Measurements of dielectric properties of TiO2 thin films at microwave frequencies using an extended cavity perturbation technique

This research provides a simple method to measure the dielectric properties of thin films at microwave frequencies. The cavity perturbation theory is applied to the measurement method. The measured frequency is in X-band (8.2–12.4 GHz). The titanium dioxide thin films are deposited by the RF reactive magnetron sputtering method onto borosilicate glass substrates. The microwave complex permittivity of films is then measured by the extended cavity perturbation technique. It was found the dielectric constants of titanium dioxide thin films strongly depend on the partial pressure of oxygen. The dielectric constant maximized at a value of 95 with 30% O2. This is the first report that confirms the high dielectric constant of TiO2 thin films at microwave frequencies which shows its potential for high-K related microwave devices.