Plasma power variation

Plasma power variation. In Figure 19 are shown the effects of RF power on the partial pressures of silane, hydrogen, and disilane (Fig. 19a) and on the deposition rate (Fig. 19b). The total pressure is 40 Pa, and the RF frequency 50 MHz. The discharge is in the y -regime. Results are shown as a function of the supposed effective RF power, i.e., 50% of the power set at the power source. 

Finally, power variation has also been shown to affect the surface properties of the substrate (Table 1). In the case of PDMS at low power settings, plasma electron speeds are reduced and... 

Comparatively little space will therefore be devoted to some rather recent approaches, such as the plasma model of Bohm and Pines, the two-body interaction method developed by Brueckner in connection with nuclear theory, Daudel s loge theory, and the method of variation of the second-order density matrix. This does not mean that these methods would be less powerful or less impor-... 

Although there is significant local recycling near the limiter blade, it is still too weak to cause substantial poloidal variations in the plasma density and temperature profiles. The plasma flow is in a simple isothermal regime, with weak influence of atomic processes, and with the power flow to the limiter being determined by the electrostatic sheath in front of the limiter [1] (and not by atomic and molecular processes). 

Ellipsometry is probably the only easy-to-use surface analysis method which can be operated in situ and in real time. On the contrary, multiple internal reflection Fourier transform infrared spectroscopy is a very powerful technique [38] but it is rather tricky to implement. Ellipsometry allows real time studies of the surface modification during exposure to the plasma, and after the treatment. Figure 10 shows for example the variation of and A ellipsometry angles upon fluorination of Si in fluorine-based plasmas as a function of pressure and gas mixture [39], thus demonstrating the sensitivity of the technique. Infrared ellipsometry has also been used with success to investigate reaction layer composition and formation on Si in CF4-based plasmas [40,41], or to monitor patterning [42]. 

Inductively coupled plasma-atomic emission spectrometry was investigated for simultaneous multielement determinations in human urine. Emission intensities of constant, added amounts of internal reference elements were used to compensate for variations in nebulization efficiency. Spectral background and stray-light contributions were measured, and their effects were eliminated with a minicomputer-con-trolled background correction scheme. Analyte concentrations were determined by the method of additions and by reference to analytical calibration curves. Internal reference and background correction techniques provided significant improvements in accuracy. However, with the simple sample preparation procedure that was used, lack of sufficient detecting power prevented quantitative determination of normal levels of many trace elements in urine. 

Experiments to determine the effects, on the film structure and composition, of varying the plasma parameters, within moderate limits, were also carried out for the M0-C3F8 system. The range of the parameters studied was flow rate=1.7-8.3 cm3 min l (at STP), pressure=0.005-0.050 torr and power=20-100 watts. It is not appropriate, in the context of this investigation, to discuss the absolute variations of, for example, the etch and deposition rates, since this type of analysis is highly system dependent. However the most important general features, which will apply to any system, can be summarized as follows (1) while the amount of metal incorporated into the films varies within narrow limits,... 

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