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 °C, the Ti0.5Si0.5O2 films are shown to exhibit not only a dielectric constant (k) as high as ∼ 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 ∼ 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.