Chemical vapor deposition plasma process

For this purpose, all three catalyst supports were initially synthesized by a chemical vapor deposition (CVD) process and thereafter, using a wet impregnation method, loaded with cobalt as the active component for FTS. The as-synthesized Co/nanocatalysts were then characterized by applying electron microscopic analysis as well as temperature-programmed desorption, chemi- and physisorption measurements, thermogravimetric analysis, and inductively coupled plasma... 

Chemical vapor deposition (CVD) process, 5 803-813,13 386 16 173, 531 17 209 22 129 23 7, 59 24 743-744 25 373. See also CVD entries Plasma-enhanced chemical vapor deposition (PECVD) Vapor deposition catalyzed, 26 806 ceramics and, 5 663 common precursors and corresponding thin films grown, 5 805t in compound semiconductor processing, 22 188, 189... 

In the chemical vapor deposition (CVD) process, heat is supplied through resistive heating, infrared heating, laser beam or plasma to effect a gas-phase chemical reaction involving a metal complex. The metal produced from the reaction deposits by nucleation and growth on the hot substrate which is placed in the CVD reactor. Effective reactants... 

The chemical vapor deposition (CVD) process involves the deposition of a stable solid film, produced by chemical reactions of gaseous reactants in an activated (heat, light, plasma) environment. The chemical source materials, containing elements of which the thin film is to be made, can be gaseous, liquid, or solid. ... 

Another technique proposed for the inside process is plasma chemical vapor deposition (PCVD). In this version of the process, a low-pressure plasma is generated inside the tube that does not lead to soot generation, but rather allows a heterogeneously nucleated chemical reaction to occur at the inner surface of the tube, so that the glass is built up in molecular-scale layers. This is a true chemical vapor deposition (CVD) process. More layers are required than with soot, but the process can be controlled more precisely. Unfortunately, the process has not yet proved commercially economical. 

Vacuum deposition is the deposition of a film or coating in a low pressure plasma environment. The deposition process requires increasing the mean free path for collisions of atoms and ions. In physical vapor deposition processing (PVD), for example, this ionic activity is leveraged to sputter a surface as a source of deposition material and/or bombard a polymer film to modify the film properties. Vacuum plasmas are also used to activate reactive species in deposition processes and fragment chemical precursors in plasma-enhanced chemical vapor deposition (PECVD) processes. 

In a plasma-enhanced chemical vapor deposition (PECVD) process, a substrate is exposed to one or more volatile precursors whose atoms or molecules react and/or decompose on the substrate surface, typically using hydrogen in a thermal activation to produce the required deposition. Compounds, such as oxides and nitrides, are produced in reaction with the plasma gas species, usually at lower temperature. A plasma polymerization can occur on a surface when a precursor vapor is not completely decomposed within the plasma. 

Low pressure CVD (LPCVD) (vacuum deposition processes) Chemical vapor deposition that is performed in a vacuum. Also called Sub-atmospheric CVD. See also Chemical vapor deposition Plasma-enhanced CVD (PECVD). 

Fig. 21. Schematic illustration of the four primary vapor-phase deposition processes used in optical-fiber fabrication outside vapor deposition (OVD), modified chemical vapor deposition (MCVD), plasma vapor deposition (PVD), and vapor axial deposition (VAD) (115).

Reactions of boron ttihalides that are of commercial importance are those of BCl, and to a lesser extent BBr, with gases in chemical vapor deposition (CVD). CVD of boron by reduction, of boron nitride using NH, and of boron carbide using CH on transition metals and alloys are all technically important processes (34—38). The CVD process is normally supported by heating or by plasma formed by an arc or discharge (39,40). 

Chemical vapor deposition is a synthesis process in which the chemical constituents react in the vapor phase near or on a heated substrate to form a solid deposit. The CVD technology combines several scientific and engineering disciplines including thermodynamics, plasma physics, kinetics, fluid dynamics, and of course chemistry. In this chapter, the fundamental aspects of these disciplines and their relationship will be examined as they relate to CVD. 

Inside" processes—such as modified chemical vapor deposition (MCVD) and plasma chemical vapor deposition (PCVD)—deposit doped silica on the interior surface of a fused silica tube. In MCVD, the oxidation of the halide reactants is initiated by a flame that heats the outside of the tube (Figure 4.8). In PCVD, the reaction is initiated by a microwave plasma. More than a hundred different layers with different refractive indexes (a function of glass composition) may be deposited by either process before the tube is collapsed to form a glass rod. 

The U.S. electronics industry appears to be ahead of, or on a par with, Japanese industry in most areas of current techniques for the deposition and processing of thin films—chemical vapor deposition (CVD), MOCVD, and MBE. There are differences in some areas, thongh, that may be cracial to future technologies. For example, the Japanese effort in low-pressure microwave plasma research is impressive and surpasses the U.S. effort in some respects. The Japanese are ahead of their U.S. counterparts in the design and manufacture of deposition equipment as well. 

---