA (Accessed September 18, 2024)