Characteristics of low-k SiOC(–H) films deposited at various substrate temperature by PECVD using DMDMS/O2 precursor

We report on the influence of substrate temperature on SiOC(–H) thin films deposited on p-type Si(100) substrates by plasma enhanced chemical vapor deposition (PECVD) with dimethoxydimethylsilane (DMDMS) and oxygen gas as precursors. The films were deposited at various substrate temperatures with a radio frequency (rf) power of 500 W and working pressure of 700 mTorr. Fourier transform infrared (FTIR) spectroscopy was used in the absorbance mode over the range of 400 to 4000 cm−1 which showed the various bonding configurations such as Si–O–Si(C), Si–CH3,–OH, and CHn bonds in the SiOC(–H) films. The X-ray photoelectron spectroscopy (XPS) was used to study the binding energies of Si–C, SiO–C3, SiO2–C2, SiO3–C, Si–O2, C–C, C–H and C–O bonds in the SiOC(–H) films as a function of the substrate temperature. The dielectric constant of the SiOC(–H) films was measured using a metal insulator semiconductor (MIS, Al/SiOC(–H)/p-Si) structure at 1 MHz frequency. The lowest dielectric constant of the films deposited at room temperature was 2.22 and was achieved with DMDMS/O2 precursor.