ion minority mncentrations in a w e d y ionized hydrogen plasma are determined through the comparison between the measured wavelength of the neutralized ion Bernstein waves and the theoretical one, given by the solution of the complete electrostatic dispersion relation. A simple model based on the resolution of fluid balance equations permits us to explain the presence of a high percentage of H:The presence of ion impurities' in weakly ionized plasmas is important for explaining the results of various nonlinear plasma-wave experiments, such as parametric decay (Ono et a1 1980) and soliton propagation (Pierre ef a1 1985).
This article describes the use of Langmuir probes to measure plasma parameters in low density, low temperature plasmas with a strong applied magnetic field. The experiment has been performed at the Physics Department of Milan’s University on the steady-state toroidal machine “Thorello.” Results have been analyzed by taking into account instrumental and ionic sheath effects. Finally, experimental results have been compared with direct measurements of the electron distribution function in Thorello.
AbStiiCt-Elect~ostatic wave propagation transverse to a magnetic field B is analyzed in the range of the ion cyclotron frequency in a toroidal device. The clmtrostatic ion cyclotron waves are excited by means of an electromagnetic signal injected through an antenna system located in the centre of the plasma. For the first time the backward mode is detected in hydrogen and deuterium plasmas. A comparison between the theoretical dispersion relation and the experimental results permits an indirect accurate estimate of the ion temperature, typically in the range 0.054.3 eV.
This paper describes for the first time a methodology which allows direct correlation between charging potential, measured in actual process condition using Flash Memory cell as charging sensor, and "latent" oxide damage revealed through FN injection on transistors. The methodology was used to study charging effects in a TCP metal etcher with actual process conditions, as function of antenna shape. SignlJicant 7th shifts after FN injection were found only with very dense 'Ifinger" antennas, revealing enhanced oxide damage due to the "electron shading" effects. The oxide damage is strictly correlated with the charging potential measured with Flash Memory cells having the same antenna structures as transistors.
INTRODUCTIONThe electron shading damage mechanism as proposed by Hashimoto (1-3) has been widely accepted as the major charge damage mechanism for the current device generation. Vahedi et a1 (4) derived an analytic model that clarifies the contribution of plasma and device parameters in topography induced charging. The effects predicted by the analytic model have been verified by our previous work (5).This continuation of the work examines the role of plasma parameters on V,h-shifts in transistors fabricated with a Flash memory process where metal 1 (Ml) was etched in a Lam TCPTM 9600PTX chamber. The roles of low pressure, RF bias, and pulsed plasmas in reducing damage were investigated using these antenna device wafers. Initial results appeared to contradict analytic mode predictions, but investigation of the topography changes during etch eliminated the contradictions and is leading to work on a refined analytic model taking dynamic effects into consideration.
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