Electrical characterization of low-k films with nano-pore structure prepared with DMDMOS/O2 precursors

Carbon doped SiOC(–H) films with low dielectric constant were deposited on p-type Si(100) substrates by using plasma enhanced chemical vapor deposition from dimethyldimethoxysilane [DMDMOS, C4H12O2Si] and oxygen gas as precursors. The SiOC(–H) films were deposited at different radio frequency (rf) powers from 400 to 800 W. Fourier transform infrared was used to investigate the bonding configurations of the SiOC(–H) films. The influence of the rf power effect on the formation mechanism of SiOC(–H) films was correlated. Relative content of Si–CH3 bonds decreased with increasing rf power up to 700 W whereas –CHn related bonds increased with rf power. However, the film with an rf power of 800 W shows increase of Si–CH3 and decrease of –CHn bonds, behaving like Si–O2 film. The leakage current density was found to be 2.7 × 10− 9 A/cm2 and also the lowest dielectric constant of 2.04 for the SiOC(–H) films deposited with an rf power of 700 W.