Reactive deposition reaction probability

This is very likely due to their very high reactivity, making deposition difficult and unwanted side reactions probable. Because the walls have uniform thickness (<1 nm), zeolites have been used as a template for the synthesis of ordered micro porous carbon materials [127-130] and they are tested for hydrogen physisorption [131]. 

U Deposition Uniformity U = fjf = f ) f) Reactant Mean Molecular Speed X Transverse Position z Normalized Transverse Position (z = x/a) a Ratio of Diffusivities P Deposition Modulus A Reactant Mean Free Path Normalized Preform Thickness p Total Molar Density o Reactive Species Molecular Diameter ( ) Reaction Probability / Net Molar Yield of Deposition Reaction... 

Often some of the lighter and more volatile species are lost in the transport between the target and the substrate or there is a less than unity reaction probability with the more condensable species on the surface of the depositing material (Sec. 11.5). This leads to a loss of stoichiometry in the deposited film compared to the target material. This loss is often made up by some degree of quasi-reactive deposition. 

Under proper conditions, films deposited by ion plating have good adhesion and good surface coverage, and are more dense than films deposited by either vacuum deposition, sputter deposition, or arc vaporization alone. Generally, it is found that concurrent bombardment increases the reaction probability therefore, the materials deposited by reactive ion plating can be made stoichiometric more easily at high deposition rates than with reactive... 

Generally, for the low temperature deposition of a compound film, one of the reacting species should be condensable and the other gaseous e.g. Ti -i- N. If both are condensable, e.g. Tl + C, the best deposition condition is to have a high substrate temperature to promote reaction, have concurrent bombardment, or use post-deposition heat treatment to react the mixture. The stoichiometry of a deposited compound can depend on the amount of reaction that occurs before the surface is buried. This depends on the amount of reactant available, the reaction probability, and the deposition rate. Reactively deposited films of oxides, carbides, nitrides, and carbonitrides are commonly used in optics, electronics, decorative, and mechanical applications. 

Activated reactive evaporation (PVD technology) Evaporation through a plasma of reactive gas in order to deposit a film of a compound material. The plasma activation increases the reaction probability and decreases the pressure of reactive gas needed to form the compound material. 

Reaction probability (reactive deposition) The probabiUty that a reactive gas species impinging on a surface will react with the surface to form a compound. The probability depends on the reactivity of the species, residence time on the surface, surface coverage, surface mobility, reaction-enhancing processes such as concurrent electron or ion bombardment, etc. 

Because the reactivity of the sediment toward sulfide and subsequent conversion of solid-phase sulfide is probably not significantly different between stations, these findings suggest that transport rather than reaction processes are predominately responsible for the observed variations in the standing crops of different forms of solid-phase sulfur and other products of decomposition in Long Island Sound (LIS) sediment. Physical and biological transport processes, which determine in part the distribution and abundance of the products or reactants of decomposition within a deposit, will now be considered. 

---