A simple experimental system for the determination of spatial spectroscopic optical emission

Using wavelength filtered two dimensional (2-D) optical imaging, the temporal and spatial evolution of selected excited species in a pulsed magnetron discharge has been studied. A titanium target was sputtered at a pulse frequency of 100 kHz, in an argon atmosphere, at an operating pressure of 0.27 Pa. The radial information of the emissivity was determined using the Abel inversion technique. The results show strong excitation of the observed species above the racetrack in the on-time, and the possible development of an ion-acoustic wave, initiated after the off-on transition. The on-off transition is accompanied by a burst of light from the plasma bulk consistent with the transient plasma potential reaching about +200 V. During this phase, we argue that there is a release of secondary electrons from the grounded substrate and walls due to ion bombardment, as well as an increased confinement of energetic plasma electrons. The characteristic decay times of the selected transitions at 750.4, 751.5, 810.4 and 811.5 nm (ArI), present within the bandpass width of our filters, is briefly discussed in terms of the production of fast electrons in the system.

Section: Introductionmentioning

confidence: 99%

Time resolved 2-D optical imaging of a pulsed unbalanced magnetron plasma

Bradley

Clarke

Braithwaite

et al. 2006

“…The data are then analysed by means of a reconstruction program [15,16] in order to obtain the three-dimensional spectroscopic emission profile, I (r, z), for a number of lines. Optical emission lines of N 2 , N + 2 , N, Ar and Al were studied.…”

Section: Experimental Set-upmentioning

confidence: 99%

“…In a previous work [15], we presented an experimental set-up allowing the spatial spectroscopic emission of sources with cylindrical symmetry, by the way of a recurrent adapted algorithm. It combines a fibre optic system with a monochromator coupled to a CCD camera.…”

Section: Introductionmentioning

confidence: 99%

Spatially-resolved spectroscopic optical emission of dc-magnetron sputtering discharges in argon-nitrogen gas mixtures

Debal

Wautelet

Bretagne

et al. 2000

Self Cite

The spatially-resolved spectroscopic optical emission of various lines of a dc-magnetron sputtering discharge (with cylindrical symmetry) is studied. The discharge works with an aluminium-based alloy cathode. Ar-N 2 gas mixtures are used. Emission lines corresponding to the cathode (Al) and the gas discharge species (Ar, N 2 , N + 2 , N) are considered. The three-dimensional emission profiles, I (r, z), of the lines are measured, where r is the distance from the centre of the cathode and z is the height from the cathode. I (r, z) profiles are studied as a function of the total pressure, the gas composition and the electrical power. In order to compare the results, I (r, z) profiles are fitted with an empirical analytical function. It turns out that the three-dimensional emission profiles of the various lines behave differently. The results are understood by taking into account the motion of electrons in our measured magnetic field distribution and the role of electrons in populating the upper levels of the optical transitions.

“…In most cases, the plasma emission is only measured line-integrated along the line of sight, but spatially resolved in the axial direction at one [25] or several positions [26][27][28]. Debal et al [29] presented a simple experimental system to spatially resolve the plasma volume in 3D using a set of ten optical fibres, each one positioned perpendicular to the plasma volume and distributed in the direction axial to the target. A lateral movement of the fibres enables the collection of plasma emission in the direction parallel to the target surface to finally reconstruct the radial structure of the observed line intensities using optical tomography.…”

Section: Introductionmentioning

confidence: 99%

Spatially resolved characterization of a dc magnetron plasma using optical emission spectroscopy

Ries

Bibinov

Rudolph

et al. 2018

In this work, a reactive argon−nitrogen Ar N 10 1 2 [ ( )] / dc magnetron plasma for sputtering of a chromium (Cr) target is characterized with high spatial resolution by optical emission spectroscopy (OES) using molecular nitrogen emission bands at 0.5 Pa and 100 W. Beside the global gas temperature T g , the electron temperature T e , electron density n e , and the steady-state Cr density n Cr are also determined spatially resolved using a movable OES setup inside the chamber and Abel inversion. n e and T e are found to be consistent with the values measured by a Langmuir probe (LP) within the non-magnetized region along the magnetron axis in a pure Ar plasma for the same process parameters. Finally, a nitrogen content c N of 4% in the target surface is found for the reactive plasma by matching the mean steady-state chromium density n Cr measured by OES and calculated from TRIDYN simulations.