The diagnosis of electronegative magnetron plasmas

Scribbins, Steven
The diagnosis of electronegative magnetron plasmas. PhD thesis, University of Liverpool.

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The magnetron sputter tool has been employed for many years to manufacture engineering-quality thin films and coatings. While many aspects of magnetron plasmas have been extensively studied, much is still unknown. This project aims to develop a more complete picture of the magnetron sputtering plasma by performing laser-assisted electron photodetachment diagnostics to measure the density of negative ion species in these plasmas. Concentrations of negative oxygen ions were measured in oxygen/argon mixtures, and negative hydrogen ions in hydrogen discharges. Concentrations were plotted spatially across the midplane of the discharge to determine the 2-dimensional distribution of negative ions. The evolution of concentration with time is also measured. Negative ions were found to follow a spatial distribution pattern which appears to be independent of the discharge gas type, and are at maximum concentration in the diffuse region of the discharge above the magnetic field trap and off the central axis. Regions of moderately high plasma electronegativity were observed, with concentrations of negative ions exceeding the local electron density at some locations. Hydrogen discharges were shown to follow a similar pattern, however the overall proportion of negative ions within the hydrogen discharge was seen to be at lest a factor of ten lower than in the oxygen case.

Item Type: Thesis (PhD)
Additional Information: Date: 2014-09-16 (completed)
Depositing User: Symplectic Admin
Date Deposited: 26 Jan 2015 11:29
Last Modified: 17 Dec 2022 01:34
DOI: 10.17638/02005801