Loss of Oxygen Atoms on Well-Oxidized Cobalt by Heterogeneous Surface Recombination

Abstract

Calorimetry is a commonly used method in plasma characterization, but the accuracy of the method is tied to the accuracy of the recombination coefficient, which in turn depends on a number of surface effects. Surface effects also govern the kinetics in advanced methods such as atomic layer oxidation of inorganic materials and functionalization of organic materials. The flux of the reactive oxygen atoms for the controlled oxidation of such materials depends on the recombination coefficient of materials placed into the reaction chamber, which in turn depends on the surface morphology, temperature, and pressure in the processing chamber. The recombination coefficient of a well-oxidized cobalt surface was studied systematically in a range of temperatures from 300 to 800 K and pressures from 40 to 200 Pa. The coefficient increased monotonously with decreasing pressure and increasing temperature. The lowest value was about 0.05, and the highest was about 0.30. These values were measured for cobalt foils previously oxidized with oxygen plasma at the temperature of 1300 K. The oxidation caused a rich morphology with an average roughness as deduced from atomic force images of 0.9 µm. The results were compared with literature data, and the discrepancy between results reported by different authors was explained by taking into account the peculiarities of their experimental conditions.

The penetration depth of atomic radicals in tubes with catalytic surface properties

“…The results in tables 1-3 do not allow for drawing the pressure dependence, because different authors used different experimental setups and different methods for the determination of the atom loss coefficient. Still, some recent studies reported that the atom loss coefficient for some materials decreases with increasing pressure [49][50][51]. The pressure dependence of the atom loss coefficient for oxygen atoms on nickel and cobalt was studied systematically previously, and the results were published recently [52,53].…”

Evolution of the Surface Wettability of Vertically Oriented Multilayer Graphene Sheets Deposited by Plasma Technology

“…The dense plasma enabled substantial dissociation of oxygen or the propane precursor and the partial ionization of atoms and propane molecular fragments. The dissociation fraction of oxygen was determined with a calibrated catalytic probe, as explained in detail elsewhere [ 29 ].…”

Kinetics of Surface Wettability of Aromatic Polymers (PET, PS, PEEK, and PPS) upon Treatment with Neutral Oxygen Atoms from Non-Equilibrium Oxygen Plasma

“…The absolute inaccuracy of the catalytic probe i around 20% in the probing range between approximately 3 × 10 18 and 3 × 10 21 m −3 . Detail about the probe calibration and catalytic properties of the cobalt probes have been pro vided elsewhere [33]. The treatment chamber is shown in Figure 3.…”