Effect of cluster/particle deposition on atmospheric pressure chemical vapor deposition of SiO2 from four gaseous organic Si-containing precursors and ozone

Abstract

In order to analyze the particle generation and its effect on the SiO 2 thin film in an atmospheric pressure chemical vapor deposition ͑APCVD͒ process using four organic silicon vapors and ozone gas, gas-phase particle generation, growth, transportation and vapor-cluster/particle codeposition processes were studied experimentally and theoretically using a flow-type vertical tube reactor. Decomposition reaction rates of four organic silicon vapors ͑tetraethylorthosilicate, triethoxysilane, tetramethylorthosilicate, and octamethylcyclotetrasiloxane͒ due to the O•oxidation were determined by arranging the number concentrations of the generated particles in Arrhenius plots. The obtained activation energies and frequency factors of reaction rate constants were used to simulate the vapor-cluster/particle codeposition in the CVD process. In the numerical simulation, computational fluid dynamics equations ͑continuity, momentum, and energy conservation equations͒ were solved to evaluate the gas velocity, vapor concentration, and temperature profile inside the reactor. Particle population balance equations based on discrete-sectional presentation for the particle size spectrum were solved coupling with diffusion equations of vapors and clusters/particles. This numerical simulation code could explain the vapor-cluster/particle codeposition in the thin film preparation by the APCVD process. The film growth rate and the surface morphology of the film could be reasonably explained by the deposition flux and the size of deposited clusters/particles obtained as numerical simulation results, respectively.

Energetics and structures of the initial stages of nucleation of (SiO2)Nspecies: possible routes to highly symmetrical tetrahedral clusters

“…Vapour phase manipulation of silica and its controlled deposition is already a well-established technology 2 with the production of vapours of SiO 2 -based species quite routinely performed through the use of siliconcontaining molecular intermediates and highly oxidative conditions. Vapour phase oxidation of silane (SiH 4 ) 3,4 and TEOS (tetraethyl-orthosilicate) 5 molecules, for example, have been successfully employed to produce sources of molecular SiO 2 which can be used to produce very pure silica films and coatings. Although intrinsically relying on the nucleation of pure SiO 2 species, these methods further involve numerous other complex reaction/decomposition routes involving organosilica components.…”

A Global Model of Chemical Vapor Deposition of Silicon Dioxide by Direct-Current Corona Discharges in Dry Air Containing Octamethylcyclotetrasiloxane Vapor

“…The kinetics of plasma-enhanced reactions in the gas-phase have been studied for simple or commonly used chemicals, such as silane (SiH 4 ) and tetraethylorthosilicate (TEOS), (24)(25)(26)(27)(28)(29)(30) for the deposition of silicon dioxide. A few experimental studies exist for the deposition of silicon dioxide using other organic silicon compounds, including hexamethyldisiloxane (HMDSO, Si 2 O(CH 3 ) 6 ) (25,29,(31)(32)(33) and OMCTS, (26,28,30,34,35) and oxygen or ozone. Although the detailed plasma reaction kinetics for HMDSO and OMCTS remains unknown, it has been found that reaction between O 3 and silicone vapor molecules are negligible and the dominant reactions to form precursors for the deposition are those between O and the organiosilicone molecules.…”

“…Fujimoto et al (28) estimated the rate coefficient by assuming Si 8 O 9 (CH 3 ) 14 is the dominant silicon-containing product from the global reaction. They obtained the rate coefficient by matching the numerically predicted particle number concentration using a discrete-sectional model (53) with the measured particle number concentration in the gas phase.…”