Structure and elastic properties of amorphous silicon carbon nitride films- art. no. 165305

Amorphous SiCxNy films with various compositions were deposited by ion-beam sputtering. The bonding characteristics, Young's modulus, and density of t he films were investigated using x-ray photoelectron spectroscopy (XPS), Fo urier-trans form infrared (FTIR) spectroscopy, surface acoustic wave spectr oscopy, x-ray reflection, and molecular-dynamics (MD) simulations. It was o bserved that the Young's modulus decreases from 260+/-20 to 85+/-12 GPa whi le the density decreases from 3.45+/-0.2 to 2.3+/-0.3 g/cm(3) as the carbon content of the films increases from 0% to 68%. FTIR and XPS spectra indica te an increasing proportion of double and triple bonds with higher carbon c ontent of the films. These experimental results were compared with the Youn g's moduli and the infrared spectra obtained from density-functional-based MD simulations. Also for these model calculations the Young's modulus drops from 237+/-54 to 109+/-25 GPa, as the carbon content increases from 0% to 69%. It can be seen that the formation of C=C, C=N, C=C, and C=N bonds, tog ether with the occurrence of terminating nitrogen atoms for the films with higher carbon content, are responsible for the degradation of the sp(3) net work, and therefore for a lower Young's modulus and density.