Low-temperature Argon Plasma Research Articles

Argon plasma treatment effects on SiSiO 2 structures

Combining measurements of inversion channel I-V and high frequency C- V characteristics it is shown that argon plasma treatment leads to an increase of positive fixed oxide charge and generation of deep acceptor-type interface states (with a charge density of about 10 11 cm −2) accompanied by a reduction of the density of shallow acceptor-type interface states and a decrease of the inversion layer mobility. The radiation induced oxide charge is in the order of (1–3.5) × 10 11 cm −2 depending on the oxide thickness. The mobility decrease and the plasma-introduced charges in the Si-SiO 2 structures are assumed mainly to be trivalent Si and non-bridging oxygen due to the radiation-induced fracture of weak and strained bonds in the oxide and at the interface. The temperature behaviour of the mobility indicates a dominance of Coulomb and surface potential fluctuation scattering. Hence a severe degradation of Si-SiO 2 structures after low-temperature argon plasma treatment is found.

XPS STUDY OF SURFACE NITROGEN ON PET ACTED BY LOW TEMPERATURE PLASMA AND LOW ENERGY IONS

ESCA analysis identifies that the different functional groups of nitrogen compounds have been conbined on the PET surfaces, when modified by the air plasma and the argon plasma. In particular, the double N15 peaks occur on the PET surface after 5 minutes treatment by the low temperature argon plasma. The second peak-N15 is considered as the contribution of nitrogen oxides. The double peaks PET-N15 structure does not result by bombardment with low energy nitrogen ions and argon ions, which indicates that the effect can not be attributed to the action of low energy ion alone.

A relaxation method for determining state of equilibrium and tempera- ture ratio Te/ Tg in an argon ICPT

A relaxation method is developed which provides a sensitive means of investigating the state of equilibrium and which measures directly the temperature ratio T e/ T g, between the electrons and atomic species in an ICPT or other low temperature argon plasma. The method uses measurements of the time dependent intensities of the optically-thin argon I spectral lines immediately after removal of the plasma sustaining energy source (the rf field in the case of the ICPT). Since the intensity of the same spectral line is compared before and after the rf field switch off, which takes ≈ 3 μs, with the same plasma and the same optical system, the relaxation method is very accurate, requiring no independently measured or calculated spectroscopic parameters. Experimental results are given confirming the validity of the method for investigating the plasma and its non-equilibrium state in the argon ICPT.

UV radiation effects of argon plasma on Si−SiO 2 structures

Radiation damage is investigated in Si−SiO 2 structures with thin (34 nm) SiO 2 film exposed to the action of the ultraviolet component of a “soft” argon plasma. To obtain information about the electrical properties of the structures, inversion channel current-voltage characteristics are measured. It is found that low energy ultraviolet readiation (up to 8.7 eV) from the low-temperature argon plasma creates shallow acceptor-like interface states. As a result of the screening effect of the trapped electrons in these states a significant increase of the channel mobility is observed. It is assumed that the plasma-induced defects are connected with breaking of weak and strained bonds in the oxide and at the Si−SiO 2 interface. The temperature dependence of the channel mobility is interpreted in terms of several scattering mechanisms.

Experimental investigation of the influence of a magnetic field on the hat transfer between an argon plasma flow and the channel walls

The influence of an external transverse magnetic field on the heat transfer between a low-temperature argon plasma flow and the channel walls is experimentally investigated for Reynolds numbers in the laminar and transition regions of the flow. It is shown that the magnetic field has only a slight effect on heat transfer within the range of parameters studied. Application of a magnetic field leads to a decrease in heat transfer. From the general statements of magnetohydrodynamics, it is known [1] that an external magnetic field can have a pronounced effect on the flow of an electrically conducting medium and, in the case of ' nonisothermal flow, even on the heat transfer with the environment or with the channel walls. The nature of the influence of the magnetic field depends on various factors. The principal factors are: therelative orientation of the vectors of magnetic induction and of the mean flow rate; the flow regime; the specific characteristics of the conducting medium; the magnitude of magnetic-field induction; and the electrical conductivity of the channel walls. Theoretical and experimental investigations of heat transfer in magnetic fields are concerned mostly with flows of electrically conducting fluids (liquid metals and electrolytes) in channels. A fairly complete survey of the progress in this field is to be found in [2]. Heat transfer involved in low-temperature plasma flows in a magnetic field is characterized by such specific features as the presence of appreciable temperature and conductivity gradients both across the flow and along the channel axis, the Hall effect, and ion recombination. Methods based on approximate physical simulation of plasma flows by conducting fluids are suitable for studying heat transfer of plasma flows only within certain well established limits. Only few papers [3,4] deal with the experimental investigation of the influence of magnetic fields on the heat transfer in low-temperature plasma channel flows. These papers deal primarilywithqualitative determinations of the nature of the influence of a magnetic field in the turbulent range of Reynolds numbers. The aim of the present investigation was to determine the nature and magnitude of the influence of a transverse magnetic field on the heat transfer at the inlet section of the channel for various flow rates, various wall temperatures, and various orientations of the crosssection of a rectangular channel with respect to the magnetic field direction. The influence of a readily ionizable addition introduced into the flow on the behavior of heat transfer in the presence of an applied magnetic field is also studied. 1. The experimental equipment was composed essentially of a plasmatron, a mixing chamber, a useful channel length, a rear eham-