Comparative study of plasma-deposited fluorocarbon coatings on different substrates

International audienceThe deposition of hydrophobic fluorocarbon coatings from C 2 F 6 and C 2 F 6 -H 2 rf discharges on different substrates was examined. Polyester textile, glass and two different ceramic compounds were used as substrates. The effect of the total gas pressure, the rf power dissipation and the deposition time on the hydrophobic character of the samples was investigated. Films deposited on polyester textiles at low pressure (0.03 mbar) and power consumption (16 mW/cm 2) using pure C 2 F 6 presented the highest water contact angles (~150 o). On the other hand, the addition of hydrogen was necessary in order to deposit stable hydrophobic coatings on glass and ceramic substrates. Coatings deposited on glass at intermediate deposition rates (~100 Å/min) and pressures presented the highest angles (~105 o). Concerning the heavy clay ceramics, samples treated in low pressure (0.05 mbar) and low power (16 mW/cm 2) discharges showed the highest contact angles The deposition time was found to play an important role on the hydrophobicity and long term behavior of porous and rough substrates

Joint Russian and Bulgarian Academies of Sciences Database of Intermolecular Potentials and Diffusion Coefficients for Components of the CVD Processes in Microelectronics 1

The goal of the database (DB) EPIDIF-JRB is to promote the modeling of gas-phase transport processes in CVD technologies in microelectronics. The transport properties (molecular diffusion coefficients, viscosity, and thermal conductivity) of pure gases and gas mixtures in the temperature range 250 to 2000 K and at a pressure < 0.1 MPa are calculated using (1) the ChapmanEnskog method in binary collision approximation and (2) the three-parameter Lennard-Jones (m-6) intermolecular potentials (IP) with 8 < m < 100 for interactions of atoms and quasi-spherical molecules, and (3) the four-parameter m-6-3 Stockmayer IP for dipole molecules. In addition to the IP parameters a ii , a jj , and a ij , the DB also supplies their variance-covariance matrix. For heavy globular molecules [such as CF 4 , SiH 4 , Si(CH 3 ) 4 , and WF 6 ], the influence of the vibrational excitation on their effective size is considered. In this case, the isotropic Lennard-Jones (m-6) IP with temperature-dependent parameters was defined. At present, the DB EPIDIF-JRB contains 40 species of importance to Si gas-phase epitaxy processes and IP parameters for 820 pair interactions. It can be used to calculate the viscosity of pure gases and gas mixtures with any k components (k < 11), and their binary diffusion coefficients, and to estimate their uncertainty as well