Particle generation and thin film surface morphology in the tetraethylorthosilicate/oxygen plasma enhanced chemical vapor deposition process

Abstract

Particle generation by gas-phase nucleation in the plasma enhanced chemical vapor deposition process and its effects on thin film surface morphology were studied experimentally for a conventional radio frequency plasma reactor using tetraethylorthosilicate (TEOS) vapor and oxygen gases. The particles suspended in the plasma space and deposited on the film were observed simultaneously by in situ laser light scattering methods and an ex situ scanning electron microscopic method. The generated particles were trapped in the plasma/sheath boundary under all four experimental conditions, in which TEOS concentrations were 0.5 and 5.0 vol % and reactor pressures were 66.7 and 533.3 Pa (0.5 and 4.0 Torr). The size and amount of particles and the film morphology were found to depend on the TEOS concentration and the reactor pressure. Under the conditions in which highly concentrated particles were generated in plasma, dome-like structures of 50–400 nm in diameter were observed on the thin film surface. The average size of the dome-like structure was comparable to that of the particles generated in plasma.

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.…”

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

“…Some of these efforts include increasing the precursor concentration, the total pressure, and radio frequency (rf) power (Raupp et al 1992;Yi et al 2001). Unfortunately, this leads to the degradation of film properties and the generation of dust particles in the reactor (Fujimoto et al 2000;Setyawan et al 2003).…”

“…Therefore, the presence of dust particles in a plasma reactor has negligible effects on film properties as long as they are not incorporated into the growing layer. However, it has been shown that dust particles may be deposited into growing films during continuous plasma operation (Fujimoto et al 2000), not at the end of the film deposition when the plasma is turned off (Selwyn et al 1989;Setyawan et al 2003Setyawan et al , 2004.…”

Calibration of Polarization-Sensitive and Dual-Angle Laser Light Scattering Methods Using Standard Latex Particles

“…Fujimoto et al (7) and Dorier et al (18) monitored the distribution of dust particles generated in a parallel-plate radio frequency plasma reactor by introducing a polarized beam-expanded laser and detecting the resulting two-dimensional scattered light distribution. McMillin et al (19) reported two-dimensional laser-based imaging measurements for nanoparticle synthesis using a flame CVD reactor.…”