Micron-focused ion beamlets

Chowdhury, Abhishek; Bhattacharjee, Sudeep

doi:10.1063/1.3371688

Cited by 10 publications

(6 citation statements)

References 24 publications

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“…This arrangement provides the required field for resonance heating as well as confines the plasma due to the minimum B-field at the center of MC. [30][31][32][33] To slow down the fast electrons produced in the production chamber, a magnetic filter is introduced in between the two chambers which forms the intermediate region. Rectangular magnets are placed transversely such that the opposite polarities face each other, generating a transverse magnetic field perpendicular to the flow of plasma electrons ( Fig.…”

Section: Experimental Set-upmentioning

confidence: 99%

Utilizing upper hybrid resonance for high density plasma production and negative ion generation in a downstream region

Sahu¹,

Bhattacharjee²

2012

Journal of Applied Physics

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Localized wave-induced resonances are created by microwaves launched directly into a multicusp (MC) plasma device in the k ⊥ B mode, where k is the wave vector and B is the static magnetic field. The resonance zone is identified as upper hybrid resonance (UHR), and lies r = ∼22 mm away from the MC boundary. Measurement of radial wave electric field intensity confirms the right hand cutoff of the wave (r = 22.5–32.1 mm) located near the UHR zone. A sharp rise in the corresponding electron temperature in the resonance region by ∼13 eV from its value away from resonance at r = 0, is favorable for the generation of vibrationally excited molecules of hydrogen. A transverse magnetic filter allows cold electrons (∼1–2 eV) to pass into the downstream region where they generate negative ions by dissociative attachment. Measurements of electron energy distribution function (EEDF) support the viewpoint. H− current density of ∼0.26 mA/cm2 is obtained at a wave power density of ∼3 W/cm2 at 2.0 mTorr pressure, which agrees reasonably well with results obtained from a steady state model using particle balance equations.

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Section: Experimental Set-upmentioning

confidence: 99%

Utilizing upper hybrid resonance for high density plasma production and negative ion generation in a downstream region

Sahu¹,

Bhattacharjee²

2012

Journal of Applied Physics

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“…Space charge is estimated to be negligible in the droplet mode. An ion trajectory code11–13 is used to predict the electric field distribution described by the Laplace equation for potential V [Equation (2)] and the trajectories described by Newton's laws. ${\vec {F}}$ is the Lorentz force, ${\vec {E}}$ the electric field, ${\vec {B}}$ the magnetic field (zero in our case), q the electric charge of the particle and ${\vec {v}}$ is the instantaneous velocity of the particle [Equation (3)].…”

Section: Theory and General Governing Equationsmentioning

confidence: 99%

Multi‐Scale Investigation of a Colloid Micro‐Propulsion System

Morris

Forget

Malardier-Jugroot

et al. 2011

Plasma Processes & Polymers

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IntroductionElectric propulsion is an advanced form of spacecraft propulsion which has many advantages over traditional counterparts. This propulsion device can be useful for satellites for the purpose of station-keeping, attitude control and possibly de-orbiting at end-of-life to reduce space debris. Advanced electric propulsion has also been demonstrated to be highly efficient for both commercial and military satellites. Indeed, electrostatic propulsion exhibits high specific impulse. i.e., exhaust velocity is very high. The thrust is relatively small but the combined effect of an electric propulsion system leads to significant reductions in propellant usage and enhanced lifetime. To illustrate, a relatively small force kept constant for a long period of time produces a relatively large velocity over time. The Tsiolkovsky equation encapsulates the advantages of electric propulsion: Dv ¼ v e lnðm i =m f Þ; where Dv is the change in velocity of the spacecraft, v e the mass-averaged value of the propellant exhaust velocity and m i and m f are the spacecraft masses before and after the thrusting event, respectively. It is clear from this equation that ambitious missions (i.e., for substantial changes in vehicle velocity), will necessitate a very large initial to final vehicle mass ratio

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“…10. As the voltage between the PE and the collector determines the focal point of the beam, 11 we determined the spot size in a view to locate the focal point on the substrate by adjusting the extraction voltage. The irradiated regions of the samples show higher value of sheet resistance than the pristine one and has been confirmed from the micron-scale resistivity measurement with the help of the circuit fabricated as shown in Fig.…”

Section: Aip Advances 4 127127 (2014)mentioning

confidence: 99%

“…A MIBS 10,11 has been developed to investigate interaction of low energy (1 -5 keV) ion beams with different substrate materials at micrometer resolutions. A compact microwave driven plasma (ion) source developed in the laboratory is employed to obtain the beamlets.…”

Section: Introductionmentioning

confidence: 99%

Stopping potential and ion beamlet control for micro-resistive patterning through sub-Debye length plasma apertures

et al. 2014

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Focused multiple ion beamlets from a microwave plasma source is investigated for localized micron-scale modification of substrates in a patterned manner. Plasma electrodes (PE) with an array of through apertures having aperture diameters of the order of plasma Debye length are investigated for generating the beamlets. Extraction through sub-Debye length apertures becomes possible when the PE is kept at floating potential. It is found that the current – voltage characteristics of the extracted beamlets exhibits interesting features such as a space-charge-limited region that has a different behaviour than the conventional Child-Langmuir’s law and an extraction-voltage-limited region that does not undergo saturation but exhibits a Schottky-like behaviour similar to that of a vacuum diode. A switching technique to control the motion of individual beamlets is developed and the stopping potential determined. The beamlets are thereafter used to create localized micro-resistive patterns. The experimental results are compared with simulations and reasonably good agreement is obtained.

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Micron-focused ion beamlets

Cited by 10 publications

References 24 publications

Utilizing upper hybrid resonance for high density plasma production and negative ion generation in a downstream region

Utilizing upper hybrid resonance for high density plasma production and negative ion generation in a downstream region

Multi‐Scale Investigation of a Colloid Micro‐Propulsion System

Stopping potential and ion beamlet control for micro-resistive patterning through sub-Debye length plasma apertures

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