Vapor phase nucleation

Reiss, H., Tabazadeh, A., and Talbot, J. (1990) Molecular theory of vapor phase nucleation The physically consistent cluster, J. Chem. Phys. 92, 1266-1274. 

Current theories of vapor-phase nucleation usually assume homogeneous systems. Nucleation occurs in many cases under highly inhomogeneous conditions, such as in shock waves, nozzle exhausts, flames, etc. The applicability of current theories under these conditions needs careful examination [2.43]. 

Ellerby, H.M., and Reiss, H. (1992) Toward a molecular theory of vapor-phase nucleation.II. Fundamental treatment of the cluster distribution,/. Chem. Phys. 97, 5766. 

Often the process introduces contamination into the deposition system. This contamination can be associated with removable surfaces such as fixtures, with the source material, with the substrate material, or with processes related to the deposition process itself such as ultrafine particles from vapor phase nucleation of the vaporized source materials. These sources of contamination are discussed in the chapters related to the PVD process involved. 

Plasma-based PVD processing can produce ultrafine particles ( soot or black sooty crap (BSC)) in the plasma region by vapor-phase nucleation, thereby generating a dusty plasma .This is particularly true when using hydrocarbon precursors in the reactive deposition of carbides. These particles attain a negative charge and are suspended in the plasma near walls where they can grow to appreciable size. 

Vapor phase nucleation can occur in a dense vapor cloud by multibody collisions, and the nucleation can be encouraged by passing the atoms to be nucleated through a gas to provide the necessary collisions and cooling for nucleation. These particles have a size range of 10-1000 A and the size and size distribution of the particles is dependent on the gas density, gas species, evaporation rate, and geometry of the system. 

Black sooty crap (BSC) Ultrafine particles formed by vapor phase nucleation in a gaseous environment. See also Soot Ultrafine particles. 

Particle, ultrafine (cleaning) A particle of diameter less than about 0.5 micron. Generally formed by vapor phase nucleation or the residue from the evaporation of an aerosol. Also called a nanoparticle. See also Gas evaporation Nanophase materials Vapor phase nucleation. 

Vapor phase nucleation The development (condensation) of nuclei in the gas phase due to multibody collisions. See also Gas evaporation Particle, ultrafine. 

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