Plasma generation region

In PECVD, the plasma generation region may be in the deposition chamber or precede the deposition chamber in the gas flow system. The latter configuration is called remote plasma-enhanced CVD (RPECVD). In either case, the purpose of the plasma is to give activation and partial reaction/reduction of the chemical precursor vapors so that the substrate temperature can be lowered and still obtain deposit of the same quaUty. 

Plasma treatment equipment may have the substrate in the plasma-generation region or in a remote location. A common configuration places the substrate on the driven electrode in a parallel plate rf plasma system such as is shown in Figure 1.2. When plasma treating a surface, it is important that the plasma be uniform over the surface. If this condition is not met, non-uniform treatment can occur. This is particularly important in the rf system where, if an insulating substrate does not completely cover the driven electrode, the treatment action is shorted out by the regions where the plasma is in contact with the metal electrode. To overcome this problem, a mask should be made of a dielectric material that completely covers the electrode with cutouts for the substrates. ... 

In the plasma-generation region, electrons and ions are accelerated in an electric field. At low pressures, these particles can attain high kinetic energies and may damage surfaces placed in that region. 

This can give rise to extensive heating of surfaces in the dc diode system. In the dc diode discharge configuration, the plasma-generation region is primarily near the cathode however, the plasma fills the contained volume. This plasma can be used as a source of ions for bombardment, or for activation of reactive species. 

In much plasma processing, the surface being processed is in the plasma-generation region. 

In plasma processing, the deposition conditions differ greatly, depending on whether the substrate is placed on an active electrode, in the plasma-generation region, or in a remote position where the plasma afterglow is found. 

Downstream region (plasma technology) Plasma outside the plasma generation region. See Remote plasma source Afterglow region. 

Electron cyclotron resonance (ECR) plasma source (plasma technology) A plasma source where the microwave energy, which has a resonant frequency of the electron in a magnetic field, is injected into the plasma-generating region through a dielectric window. See also Plasma source. 

Plasma-generation region The region where the electrons are accelerated to produce ions. 

Remote region (plasma) The plasma region outside the plasma-generation region where the electron energy is low. See also Afterglow Downstream region. 

However, we should mention the pioneering work of Chou and Phillips, where metallic iron and iron oxide particles were produced by injecting ferrocene into the afterglow region of a low-pressure, low-power, plasma, generated using a micro-wave power source [160]. This gas phase reaction was carried out as part of an attempt to explore the feasibility of using flow-type microwave plasmas for the production of metal nanoparticles. 

The plasma-generated gaseous species are typically in electronically excited states. Figme 2a shows a typical optical emission spectrum of the Ar plasma produced in air (10). The characteristic emission peaks from the excited Ar molecules are clearly seen in the region from 696 nm to 812 tun. The peaks at 337 nm and 674 nm originate from the excited N2 molecule (11). The peak at 309 nm is due to the OH radical produced by dissociation of water vapor in the plasma (11). The peaks at 111 nm and 845 nm are due to the excited atomic oxygen. 

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