RF-plasma

Limitations of ECR Plasma. The limitations of ECR plasma are a more difficult process control and more costly equipment due to the added complication of the magnetic field. In addition, lower pressure (10 to 10 Torr) is required, as opposed to 0.1 to 1 Torr for RF plasma deposition, as well as the need for a high-intensity magnetic field. Since there is the added variable of the magnetic field, the processing is more difficultto control. 

An RF plasma is generated at a frequency of 13.56 MHz. A typical equipment consists ofparallel electrodes as shown inFig. 5.20. It is a cold-wall design which is used extensively forthe deposition of silicon nitride and silicon dioxide for semiconductor applications. 

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As an example, we look at tire etching of silicon in a CF plasma in more detail. Flat Si wafers are typically etched using quasi-one-dimensional homogeneous capacitively or inductively coupled RF-plasmas. The important process in tire bulk plasma is tire fonnation of fluorine atoms in collisions of CF molecules witli tire plasma electrons... 

In two other implementations of electron impact SNMS, a plasma is generated in the ionizer volume to provide an electron gas sufFiciendy dense and energetic for efficient postionization (Figure 2c). In one instrument, the electrons are a component of a low-pressure radiofrequency (RF) plasma in Ar, and in the second, the plasma is an electron beam excited plasma, also in Ar. The latter type of electron-gas SNMS is still in the developmental stages, while the former has been incorporated into commercial instmmentation. 

The SNMS instrumentation that has been most extensively applied and evaluated has been of the electron-gas type, combining ion bombardment by a separate ion beam and by direct plasma-ion bombardment, coupled with postionization by a low-pressure RF plasma. The direct bombardment electron-gas SNMS (or SNMSd) adds a distinctly different capability to the arsenal of thin-film analytical techniques, providing not only matrbe-independent quantitation, but also the excellent depth resolution available from low-energy sputterii. It is from the application of SNMSd that most of the illustrations below are selected. Little is lost in this restriction, since applications of SNMS using the separate bombardment option have been very limited to date. 

Amorphous Silicon. Amorphous silicon is generally deposited by Reaction (4) at a deposition temperature of 560°C and at low pressure (ca. 1 Torr).P l Helium RF plasma CVD is also commonly used, especially in the production of solar photovoltaic devices. 

Saitoh, H., et al., Synthesis of C-BN Film by Thermally Activated RF Plasma CVD Method, Japan New Diamond Forum, pp. 57-59, New Diamond (1988)... 

Amorphous Si3N4 powder from silicon halides and ammonia at high temperature.P lP l The powder can also be produced by using the same reaction at 1000°C in an RF plasma with a mean particle size of 0.05-0.1... 

Hussain, T., and Ibberson, V., Synthesis of Ultrafme Silicon Nitride in an RF Plasma Reactor, in Advances in Low-Temperature Plasma Chemistry, Technology, Applications, 2 71-77, (H. Boenig, ed), Technomic, Lancaster (1984)... 

Ramsey, M. E., Poindexter, E., Pelt, J. S., Marin, J., and Durbin, S. M., Hydrophobic CNx Thin Film Growth by Inductively-coupled RF Plasma Enhanced Pulsed Laser Deposition, Thin Solid Films, Vol. 360, No. 1-2,2000, pp. 82-88. 

Ortiz-Magan A.B., Pastor-Bias M.M., Eerrandiz-Gomez T.P., Morant-Zacares C., and Martfn-Martfnez J.M., 2001, Surface modifications produced by N2 and O2 RF-plasma treatment on a synthetic vulcanised rubber. Plasmas Polym., 6(1,2), 81-105. 

In addition to microwave plasma, direct current (dc) plasma [19], hot-filament [20], magnetron sputtering [21], and radiofrequency (rf) [22-24] plasmas were utilized for nanocrystalline diamond deposition. Amaratunga et al. [23, 24], using CH4/Ar rf plasma, reported that single-crystal diffraction patterns obtained from nanocrystalline diamond grains all show 111 twinning. 

Figure 1. Schematic description of the low-pressure inductively coupled rf plasma CVD system. Adapted with permission from [33], K. Okada et al., J. Mater. Res. 14, 578 (1999). 1999, Materials Research Society.

Second, in the collision term only electron-neutral collisions are considered, because RF plasmas are weakly ionized. The inelastic collisions considered are ionization, dissociation, excitation, and attachment (see also Table II). The crude... 

