A two-dimensional (r,z) fluid model has been developed to study plasma transport in inductively coupled plasmas (ICP). Electron heating is treated by assuming a fixed, spatially varying power deposition profile in the electron energy balance equation. A high aspect ratio ICP reactor geometry has been studied, with two assumed power profiles: spatially uniform and localized to within several skin depths of the radial wall. The effect of neutral gas pressure on plasma uniformity is presented for an argon discharge over the range of 1–20 mTorr. Comparisons between the fluid model and predictions from a spatially averaged global model show similar scaling of plasma density, electron temperature, and plasma potential over a wide range of pressure and power.

In plasma immersion ion implantation, a target is immersed in a plasma and a series of negative, high-voltage pulses are applied to implant ions into the target. An approximate analytical model in one-dimensional planar geometry is developed to determine the time-varying implantation current, the total dose, and the energy distribution of the implanted ions for a voltage pulse with finite rise and fall times. Scaling rules are presented for the implanted current and energy distribution with respect to plasma density, peak applied voltage, and ion mass. Comparisons with numerical simulations are used to demonstrate that the accuracy of the model is well characterized by a single parameter: the ratio of the ion flight time to the pulse rise time.

A two-dimensional (r,z) fluid model i s used to study plasma transport in inductively coupled plasmas (IcPs). Electron heating from external t coils driven at 2 MHz is calculated self-consistently by solving for thetimeaveraged RF electric field.Radial plasma uniformity h a s been studied in both high (R/L = 2.5) and low (R/L = 1) aspect ratio ICP reactors driven with external planar or cylindrical coils. The effect of neutral gas pressure on plasma uniformity is presented for Ar discharges ai 5 and 20 mTorr. The location of extemal coils and corresponding power deposition profile is predicted to have little effect on uniformity except at higher pressure ( 2 20 mTorr) and for large aspect ratios. Planar coils appear superior to cylindrical coils for achieving relatively consistent uniformity over a wide range of pressures and reactor aspect ratios.

Ion densities, electron temperatures, plasma potentials, and absorbed powers are measured in a planar inductively coupled argon plasma source at different input powers, pressures, and aspect ratios (radius/length) and are compared to both a global (volume-averaged) model and a 2D fluid model. Qualitatively, the trends between the models and experiment are similar. Radial ion density profiles at different aspect ratios and pressures are also measured. An ion density peak offaxis is measured at a high aspectratio and predicted by the 2D fluid model.

An in-line mass spectrometer and Langmuir probes have been employed to examine mechanisms of plasma immersion hydrogen passivation of grain boundary defects in polycrystalline silicon thin film transistors. Relative fluxes of H ϩ and H 2 ϩ as well as total ion current density were measured at the substrate location in an electron cyclotron resonance hydrogen discharge. Measurements were made over a range of operating conditions over which passivation rates have been shown to vary dramatically. Data presented show a strong correlation of both H ϩ flux and ion bombardment energy with good transistor performance obtained at operating pressures below 1 mTorr. This suggests that discharge operating conditions that promote dissociation of H 2 to form H and H ϩ ͑which may diffuse more rapidly through solid material than H 2 ͒, as well as increased sheath voltages and therefore ion energy at the substrate, are important to obtaining acceptable process rates. © 1995 American Institute of Physics.Acceptable electrical performance of polysilicon thin film transistors ͑TFTs͒ for several applications, including driver circuitry for active matrix liquid crystal displays ͑AMLCD͒, requires the hydrogen passivation of defect sites in the polycrystalline silicon grain boundaries.1,2 One of the most promising methods for passivation is exposure of the fabricated transistors to low pressure ͑Ͻ1 mTorr͒ hydrogen plasmas generated in an electron cyclotron resonance ͑ECR͒ source. However, ECR-based reactors may not be well suited for large area substrate processing under development for AMLCD flat panel displays. To aid in the design of processes based on more suitable reactor types employing, for example, inductively coupled or helicon plasmas, it is helpful to understand the basic mechanisms responsible for efficient plasma exposure hydrogenation. Specifically, we address the hypothesis that high passivation rates observed in low pressure ECR hydrogen discharges are the result of enhanced dissociation of H 2 at discharge pressures below 1 mTorr.3 It is believed that because atomic hydrogen diffuses through solid material more readily than molecular hydrogen, conditions that favor a high flux of either neutral or ionized atomic hydrogen to the substrate will result in high rates of hydrogen passivation.To investigate these mechanisms, we examine plasma conditions in a H 2 ECR discharge identical to that used in a study of polysilicon passivation, over a range of operating parameters over which passivation effectiveness was found to vary dramatically.1 This study involves examination of the mass distribution and flux of ions, but not neutrals, incident on the substrate. There are practical reasons for studying only the ions, and it is believed that the ion data on its own provides substantial support for the significance of the role of atomic hydrogen. First, the presence of atomic hydrogen ions, H ϩ , can be considered to be a good indicator of the presence of neutral atomic hydrogen. In addition, even if the concentration of H ϩ ions...