Hydrogenation of Boron Carbon Nitride Thin Films for Low-k Dielectric Applications

Abstract

The influence of hydrogenation on boron carbon nitride (BCN) thin films was investigated for low-k dielectric applications. The BCN thin films were deposited using radio-frequency magnetron sputtering in hydrogen, nitrogen, and argon ambiance. The hydrogen/nitrogen reactive gas flow was varied from 0/10 to 10/10 to achieve a varying range of hydrogen doping. Elemental composition and chemical bonding studies of the films were analyzed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). XPS results confirmed the formation of B-C-N atomic hybridization, and FTIR confirmed the hydrogen doping by evidence of C–H bonds. Metal insulator metal structures were fabricated using Al and BCN thin films to measure electrical properties such as dielectric constant and resistivity. Hydrogenation of BCN caused a 68% decrease in the k value from 6.2 to 2 due to the formation of non-polar bonds. The k value of 2 reported in this study is the lowest value achieved for hydrogenated BCN films deposited by the RF magnetron sputtering technique.