Incorporation of Dust Particles into a Growing Film During Silicon Dioxide Deposition from a TEOS/O₂Plasma

Abstract

The effects of gas flow rate on particle formation and film deposition during the preparation of silica thin film using a TEOS/O 2 plasma were investigated. Particle formation and growth are suppressed with increasing gas flow rates. The film deposition rate increases with increasing gas flow rate, reaches a maximum value, and eventually decreases again. However, the uniformity of the film tends to degrade at high gas flow rates. At a high gas flow rate, some particles trapped in the sheath near the grounded electrode pass through the sheath to reach the substrate and are then embedded in the growing film. A self-consistent sheath model combined with particle force balance based on charge fluctuation was developed to explain these experimental findings qualitatively. The model reveals that charge fluctuation is a key factor for the particle to overcome the potential barrier of the negatively charged particles to pass through the sheath, eventually reaching the substrate. The model further shows that the probability of a particle being deposited on the substrate is higher for increased gas flow rates, which correctly predicts the experimentally observed trend.

Health and Safety Issues in Emerging Surface Engineering Techniques

“…The formation of nanoparticles by homogeneous nucleation of the intermediate species during the deposition of siloxane coating (using tetraethyl orthosilicate or silane as a precursors) is a common phenomenon (29,(31)(32)(33)(34)(35)(36)(37) in CVD techniques (such as thermal CVD, low pressure PECVD, and atmospheric pressure plasma CVD). This is believed to be due to the excess gas-phase reaction between precursors and process gas.…”