Publications by Alan Howling | EPFL Graph Search

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Intrinsic stress measurements were carried out on hydrogenated amorphous silicon (a-Si:H) films deposited with different excitation frequencies (13.56-70 MHz), by plasma-enhanced chemical vapor deposition. It was observed that films deposited at 70 MHz have one order of magnitude smaller intrinsic stress than those deposited at 13.56 MHz. These results have been linked to the estimated variation of the ion impact energy as a function of excitation frequency, deduced from the measured variation of the peak-t

Measurements of anions and cations are reported for hydrocarbon and silane radio frequency capacitive glow discharges. Series of anions were observed by quadrupole mass spectrometry using power-modulated plasmas, and their structures are interpreted from the form of the mass spectra. Various experiments in silane plasmas show that anion confinement results in particles and conversely, anion detrapping can inhibit particle formation. In contrast, the polymerized neutral flux magnitudes, mass spectra and dyna

We study experimentally the effect of linear plasma density gradients on the self-modulation of a 400 GeV proton bunch. Results show that a positive or negative gradient increases or decreases the number of microbunches and the relative charge per microbun ...

Contamination due to particles generated and suspended in silane rf plasmas is investigated. Powder is rendered visible by illumination of the reactor volume. This simple diagnostic for global, spatio-temporal powder dynamics is used to study particle formation, trapping, and powder reduction by power modulation.

Helicon wave fundamental properties are explored experimentally and numerically in linear and toroidal geometries in the low-temperature plasma devices RAID and TORPEX. The helicon wave-plasma interaction is studied in terms of wave damping, propagation conditions in toroidal geometry, and nonlinear behavior.

In large-area radio-frequency (rf) capacitive reactors, the redistribution of rf current to maintain current continuity near asymmetric sidewalls causes a perturbation in rf plasma potential to propagate along the resistive plasma between capacitive sheath ...

In large area reactors, a local asymmetry of the electrode area, due to lateral grounded walls, causes a perturbation in rf plasma potential, due to the redistribution of lateral rf current, which propagates along the resistive plasma between capacitive sh ...

The invention relates to a method and a device for determining plasma characteristics, the method comprising the steps of: - arranging a measurement probe (2) having a self-inductance in proximity to a plasma (3) to establish inductive coupling between the ...

A birdcage resonant helicon antenna is designed, mounted, and tested in the toroidal device TORPEX. The birdcage resonant antenna is an alternative to the usual Boswell or half-helical antenna designs commonly used for ∼ 10 cm diameter helicon sources in l ...

Plasma wakefield dynamics over timescales up to 800 ps, approximately 100 plasma periods, are studied experimentally at the Advanced Wakefield Experiment (AWAKE). The development of the longitudinal wakefield amplitude driven by a self-modulated proton bun ...

In this work, the microstructure transition from amorphous to microcrystalline silicon is defined in terms of the silane concentration in the plasma as opposed to the silane concentration in the input gas flow. In situ Fourier transform infrared absorption ...

Alan Howling

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Dependence of Intrinsic Stress in Hydrogenated Amorphous-Silicon on Excitation-Frequency in a Plasma-Enhanced Chemical Vapor-Deposition Process

Anionic clusters in dusty hydrocarbon and silane plasmas

Proton Bunch Self-Modulation in Plasma with Density Gradient

Direct Visual Observation of Powder Dynamics in Rf Plasma-Assisted Deposition

Helicon Wave-Plasma Interaction in Linear and Toroidal Geometries with Birdcage Resonant Antennas

Probe measurements of plasma potential nonuniformity due to edge asymmetry in large-area radio-frequency reactors: the telegraph effect

Measurements and consequences of nonuniform radio frequency plasma potential due to surface asymmetry in large area radio frequency capacitive reactors

Method and device for determining plasma characteristics

A birdcage resonant antenna for helicon wave generation in TORPEX

Experimental study of extended timescale dynamics of a plasma wakefield driven by a self-modulated proton bunch

Uniformity of silicon microcrystallinity in large area RF capacitive reactors

Comment on "Ion energy uniformity in high-frequency capacitive discharges" [Appl. Phys. Lett. 86, 021501 (2005)]

Fast growth of microcrystalline silicon solar cells on LP-CVD ZnO in industrial KAI PECVD reactors

Plasma silane concentration as a determining factor for the transition from amorphous to microcrystalline silicon in SiH4/H-2 discharges

High growth rate deposition of hydrogenated microcrystalline Silicon by a high current DC discharge

Fourier transform infrared (FTIR) absorption spectroscopy analysis for Plasma experiments

Low frequency RF heating on TCA using Alfvén waves

Power laws for the spatial dependence of electrical parameters in the high voltage, capacitive RF sheath

Properties VHF plasmas related to technological aspects of a-Si:H deposition

Role of metastable atoms in Argon-diluted Silane RF plasmas