Mechanical property of the low dielectric carbon doped silicon oxide thin film grown from MTMS/O2 source

Carbon doped silicon oxide (SiOC(–H)) films with low dielectric constant were deposited on a p-type Si(1 0 0) substrate by using inductively coupled plasma chemical vapor deposition with methyltrimethoxysilane (MTMS: CH3Si(OCH3)3) precursor and oxygen gases. The Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) was used to investigate the bonding configurations and atomic concentrations in the films. The elastic modulus and hardness of the films were evaluated by nano-indentation measurements. The dielectric constant of the SiOC(–H) composite film depends on the relative carbon concentration and the content of the ring link mode in SiOC(–H) bonding structure. Nano-indenation measurements showed decreased elasticity of the film, as well as decreased hardness upon carbon incorporation. The elasticity of as deposited films decreased as MTMS flow rate increased, which is decreased from 0.11 to 0.01 and the annealed SiOC(–H) films changed a little from 0.001 to 0.002. A clear correlation between the mechanical characteristics was found as a function of carbon content in the film. The dielectric constant decreases from 3.1 to 2.4 in the as deposited SiOC(–H) films and for the annealed films the dielectric constant decreases from 3.2 to 2.2.