Investigation of gas phase species and deposition of SiO2 Films from HMDSO/O2 plasmas

SiOxCyHz films are deposited by radio frequency plasma enhanced chemical vapor deposition (PECVD) using a mixture of HMDSO and oxygen as source gases. The gas phase species produced in HMDSO and HNIDSO/O-2 plasmas are investigated by optical emission spectroscopy (OES) and mass spectrometry (MS). These data reveal that oxygen dilution causes strong dissociation of the HMDSO monomer. The film composition was investigated with X-ray photoelectron spectroscopy (XPS) and Fourier-transform, infrared (FF-IR) spectroscopy. Low O-2 dilution (<= 50%) results in the deposition of polymer-like SiOxCyHz films while higher O-2 dilution (>= 80%) results in the deposition of inorganic SiO2-like films. Surface energy measurements show that the SiO2 films have higher surface energy than the polymer-like SiOxCyHz films. Deposition rates are measured with variable angle spectroscopic ellipsometry and are strongly dependent on the percentage of O-2 dilution in the feed mixture.