Dielectric properties of sol-gel derived high-k titanium silicate thin films

High-k dielectric titanium silicate (TixSi1-xO2) thin films have been deposited by means of an optimized sol-gel process. At the optimal firing temperature of 600 degrees C, the Ti0.5Si0.5O2 films are shown to exhibit not only a dielectric constant (k) as high as similar to 23 but more importantly the lowest leakage current and dielectric losses. Fourier transform infrared spectroscopy shows an absorbance peak at 930 cm(-1), which is a clear signature of the formation of Ti-O-Si bondings in all the silicate films. The developed sol-gel process offers the required latitude to grow TixSi1-xO2 with any composition (x) in the whole 0 <= x <= 1 range. Thus, the k value of the TixSi1-xO2 films can be tuned at any value between that of SiO2 (3.8) to that of TiO2 (k similar to 60) by simply controlling the TiO2 content of the films. The composition dependence of the dielectric constant of the TixSi1-xO2 films is analyzed in the light of existing models for dielectric composites. (c) 2006 Elsevier B.V. All rights reserved.