A study on structural and electrical properties of low dielectric constant SiOC(–H) thin films deposited via PECVD

Low-dielectric constant SiOC(–H) films were deposited on p-type Si(100) substrates using plasma enhanced chemical vapor deposition (PECVD) at different radio frequency (rf) powers. The structural characteristics of the SiOC(–H) films were characterized using Fourier transform infrared spectroscopy (FTIR) in the absorbance mode. The bonding configurations of the SiOC(–H) films remained unchanged upon annealing, showing their good thermal stability. Electrical characteristics of the SiOC(–H) thin films with Al/SiOC(–H)/p-Si(100)/Al metal-insulator-semiconductor (MIS) structures were analyzed using capacitance–voltage (C–V) and conductance–voltage (G/ω–V) at different frequencies. The conductance and the capacitance measurements were used to extract the interface state density in the MIS structures. From the experimental data and the subsequent quasi-static C–V analysis, the energy distribution of interface state density was obtained. The interface state density of the as-deposited and 400 °C annealed MIS structures increased with increasing rf powers, whereas the fixed charge density decreased with increasing rf powers. The interface state densities and their electrical properties of the SiOC(–H) films strongly affected by the radio frequency power.

► Low-dielectric constant SiOC(–H) films were grown on p-Si(100) substrates by PECVD.
► Radio frequency (rf) powers were varied to study the electrical properties of SiOC(–H) film.
► Electrical properties of SiOC(–H) thin films with Al/SiOC(–H)/p-Si(100)/Al were studied.
► Conductance and capacitance methods were used to extract the interface state density.
► Electrical properties of the SiOC(–H) films strongly affected by the rf power.