Influence of HF catalyst on the microstructure properties of ultra low-k thin films prepared by sol-gel method

This paper reports that by using the hydrofluoric acid (HF) as the acid catalyst, F doped nanoporous low-k SiO_2 thin films have been prepared by means of sol-gel method. The characterization of atomic force microscopy and Fourier transform infrared spectroscopy demonstrates that the HF catalyzed films are more hydrophobic. The N_2 adsorption/desorption experiments show that the suited introduction of HF increases the porosity and decreases the pore size distribution (about 10\,nm) in the films. The above results indicate that the hydrofluoric acid is the more suitable acid catalyst than the hydrochloric one for preparing nanoporous ultra low-k SiO_2 thin films.