Two-dimensional model of ion dynamics during plasma source ion implantation

Sheridan, T. E.; Alport, M. J.

doi:10.1063/1.111807

Cited by 52 publications

(27 citation statements)

References 8 publications

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“…We note that such a homogeneous plasma is often chosen as initial condition for PIII simulations. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] For a one-dimensional planar geometry, we discussed the differences between an established-sheath simulation and a homogeneous-plasma simulation in a previous article. 41 We concentrate our comparison on the time evolution of the ion current densities on the various parts of our structured surface.…”

Section: Dynamicsmentioning

confidence: 99%

“…1 However, applications of this method are usually made to complex-formed objects, such that an understanding of the processes in two-or three-dimensional sheath expansion is required. The theoretical investigation of these processes has proceeded from a fluid description [3][4][5][6][7] of the plasma to the application of various hybrid particle-in-cell [8][9][10][11][12][13][14][15][16][17] algorithms. These studies reported on a number of phenomena: The strong electrical fields around convex corners focus the ion flux into the vicinity of but not immediately onto these corners; the ion flux peak broadens and moves away from the corner in time; the region of oblique impact angle increases with time; the flux around concave corners is diminished.…”

Section: Introductionmentioning

confidence: 99%

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Simulation of sheath dynamics and current nonuniformity in plasma-immersion ion implantation of a patterned surface

Briehl

Urbassek

2003

Journal of Applied Physics

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We study the steady-state structure and the dynamics of a plasma sheath surrounding a patterned surface. A two-dimensional hybrid particle-in-cell code is employed where special attention is given to the plasma side boundaries. The surface consists of a periodic array of wide and narrow trenches. We characterize the conformity of the steady-state sheath and the uniformity of the ion currents to the wall as well as the sheath-expansion dynamics following sudden negative charging of the surface. We study the nonuniform motion of the sheath edge away from the surface, which leads to a planar high-voltage sheath. The inhomogeneous distributions of ion current and impact angle onto the walls are discussed.

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Section: Dynamicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simulation of sheath dynamics and current nonuniformity in plasma-immersion ion implantation of a patterned surface

Briehl

Urbassek

2003

Journal of Applied Physics

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“…Therefore, understanding the dynamic properties of the plasma sheath is imperative for proper control over the implantation processing. Hence, many theoretical and experimental researches have been developed to study the plasma sheath structure [21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

“…Many works have investigated the collisional and magnetized plasma sheath containing ion and electron. Besides the works studying two-component plasma sheath composed of ion and electron, the investigation of multi-component plasma sheath has recently drawn considerable attention [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. For example, experimental investigation of plasma sheath containing two positive ions can be found in Refs.…”

Section: Introductionmentioning

confidence: 99%

Magnetized plasma sheath with two positive ions where collision frequencies have a power law dependency on ions velocities

Masoudi

Khoramabadi

2015

J Theor Appl Phys

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We study the dynamics of collisional magnetized plasma sheath with two species of positive ions by using the plasma fluid model. The basic equations of the fluid model are solved numerically where the sheath is in the external magnetic field and the elastic collision between ions and neutrals has been taken into account. In our model, we assume that the collisional momentum transferring cross section has a power law dependency on ion flow velocity. Our analysis demonstrates that the sheath dynamics are sensitive to the power law dependency, especially for the ion with greater density.

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“…One-dimensional model can be used for the case of planar, cylindrical or spherical target [1,12,16,17,25] . For targets of complex shape, such as a square bar [18,19,24] , a convex or concave wedge [8] , and trench-shaped targets [20,23] , two-dimensional model should be adopted.In this paper, based on the PSII researches in our laboratory, we will simply review the theoretical studies on the ion sheath dynamics during the PSII process, which have made great progress in recent years. Concentration is focused on the various models for the calculation of ion sheath dynamics in PSII, including comparisons of these models and their applicability for different cases.…”

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confidence: 99%

Simulation methods of ion sheath dynamics in plasma source ion implantation

Wang¹

2004

Chinese Sci Bull

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Progress of the theoretical studies on the ion sheath dynamics in plasma source ion implantation (PSII) is reviewed in this paper. Several models for simulating the ion sheath dynamics in PSII are provided. The main problem of nonuniform ion implantation on the target in PSII is discussed by analyzing some calculated results. In addition, based on the relative researches in our laboratory, some calculated results of the ion sheath dynamics in PSII for inner surface modification of a cylindrical bore are presented. Finally, new ideas and tendency for future researches on ion sheath dynamics in PSII are proposed.Keywords: plasma sheath simulation, plasma source ion implantation, fluid model, particle simulation, inner surface plasma source ion implantation.Plasma source ion implantation (PSII) has been a well-known technique to modify surface properties of materials. It has many advantages over conventional ion beam implantation, i.e. it is non-line-of-sight accessible, cost-effective and it can be easily operated. In PSII, a target is immersed in a plasma. When a series of negative high-voltage ( 10 100 kV) pulses are applied to the target, ions are extracted directly from the plasma and accelerated to the target for implantation. Since the technique was proposed by Conrad in 1986 [1,2] , many experiments have performed and shown its superiorities in improving the surface hardness, the resistance to wear and corrosion of materials [3 6] .The ion dose and impact energy are the most important factors to determine the result of PSII, and the two factors depend mainly on the dynamics of ion sheath evolution. Therefore, theoretical studies on the ion sheath dynamics emerged and have been continuously developing, giving guidance for the PSII techniques. The physical model of ion sheath forming and expanding in PSII (Fig. 1) is: When a sudden negative voltage is applied to the target, initially, in the time scale of the inverse electron plasma frequency ( pe 1 ), electrons near the target are driven away, on this time scale the ion motion is negligible so that as the electrons recede, they leave behind a region of nearly uniform ion space charge around the target, which is called the "ion-matrix sheath". Subsequently, on the time scale of the inverse ion plasma frequency ( pi 1 ), ions within the sheath are accelerated into the target as they fall through the ion-matrix sheath. This, in turn, drives the sheath-plasma edge further away, exposing new ions that are extracted. Finally, on a longer time scale, the system evolves toward a steady-state Child law sheath. Fig. 1. Schematic diagram of ion sheath evolution in PSII.Based on the above physical model, before the sheath expansion, the ion density in the sheath can be assumed uniform. Thus the sheath thickness, the electric field and potential distributions within the ion-matrix sheath can be calculated by Poisson's equation [1,8 10] . During the period of sheath propagation, the ion velocity, energy, flux, dose and incidence angle at different positions of the target...

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Two-dimensional model of ion dynamics during plasma source ion implantation

Cited by 52 publications

References 8 publications

Simulation of sheath dynamics and current nonuniformity in plasma-immersion ion implantation of a patterned surface

Simulation of sheath dynamics and current nonuniformity in plasma-immersion ion implantation of a patterned surface

Magnetized plasma sheath with two positive ions where collision frequencies have a power law dependency on ions velocities

Simulation methods of ion sheath dynamics in plasma source ion implantation

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