scholarly journals Comparative analyses of plasma probe diagnostics techniques

2015 ◽  
Vol 118 (23) ◽  
pp. 233302 ◽  
Author(s):  
V. A. Godyak ◽  
B. M. Alexandrovich
Keyword(s):  
Comparative Analyses ◽  
Probe Diagnostics ◽  
Plasma Probe

Hydrocarbon Ecr Reactive Ion Etching of III-V Semiconductors with Sims Plasma Probe Diagnostics

1993 ◽  
Vol 324 ◽  
Author(s):  
Douglas L. Melville ◽  
J.G. Simmons ◽  
D.A. Thompson
Keyword(s):  
Gas Flow ◽  
Reactive Ion Etching ◽  
Microwave Cavity ◽  
Multiple Quantum ◽  
Volatile Product ◽  
Reaction Products ◽  
Dominant Group ◽  
Ion Etching ◽  
Probe Diagnostics ◽  
Plasma Probe

AbstractThe advantages of in-situ SIMS plasma probe diagnostics are highlighted in low pressure hydrocarbon ECR reactive ion etching (RIE) of III-V materials. Three aspects of the RIE process are investigated. First, the dominant ion species in a CH4/H2/Ar plasma are recorded at various chamber pressures, ECR powers, CH4/(CH4+H2) gas flow ratios and microwave cavity tuning. These studies have improved our understanding of the effects of these parameters on the relative concentrations of reactive precursor species in the plasma and have led to more rapid optimization of the etch system. Secondly, SIMS has been used for identification of reaction products from the III-V surface at the optimized plasma conditions. The Ar diluted mixture gives rise to significant levels of group V hydrides and organometallic compounds and the dominant group III volatile ions have been positively identified as dimethyl species. The third and final aspect reported is the application of volatile product identification to endpoint detection. In lcm2 multiple quantum well samples, layers as thin as 50Å are easily distinguishable.

Note: Refined possibilities for plasma probe diagnostics

2016 ◽  
Vol 87 (8) ◽  
pp. 086106 ◽  
Author(s):  
P. E. Masherov ◽  
V. A. Riaby ◽  
V. K. Abgaryan
Keyword(s):  
Probe Diagnostics ◽  
Plasma Probe

Note: The expansion of possibilities for plasma probe diagnostics

2016 ◽  
Vol 87 (5) ◽  
pp. 056104 ◽  
Author(s):  
P. E. Masherov ◽  
V. A. Riaby ◽  
V. K. Abgaryan
Keyword(s):  
Probe Diagnostics ◽  
Plasma Probe

Note: Additionally refined new possibilities of plasma probe diagnostics

2018 ◽  
Vol 89 (3) ◽  
pp. 036102
Author(s):  
V. A. Riaby ◽  
V. P. Savinov ◽  
P. E. Masherov ◽  
V. G. Yakunin
Keyword(s):  
Probe Diagnostics ◽  
Plasma Probe

scholarly journals Elevating the Precision of Plasma Probe Diagnostics by Elimination of Bare Probe Protective Shields’ Influence

2017 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Measurement Errors ◽  
Plasma Electron ◽  
Physical Analysis ◽  
Bare Metal ◽  
Langmuir Probes ◽  
Plasma Parameters ◽  
Probe Diagnostics ◽  
Plasma Probe ◽  
Shield Length ◽  
Probe Measurements

Probe diagnostics of the low pressure inductive xenon plasma were conducted using classic cylindrical Langmuir probes with conventional protection of their circuits against radio frequency interferences by bare metal shields. The dimensions of their probetips were determined in the special experiment that provided negligible local plasma distortions. Accurate probe measurements were used to determine the spatial plasma parameter distributions in a gas discharge unit of an ion thruster model which helped to develop its ion-extracting grate. The subsequent analysis of probe measurements showed that in these experiments, the plasma electron energy distribution function (EEDF) was quite noticeably deviated from the Maxwell function depending on the main probe shield length that varied from maximum to zero. Use of an additional probe in the special position where its shield was rather long with zero shield length of the main probe showed that the additional shield lowered all plasma parameters. Comparison of both probes’ data identified the principled relationship between measurement errors and EEDF distortions caused by bare probe shield and this dependence was used to correct the initial probe measurements. Therefore plasma probe diagnostics became more precise due to the lowered influence of the bare probe protective shields. Its physical analysis based on previous authors’ works showed that this effect was caused by a shortcircuited double-probe phenomenon in the bare metal shields.

Development of a Rapid Survey Method of Sampling and Analysis for Asbestos in Ambient Air

1972 ◽  
Vol 30 ◽  
pp. 630-631 ◽  
Author(s):  
R. E. Heffelfinger ◽  
C. W. Melton ◽  
D. L. Kiefer ◽  
W. M. Henry ◽  
R. J. Thompson
Keyword(s):  
Neutron Activation ◽  
Ambient Air ◽  
Survey Method ◽  
Potential Hazard ◽  
Transmission Microscopy ◽  
Comparative Analyses ◽  
Asbestos Fibers ◽  
Controlled Conditions ◽  
Unequivocal Identification ◽  
Identification And Quantification

A methodology has been developed and demonstrated which is capable of determining total amounts of asbestos fibers and fibrils in air ranging from as low as fractional nanograms per cubic meter (ng/m3) of air to several micrograms/m3. The method involves the collection of samples on an absolute filter and provides an unequivocal identification and quantification of the total asbestos contents including fibrils in the collected samples.The developed method depends on the trituration under controlled conditions to reduce the fibers to fibrils, separation of the asbestos fibrils from other collected air particulates (beneficiation), and the use of transmission microscopy for identification and quantification. Its validity has been tested by comparative analyses by neutron activation techniques. It can supply the data needed to set emissions criteria and to serve as a basis for assessing the potential hazard for asbestos pollution to the populace.

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