Compositional effect on the dielectric properties of high-k titanium silicate thin films deposited by means of a cosputtering process
- Institut National de la Recherche Scientifique INRS-Energie, Materiaux et Telecommunications, 1650, Boulevard Lionel-Boulet, C.P. 1020, Varennes, Quebec J3X 1S2 (Canada)
We report on the successful growth of high dielectric constant (high-k) titanium silicate Ti{sub x}Si{sub 1-x}O{sub 2} thin films of various compositions (0{<=}x{<=}1) at room temperature from the cosputtering of SiO{sub 2} and TiO{sub 2} targets. The developed process is shown to offer the latitude required to achieve not only a precise control of the film composition but an excellent morphology (i.e., dense films with low roughness) as well. The Fourier transform infrared and x-ray photoelectron spectroscopy characterizations have evidenced the presence of Ti-O-Si type of atomic environments, which is the fingerprint of the titanium silicate phase. The titanium silicate films are found to exhibit excellent dielectric properties with very low dielectric losses [tan({delta})<0.02] regardless of their composition. The dielectric constant of the films is found to increase with their TiO{sub 2} content from 4 (for pure SiO{sub 2} films) to 45 (for TiO{sub 2}). On the other hand, increasing the TiO{sub 2} content of the films is also shown to degrade significantly their leakage current. Nevertheless, titanium silicate films with almost equiatomic composition (x{approx}0.45) are found to exhibit an excellent trade-off between a high-k value ({approx}18) and low leakage current ({approx}5x10{sup -7} A/cm{sup 2} at 1 MV/cm). Finally, the compositional dependence of the dielectric properties of the Ti{sub x}Si{sub 1-x}O{sub 2} films is discussed in terms of bonding states and optical band gap.
- OSTI ID:
- 20777189
- Journal Information:
- Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 24, Issue 3; Other Information: DOI: 10.1116/1.2180267; (c) 2006 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
- Country of Publication:
- United States
- Language:
- English
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