Bulletin of the American Physical Society
71st Annual Gaseous Electronics Conference
Volume 63, Number 10
Monday–Friday, November 5–9, 2018; Portland, Oregon
Session BM3: Plasma Diagnostics Workshop |
Hide Abstracts |
Chair: Peter Bruggeman, University of Minnesota,, Yukinori Sakiyama, Lam Research Room: Oregon Convention Center A107-A109 |
|
BM3.00001: TUTORIAL SESSION (8:00AM-12:30PM): CHAIRED BY PETER BRUGGEMAN |
Monday, November 5, 2018 8:00AM - 9:00AM |
BM3.00002: Optical Diagnostics Richard Miles Partially ionized plasmas are being applied to aerospace for flow control and combustion enhancement and to medicine for wound therapies, cancer treatment, and other procedures. These plasmas are generally localized and out of equilibrium, with the kinetic temperature much lower than the electron and vibrational temperatures. They are rapidly time varying at rates on the order of nanoseconds. Conventional probes and microwave diagnostic methods are not useful, and integrated optical methods are difficult to interpret. Important parameters are the electron density and temperature, electric field, ionization fraction, molecular vibrational and rotational temperatures, dissociated fractions, ion concentrations, chemical and radical species. All these factors change rapidly in space and time. These measurement challenges have motivated the development of spatially accurate optical diagnostics, including planar imaging methods, line imaging methods, and point measurements. The presentation will focus on methods that are most useful for the measurement of rapidly time varying, localized, partially ionized plasmas. Remaining challenges involve capturing full volumetric data at rates fast enough to follow the detailed evolution of the plasmas. [Preview Abstract] |
Monday, November 5, 2018 9:00AM - 9:30AM |
BM3.00003: BREAK (9:00AM-9:30AM) |
Monday, November 5, 2018 9:30AM - 10:30AM |
BM3.00004: Mass spectrometry of reactive low-pressure and atmospheric plasmas Jan Benedikt Reactive plasmas are highly valued for their ability to produce large amounts of reactive radicals and of energetic ions bombarding surrounding surfaces. The non-equilibrium electron driven plasma chemistry is utilized in many applications such as anisotropic etching or deposition of thin films of high-quality materials with unique properties. However, the non-equilibrium character and the high power densities make plasmas very complex and hard to understand. Mass spectrometry (MS) is a versatile diagnostic method, which has a prominent role in the characterization of reactive plasmas. It can access almost all plasma generated species: stable gas-phase products, reactive radicals, positive and negative ions or even internally excited species. It can provide absolute densities of neutral particles or energy distribution functions of energetic ions. This talk will focus on quadrupole MS with an electron impact ionization ion source as the most common MS technique applied in plasma analysis. Necessary information for the understanding of this diagnostic and its application and for the proper design and calibration procedure of an MS diagnostic system for quantitative plasma analysis will be discussed. [Preview Abstract] |
Monday, November 5, 2018 10:30AM - 11:30AM |
BM3.00005: In Situ Surface Diagnostics during Plasma-Material Interactions Vincent M Donnelly \textit{In-situ} diagnostics methods for plasma-surface interactions will be reviewed, with a focus on recombination of Cl on alumina, silica and ytttria coated surfaces during exposure to chlorine-containing inductively-coupled plasmas. Both gas-phase (optical emission and rare gas actinometry, optical absorption, and mass spectrometry) and surface diagnostics (Auger electron spectroscopy, sputter depth profiling) methods will be covered. The influence of Cl, F O and Si-containing adsorbates will be discussed. Cl loss coefficients, $\gamma_{\mathrm{Cl}}$, have been measured for a variety of plasma and surface conditions. Cl$_{\mathrm{2}}$ (i.e. recombination) and other products such as ClO and SiCl$_{\mathrm{2}}$ can be produced. Cl recombination is enhanced 1) by the presence of F, due to its electron-withdrawing effect on metal atoms, and 2) by excess oxygen that cannot coordinate to a second metal atom. Recombination appears to occur mainly by a Langmuir Hinshelwood mechanism, with perhaps added contribution by an Eley-Rideal process. $\gamma_{\mathrm{Cl}}$ is as high as 0.30 after exposure to F, and as low as 0.03 to \textless 0.001 on a SiCl$_{\mathrm{x}}$F$_{\mathrm{y}}$ surface during Si etching in a Cl$_{\mathrm{2}}$/O$_{\mathrm{2}}$ plasma. [Preview Abstract] |
Monday, November 5, 2018 11:30AM - 12:30PM |
