Deposition of SiO2 films from different organosilicon/O2 plasmas under continuous wave and pulsed modes

We report on the microwave plasma-enhanced chemical vapor deposition (PECVD) of silicon dioxide from oxygen/tetraethoxysilane and oxygen/hexamethyldisiloxane under continuous wave and pulse modes. The influence of process parameters such as oxygen/organosilicon flow rate ratio, pressure and microwave power on the film characteristics has been investigated. We were interested in the film deposition rate, density, refractive index and atomic concentrations. Mass spectrometry and Langmuir probe measurements provided useful information about the gas phase and the plasma discharge. A comparison was made between the properties of films deposited with continuous wave and with equivalent powered pulsed plasma. The effect of the pulse frequency and of the pulse duty cycle was also studied.