Plasma enhanced chemical vapor deposition of silicon oxide films with divinyldimethylsilane and tetravinylsilane

Abstract

Carbon-doped silicon oxide (SiCOH) low-k films were deposited with plasma enhanced chemical vapor deposition (PECVD) using divinyldimethylsilane (DVDMS) with two vinyl groups and tetravinylsilane (TVS) with four vinyl groups compared with vinyltrimethylsilane (VTMS) with one vinyl group. With more vinyl groups in the precursor, due to the crosslinking of the vinyl groups, the film contains more of an organic phase and organic phase became less volatile. It was confirmed that the deposition rate, refractive index, and k value increase with more vinyl groups in the precursor molecule. After annealing, the SiCOH films deposited with DVDMS and TVS showed a low dielectric constant of 2.2 and 2.4 at optimum conditions, respectively. In both cases, the annealed film had low leakage current density (J=6.7×10−7A∕cm2 for SiCOH film of DVDMS and J=1.18×10−8A∕cm2 for SiCOH film of TVS at 1MV∕cm) and relatively high breakdown field strength (E>4.0MV∕cm at 1mA∕cm2), which is comparable to those of PECVD SiO2.