BM3.00006: Electrical Probe Measurement Nicholas Braithwaite There are several ways to set up an electrical diagnostic-interaction with a volume of ionized gas. In one of the simpler scenarios a bare wire is inserted into a plasma and biased with respect to a convenient reference; the current-voltage characteristic of this `probe ` contains information on the electrical composition of the plasma. More generally, the electrical components of a plasma can be stimulated by DC, AC, RF/microwave electrical sources, that may in turn drive currents, provoke resonances or launch waves. The responses can be interpreted in terms of quantities such as the number densities of charged particles, the mean energies or the energy/speed distributions of charged particles and the degree of collisionality. The general `popular ` view of electrical diagnostics is that they are simple to implement but the techniques are inherently invasive and the analysis/interpretation of data is contentious. This presentation will examine the challenges of using electrical probes in a range of realistic, low-temperature plasma environments, paying due attention to achieving conditions which satisfy the assumptions that are needed to extract meaningful data from the analysis. [Preview Abstract] |
Monday, November 5, 2018 12:30PM - 2:00PM |
BM3.00007: LUNCH BREAK (12:30PM-2:00PM) |
|
BM3.00008: ADVANCES IN DIAGNOSTICS SESSION (2:00PM-5:00PM): CHAIRED BY YUKINORI SAKIYAMA |
Monday, November 5, 2018 2:00PM - 2:30PM |
BM3.00009: In situ optical diagnostics to understand plasma-surface interactions during atomic layer processing of Si-based dielectrics Sumit Agarwal The shrinking device dimensions in integrated circuits combined with the introduction of 3-D device architectures has created a need for novel atomic layer deposition (ALD) and atomic layer etching (ALE) processes for a variety of materials including Si-based dielectrics such as SiN$_{x}$ and SiO$_{\mathrm{2}}$. Development of new atomic layer processing techniques that can meet the demands for semiconductor manufacturing requires an atomistic level understanding of the surface reaction processes. In our lab, we utilize in situ optical diagnostic techniques including highly surface sensitive attenuated total reflection Fourier transform infrared spectroscopy and multi-wavelength ellipsometry to study the surface processes that occur during ALD and ALE. In this presentation, I will first discuss the low-temperature plasma-assisted ALD of SiN$_{x}$ films where one of the key challenges has been to grow conformal films in high-aspect-ratio nanostructures such that the sidewall structure and composition is the same as the top surface. In the second part of the talk, I will discuss the atomistic-level details of an SiO$_{\mathrm{2}}$ and SiN$_{x}$ ALE process consisting of CF$_{x}$ deposition from a C$_{\mathrm{4}}$F$_{\mathrm{8}}$/Ar plasma, and an Ar plasma activation step in which the CF$_{x}$ film is activated and the underlying substrates are etched. [Preview Abstract] |
Monday, November 5, 2018 2:30PM - 3:00PM |
BM3.00010: Electrical diagnostics of pulsed plasmas Tom Huiskamp, Guus Pemen In this contribution we present an overview of current and voltage diagnostics in fast transient plasmas. We explore the theoretical basis of different sensor systems and show examples of real-world implementations. Special emphasis is placed on measurement systems that can be home-made and offer a reliable and cost-effective means for fast voltage and current measurements. Additional topics include commercially available diagnostics and the calibration of sensors. Last but not least, we explore critical practical issues such as oscilloscope requirements, measurement cable requirements and electromagnetic compatibility for correct and noise-free measurements. [Preview Abstract] |
Monday, November 5, 2018 3:00PM - 3:30PM |
BM3.00011: Diagnostics of plasma-liquid interactions K. Sasaki, N. Shirai The diagnostics of plasma-liquid interactions is a more difficult task than the diagnostics of conventional plasma-solid interaction. We adopted LIF spectroscopy to an atmospheric-pressure plasma in contact with solution, where we had to be careful about the spatial distributions of the collisional quenching and the rotational temperature. We also adopted LIF to the diagnostics of laser-induced plasmas in open atmosphere with CaCl$_2$ electrolyte droplets, by which we obtained the knowledge on the production process of Ca from the CaCl$_2$ solution. In addition, laser photodetachment was applied to a dc glow discharge, where the optogalvanic effect of the laser irradiation was detected by the transient change in the discharge current. The detection of plasma-induced short-lived species in liquid is a hard subject for plasma researchers. Various methods employing chemical probes are used in our community, but they have problems in the lack of spatiotemporal resolutions. We recently adopted the chemiluminescence of luminol to the detection of short-lived species in the liquid-side of plasma-liquid interaction. We observed a thin layer with blue chemiluminescence in the region just below the plasma irradiation (N. Shirai, Y. Matsuda, and K. Sasaki, APEX \textbf{11}, 026201 (2018)). [Preview Abstract] |