The variation of the IR band intensities upon nitrogen incorporation for RF plasma-deposited a-C(N) H films is shown in Figure 26, as reported by Schwan et al. [53], As mentioned before, the intensity of the C—H stretching band decreases upon nitrogen incorporation, at the same time that an increase in the N —H stretching band intensity is observed. This suggests that hydrogen preferentially... 

Mihailovic, D., Saponjic, Z., Molina, R., Puac, N., Jovancic, P., Nedeljkovic, J. and Radetic, M. (2010) Improved properties of oxygen and argon RF plasma-activated polyester fabrics loaded with Ti02 nanoparticles. ACS Applied Materials ej Interfaces, 2, 1700-1706. 

The nature of the surface of organogermanium films, obtained by magnetically enhanced rf-plasma deposition from tetraethylgermane, was examined by ESCA (electron spectroscopy for chemical analysis) and FTIR methods56. 

The O2 RIE was conducted with a RF Plasma Products Inc. reactive ion etcher. Typical etching conditions were bias voltage of -375 to -400V, 10-13 seem of O2, 10-15 mtorr pressure and 25-35 W power. 

Biro, D.A., Pleizeier, G, and Deslandes, Y. (1993b). Application of the microbond technique. IV. Improved fiber matrix adhesion by RF plasma treatment of organic fibers. J. Appl. Polym. Sci. 47. 883-894. 

By analogy, benzocyclopropene (1) is formed in low yield via biradical cycliza-tion upon irradiation of benzocyclobutenone (79), upon its flash vacuum pyrolysis, or upon pyrolysis of indan-2,3-dione (80). Reaction of phthalide 81 in a RF plasma leads also to However, these latter extrusion methods are of no preparative interest. 

Figure 8 illustrates a comparison between measured and computed rates of butadiene polymerization in an rf plasma sustained at 13.56 MHz. A perfect fit is achieved by adjusting the rate coefficients appearing in the model to the following values ... 

Szymanowski, H., Kaczmarek, M., Gazicki-Lipman, M., Klimek, L., Wozniak, B. (2005). New biodegradable material based on RF plasma modified starch. Surface and Coatings Technology, 200, 539-543. 

Ullrafine particles (UFPs) of metal and semiconductor nitrides have been synthesized by two major techniques one is the reactive gas condensation method, and the other is the chemical vapor condensation method. The former is modified from the so-called gas condensation method (or gas-evaporation method) (13), and a surrounding gas such as N2 or NII2 is used in the evaporation chamber instead of inert gases. Plasma generation has been widely adopted in order to enhance the nitridation in the particle formation process. The latter is based on the decomposition and the subsequent chemical reaction of metal chloride, carbonate, hydride, and organics used as raw materials in an appropriate reactive gas under an energetic environment formed mainly by thermal healing, radiofrequency (RF) plasma, and laser beam. Synthesis techniques are listed for every heal source for the reactive gas condensation method and for the chemical vapor condensation method in Tables 8.1.1 and 8.1.2, respectively. 

RF-Plasma Torch Reactor. A diagram of a radiofrequency (RF) plasma torch reactor (25) is shown in Figure 8.1.3. The apparatus consists of an RF-plasma reactor with frequency of 4.0 MHz, a powder feeder, a gas supply system, and an exhaust system. The torch is composed of a work coil and three concentric quartz tubes for three independent gas flows outer, inner, and center carrier gas flows. For TiN UFPs synthesis, N2 is added to the outer flow of Ar, and titanium powder sieved in advance to a size less than 25 p.m is fed into the plasma by the carrier gas of Ar... 

AIN UFPs were synthesized (27) by injecting A1 powder with NH, gas into the tail of RF-plasma generated at 13.56 MHz. Composite UFPs of Ni-TiN with dumbbell-like or dicelike morphology were produced by using Ni-Ti alloy powder as the raw material (28). 

A hybrid plasma reactor was developed for the synthesis of fine ceramic powders (59). The reactant SiCl4 was injected into a DC-arc plasma jet and decomposed completely in a hybrid plasma an RF-plasma superimposed on the DC-arc plasma. The reaction with the second reactant NH3 and/or CH4 gas, which was injected into the tail flame of the plasma, formed Si3N4 UFPs and/or Si3N4 + SiC mixed UFPs, with structures that were amorphous. 

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