Effects of High Temperature Annealing on the Dielectric Function of Ta2O5 Films Observed by Spectroscopic Ellipsometry

Published

November 6, 2000

Author(s)

Nhan Van Nguyen, Curt A. Richter, Yong J. Cho, G A. Alers, L. A. Stirling

Abstract

Post-deposition annealing of high-k dielectric Ta₂O₅ films to eliminate contaminations can adversely cause the films to crystallize, which can be detrimental to their CMOS device performances. In this letter, we will show that spectroscopic ellipsometry (SE) can be used to quickly and nondestructively detect such crystallization by identifying the two relatively sharp absorption peaks at 4.7 eV and 5.2 eV in the complex dielectric function of the films. Such peaks are absent in amorphous Ta₂O₅ films. In general, these sharp structures in the dielectric function are expected from the presence of long-range order in materials, which produces singularities in their interband density of states. Using this approach, will show that Ta₂O₅ films become crystalline when annealed at or above 750:C and remain amorphous below 700: C.

Citation

Applied Physics Letters

Volume

77

Issue

19

Pub Type

Journals

Keywords

Ta₂ O₅, spectroscopic ellipsometry, ellipsometry, thin film, high-K dielectric, dielectric function, index of refraction annelaing, optical properties

Citation

Nguyen, N. , Richter, C. , Cho, Y. , Alers, G. and Stirling, L. (2000), Effects of High Temperature Annealing on the Dielectric Function of Ta₂O₅ Films Observed by Spectroscopic Ellipsometry, Applied Physics Letters (Accessed October 18, 2025)