Atomic oxygen films

Space-based solar ceUs are covered with a very thin layer of vitreous siHca to protect against the damaging environment of space such as atomic oxygen, micrometeorites, and radiation effects. Because the siHca is transparent to damaging uv radiation, it is normally coated with a uv-reflective thin film... 

Surface modifications and surfiice roughness Cu, Mo, and Be laser mirrors atomic oxygen modified (corroded) surfaces and films, and chemically etched surfaces. 

It was first shown in study [37] that adsorption of N-atoms on films of zinc oxide reduces its conductivity to a certain stationary value which depends, as with oxygen atoms, both on the stationary concentration of particles in the volume adjacent to the sensor s film and on the temperature. 

The influence of other active components, such as 1, OH, H on a semiconductor sensor, with other conditions being the same, is comparable with the influence of atomic oxygen [50]. Contribution of N and OH is proportional to their relative contents (compared to that of atomic oxygen) in the atmosphere and may become essential at altitudes lower than 60 - 70 km. The use of selective detectors excludes the influence of atomic hydrogen. Studies of adsorption of water vapours on ZnO films [50] show that their influence is negligibly small at the film temperatures below 100°C. Variations of electric conductivity of the films under the influence of water vapours and of an atomic oxygen are comparable at the ratio of their concentrations [H20]/[0] = 10" . 

The above conclusion was confirmed by control experiment. It is well known [47] that freshly deposited silver films are very efficient in adsorption of atomic oxygen at room temperature. Therefore, the attachment covered by Ag-film similar to that with a Co304-covering should completely stop the flux of oxygen atoms. (The experiment with the known source of oxygen atoms - hot Pt-filament - confirms the efficiency of above attachment). It occurred [44] that in case of particles leaving the Ag surface such an attachment completely shuts down the flux of particles from the surface of the sample under investigation. 

A new flame-based process is being considered to oxidize a film on a wafer. As illustrated in Fig. 17.22, a combustible mixture flows downward from a showerhead manifold onto the wafer and the exhaust products are drawn out through an annular channel. A control system is presumed to hold the wafer temperature at a fixed temperature. The objective of the process is to deliver an atomic-oxygen number density of approximately 1015 cm-3 at the wafer surface while the wafer temperature is held at approximately Tw = 320°C. Assume the following nominal process conditions showerhead-to-... 

Reaction between LB films of Cd arachidate and ground state atomic oxygen, 0(3P), was investigated at various temperatures using FTIR spectroscopy [55,56]. Intensity of the CH2 stretching infrared band was monitored in a transmission mode and was found to decrease in the course of the reaction due to disappearance of the CH2 groups. 

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