Effect of catalyst HF concentration on the electrical characteristics of ultra low-k materials

The effects of catalyst HF concentration on the dielectric and electrical properties of SiOF films are discussed. From the current density-voltage and capacitance-voltage curves, we observed that the film catalyzed with the special concentration of HF (the ratio of HF/H2O = 1/5) shows good moisture resistance, low leakage current (10-11 A/cm2 at 1 MV/cm) and high breakdown field (6 MV/cm), which can be explained by the results of Fourier transform infrared spectra. The dielectric constant value is also very low and reaches about 1.75 after annealing at the temperature of 450 °C. Therefore, the concentration of HF catalyst is an important factor in the sol-gel process.