Deposition and Characterization of RP-ALD SiO₂ Thin Films with Different Oxygen Plasma Powers

In this study, silicon oxide (SiO₂) films were deposited by remote plasma atomic layer deposition with Bis(diethylamino)silane (BDEAS) and an oxygen/argon mixture as the precursors. Oxygen plasma powers play a key role in the quality of SiO₂ films. Post-annealing was performed in the air at different temperatures for 1 h. The effects of oxygen plasma powers from 1000 W to 3000 W on the properties of the SiO₂ thin films were investigated. The experimental results demonstrated that the SiO₂ thin film growth per cycle was greatly affected by the O₂ plasma power. Atomic force microscope (AFM) and conductive AFM tests show that the surface of the SiO₂ thin films, with different O₂ plasma powers, is relatively smooth and the films all present favorable insulation properties. The water contact angle (WCA) of the SiO₂ thin film deposited at the power of 1500 W is higher than that of other WCAs of SiO₂ films deposited at other plasma powers, indicating that it is less hydrophilic. This phenomenon is more likely to be associated with a smaller bonding energy, which is consistent with the result obtained by Fourier transformation infrared spectroscopy. In addition, the influence of post-annealing temperature on the quality of the SiO₂ thin films was also investigated. As the annealing temperature increases, the SiO₂ thin film becomes denser, leading to a higher refractive index and a lower etch rate.