Monday, November 5, 2018 3:30PM - 4:00PM |
BM3.00012: In Situ Approaches for Diagnostics of Nanoparticles in Plasmas Shurik Yatom, Alexandros Gerakis, Alexander Khrabry, Junhwi Bak, Hunter Belanger, Michael Shneider, James Mitrani, Igor Kaganovich, Andrei Khodak, Brentley Stratton, Vlad Vekselman, Yevgeny Raitses Plasmas are widely used for synthesis of various nanomaterials. Plasma-mediated methods offer industrial scale of production while being less expensive and environmentally friendly compared to chemical and mechanical methods. They also hold a promise for controllable synthesis, due to the ability to control the plasma characteristics and plasma-induced chemistry. So far, the understanding of the interplay between the plasma and the synthesized products was dependent on the ex-situ analysis and recently a demand emerges for in-situ diagnostic techniques for characterizing the nanomaterials in the gas phase. We present three different techniques for measurement of nanoparticles. Coherent Raleigh Brillouin Scattering (CRBS) relies on scattering of photons from particles trapped in a laser interference pattern. Laser-induced incandescence (LII) technique interprets the cooling pattern from the particles heated by a laser, to obtain their sizes. Laser-induced breakdown spectroscopy (LIBS) detects nanostructures and diagnoses their chemical composition. We also show examples of their application in carbon arc. [Preview Abstract] |
Monday, November 5, 2018 4:00PM - 4:30PM |
BM3.00013: Coherent and incoherent Thomson scattering in low-temperature plasmas Sedina Tsikata In laboratory plasmas, coherent Thomson scattering (CTS) and incoherent Thomson scattering (ITS) can offer insights into electron dynamics which are not readily accessible, or reliably determined, via other diagnostic techniques. In this talk, some new implementations of these tools are discussed. With coherent scattering applied to plasma thrusters and more recently, to planar magnetron studies, we are now able to link microturbulence to global measured parameters (such as discharge current) in a time-resolved way. In incoherent scattering, recently-commercialized, narrow bandstop filters for stray light removal provide new possibilities for measurement. We make use of such a component in a new ITS bench which combines compactness with a high level of sensitivity. In recent work, we have applied this diagnostic to the measurement of electron temperature, density and drift velocity in different environments: to investigate hollow cathode plasma regimes, and to obtain time-resolved electron property measurements during pulsed operation of a planar magnetron. These recent implementations of CTS and ITS provide a path forward for a fuller understanding of the physics of a range of sources. [Preview Abstract] |
Monday, November 5, 2018 4:30PM - 5:00PM |
BM3.00014: THz Diagnostics for Electron Density Measurement Uwe Czarnetzki In recent years THz spectroscopy has shown its potential as a versatile diagnostics for electron density measurements [1, 2]. The basic principle is similar to classical interferometry but there are remarkable differences that make this new diagnostics quite unique. fs-laser pulses generate, by means of a GaAs semiconductor, coherent ps pulses with a broad spectrum ranging from a few 100 GHz to a few THz. These pulses experience dispersion when passing through a plasma. By applying Fourier transformation to the detected time dependent electric field, the frequency dependent dispersion relation is directly measured. Comparison with theory yields the plasma density. The technique is insensitive to vibrations, is not affected by magnetic fields up to about one Tesla, and provides superb temporal resolution of about 100 ps. Moreover, effective parallel acquisition of the temporal plasma evolutions over adjustable periods, e.g. in the ms range, is possible with modern electroncs. The technique will be introduced and the potential for further development discussed. [1] S.M. Meier et al, JPhysD 50, 245202 (2017). [2] S.M. Meier et al, PSST 27, 035006 (2018). [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2025 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700