Gate oxide degradation during polysilicon etching in a parallel-plate plasma-type etcher

The MMWICP (miniature microwave ICP) is a new plasma source using the induction principle. Recently Klute et al presented a mathematical model for the electromagnetic fields and power balance of the new device. In this work the electromagnetic model is coupled with a global chemistry model for nitrogen, based on the chemical reaction set of Thorsteinsson and Gudmundsson and customized for the geometry of the MMWICP. The combined model delivers a quantitative description for a non-thermal plasma at a pressure of p = 1000 Pa and a gas temperature of T g = 650-1600 K. Comparison with published experimental data shows a good agreement for the volume averaged plasma parameters at high power, for the spatial distribution of the discharge and for the microwave measurements. Furthermore, the balance of capacitive and inductive coupling in the absorbed power is analyzed. This leads to the interpretation of the discharge regime at an electron density of n e ≈ 6.4 × 10 18 m −3 as E/H-hybridmode with an capacitive and inductive component.

Section: Plasma Modelmentioning

confidence: 99%

Modelling of a miniature microwave driven nitrogen plasma jet and comparison to measurements

Klute

Kemaneci

Porteanu

et al. 2021

“…The cross sections of chemical reactions used here are adopted from the recently published studies [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. The rate coefficients of surface reactions refer to the published studies [40][41][42][43].…”

Section: Description Of the Modelmentioning

confidence: 99%

Analysis of the chemical network in a volume-production high-current negative hydrogen ion source

Wei¹,

Gao²,

Wang³

2021

Complex simulations (e.g. multi-dimensional fluid models) usually prevent the use of very large chemistry models. In this work, the important physicochemical processes in a volume-production high-current negative hydrogen ion source (HCNHIS) are identified for a pressure range of 1-100 Torr using a global model. The particle species include H 2 (υ = 0-14), H(n = 1-3), H + 3 , H + 2 , H + , H − , and electrons. The simulation results indicate that for the production of negative hydrogen ions through dissociative attachments, the high vibrational levels of hydrogen molecules are important at low pressures, and the ground state and low vibrational levels of hydrogen molecules play an increasingly important role with increasing pressure. The reactions involving the ground state, low vibrational levels, and neighboring levels of each level tend to dominate the production of vibrational levels and transitions between them in the volume-production HCNHIS. With increasing pressure, the electron energy dissipation shifts from dissociation of H 2 (υ = 0) and electron excitation of H 2 (υ = 0) through an indirect mechanism followed by radiative decay (the EV process) to electron excitation of H 2 (υ = 0) through a resonant mechanism (the eV process). A valuable subset of reactions provided by the simplified model is proposed in the investigated pressure range, which could be incorporated in more complex simulations. The results obtained with the simplified model under different simulation conditions are within an acceptable error margin of the results for the full model, which indicates that the robustness of the simplified model of chemical reactions is guaranteed to some extent.

“…The parameters are the electron temperature, the ion densities, the neutral particle density, and the plasma potential. Such models were constructed for both positive and negative ionized plasma with radio frequency and ECR discharge [42][43][44][45] and also for molecular plasma with dissociation [45]. In the field of electric propulsion, they have been used widely for estimation of thruster performance [46][47][48][49] and are a suitable way to estimate it when comparing various kinds of propellants.…”

Section: Global Model Of the Ion Sourcementioning

confidence: 99%

Water and xenon ECR ion thruster—comparison in global model and experiment

Nakagawa

Koizumi

Naito

et al. 2020

Gridded ion thrusters are one of the most commonly used types of electric propulsion, and alternative propellants have been studied for miniature ion thrusters to meet the demand of propulsion systems for micro-/nano-satellites. Water is a candidate as an alternative non-pressurized propellant for a CubeSat thruster. It is consistent with the CubeSat concept of short-term and low-cost development. In this paper, the characteristics of a miniature water ion thruster were compared with those of a xenon one using a global model and experiments. The dependence of the performance on the mass flow rate and the input microwave power was examined, and the effects of dissociation and doubly charged ions were directly measured by a quadrupole mass spectrometer. The estimates on the model were compared against experimental results for both propellants, and the performance of the thruster operating on xenon propellant was compared to the performance operating on water propellant. In the comparison between the estimates and the experimental results, the two differences were discussed: the one between water and xenon and the other from the experimental result in both cases. A performance decrease in the propellant utilization efficiency and the specific impulse cannot be avoided when using water as a propellant in an ion thruster. However, the ion production cost did not increase, and it showed the capability of water ion thruster for CubeSat application taking advantage of safety, low cost, non-pressurized system, and human-friendliness of water when used as a propellant.