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



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


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.
Applied Physics Letters


Ta<sub>2</sub> O<sub>5</sub>, spectroscopic ellipsometry, ellipsometry, thin film, high-K dielectric, dielectric function, index of refraction annelaing, optical properties


Nguyen, N. , Richter, C. , Cho, Y. , Alers, G. and Stirling, L. (2000), Effects of High Temperature Annealing on the Dielectric Function of Ta<sub>2</sub>O<sub>5</sub> Films Observed by Spectroscopic Ellipsometry, Applied Physics Letters (Accessed June 25, 2024)


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Created November 5, 2000, Updated October 12, 2021