Surface contamination control during plasma etching

1992 ◽  
Author(s):  
Hiroshi Miyatake ◽  
K. Kawai ◽  
Nobuo Fujiwara ◽  
Masahiro Yoneda ◽  
K. Nishioka ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Surface Contamination ◽  
Contamination Control

Surface Contamination Control with Uranium Rolling Operations

AIHAJ ◽  
1959 ◽  
Vol 20 (2) ◽  
pp. 92-98 ◽  
Author(s):  
Charles D. Blackwell
Keyword(s):  
Surface Contamination ◽  
Contamination Control

scholarly journals Closer to a True Value for Heavy Metal Concentrations in Recent Antarctic Snow by Improved Contamination Control

1985 ◽  
Vol 7 ◽  
pp. 61-69 ◽  
Author(s):  
E.W. Wolff ◽  
D.A. Peel
Keyword(s):  
Surface Contamination ◽  
Anthropogenic Emissions ◽  
Natural Background ◽  
Contamination Control ◽  
Surface Samples ◽  
True Value ◽  
Time Period ◽  
Antarctic Snow ◽  
Short Time ◽  
The Antarctic

Recent snow from two sites in the Antarctic Peninsula has been analyzed for Al, Cd, Cu, Pb and Zn. Measurement of full procedural blanks and of the extent of penetration of surface contamination has allowed a rigorous appraisal of both sampling and analytical methods. Whilst the particular samples of cored firn used here have been shown to be unsuitable due to penetration of surface contamination into their interiors, surface samples collected directly into acrylic tubes showed very limited penetration of contamination. The surface samples gave the following average concentrations: Al: 0.7±0.3 ng g−1, Cd: 0.26±0.09 pg g−1, Cu: 1.9±0.5 pg g−1, Pb: 6.3±3.3 pg g−1 and Zn: 3.3±1.7 pg g−1. The Pb concentration agrees well with data from other workers for recent snow from East Antarctica, while the values for Cd, Cu and Zn are about ten times lower than have been reported previously, even for ancient Antarctic ice. Although these data refer to only one site and a short time period, it is believed that they are representative of modern Antarctic snow.The true concentrations of Cd, Cu, Pb and Zn in ancient Antarctic ice are not yet established. However the following limits are suggested for increases over natural background levels due to anthropogenic emissions: Pb 1 to 40 times, Cd 1 to 180 times, Cu 1 to 4.5 times and Zn 1 to 6 times. These results indicate that contamination may have been responsible for reports of anomalous enrichment of several heavy metals in Antarctic snow.

scholarly journals Closer to a True Value for Heavy Metal Concentrations in Recent Antarctic Snow by Improved Contamination Control

1985 ◽  
Vol 7 ◽  
pp. 61-69 ◽  
Author(s):  
E.W. Wolff ◽  
D.A. Peel
Keyword(s):  
Surface Contamination ◽  
Anthropogenic Emissions ◽  
Natural Background ◽  
Contamination Control ◽  
Surface Samples ◽  
True Value ◽  
Time Period ◽  
Antarctic Snow ◽  
Short Time ◽  
The Antarctic

Recent snow from two sites in the Antarctic Peninsula has been analyzed for Al, Cd, Cu, Pb and Zn. Measurement of full procedural blanks and of the extent of penetration of surface contamination has allowed a rigorous appraisal of both sampling and analytical methods. Whilst the particular samples of cored firn used here have been shown to be unsuitable due to penetration of surface contamination into their interiors, surface samples collected directly into acrylic tubes showed very limited penetration of contamination. The surface samples gave the following average concentrations: Al: 0.7±0.3 ng g−1, Cd: 0.26±0.09 pg g−1, Cu: 1.9±0.5 pg g−1, Pb: 6.3±3.3 pg g−1 and Zn: 3.3±1.7 pg g−1. The Pb concentration agrees well with data from other workers for recent snow from East Antarctica, while the values for Cd, Cu and Zn are about ten times lower than have been reported previously, even for ancient Antarctic ice. Although these data refer to only one site and a short time period, it is believed that they are representative of modern Antarctic snow. The true concentrations of Cd, Cu, Pb and Zn in ancient Antarctic ice are not yet established. However the following limits are suggested for increases over natural background levels due to anthropogenic emissions: Pb 1 to 40 times, Cd 1 to 180 times, Cu 1 to 4.5 times and Zn 1 to 6 times. These results indicate that contamination may have been responsible for reports of anomalous enrichment of several heavy metals in Antarctic snow.

Comparative analysis of technologies for cleaning finned bimetallic pipes of air cooling devices and methods for controlling contamination of the surface of aluminum alloys

2021 ◽  
pp. 76-78
Author(s):  
Keyword(s):  
Comparative Analysis ◽  
Aluminum Alloys ◽  
Alkaline Solution ◽  
Cold Deformation ◽  
Surface Contamination ◽  
Air Cooling ◽  
Contamination Control ◽  
Cooling Devices ◽  
Air Cooler ◽  
Energy Consuming

The results of the analysis of existing cleaning technologies for finned bimetallic pipes and methods for monitoring the contamination of the surface of aluminum alloys are presented and their disadvantages are established. It is shown that the technology used for cleaning pipes obtained by cold deformation is energy-consuming, ineffective and laborious, and the existing methods of contamination control do not provide a quantitative express assessment of the surface to be cleaned. Keywords: finning surface, contamination, cleaning, alkaline solution, finned bimetallic pipes, air cooler, control. [email protected]

Using the secondary electrons (SE) of SEM with NIST‘s MONSEL-II program to obtain improved linewidth measurements and slope angles of line edges on a MMIC GaAs device

1996 ◽  
Vol 54 ◽  
pp. 944-945
Author(s):  
Richard G. Sartore
Keyword(s):  
Integrated Circuits ◽  
Plasma Etching ◽  
Microwave Integrated Circuits ◽  
Monolithic Microwave Integrated Circuits ◽  
Thick Gold ◽  
Gaas Devices ◽  
Source Distance ◽  
Margin Of Error ◽  
Dimensional Measurements ◽  
Barrier Metal

In the evaluation of GaAs devices from the MMIC (Monolithic Microwave Integrated Circuits) program for Army applications, there was a requirement to obtain accurate linewidth measurements on the nominal 0.5 micrometer gate lengths used to fabricate these devices. Preliminary measurements indicated a significant variation (typically 10 % to 30% but could be more) in the critical dimensional measurements of the gate length, gate to source distance and gate to drain distance. Passivation introduced a margin of error, which was removed by plasma etching. Additionally, the high aspect ratio (4-5) of the thick gold (Au) conductors also introduced measurement difficulties. The final measurements were performed after the thick gold conductor was removed and only the barrier metal remained, which was approximately 250 nanometer thick platinum on GaAs substrate. The thickness was measured using the penetration voltage method. Linescan of the secondary electron signal as it scans across the gate is shown in Figure 1.

Silicon layers grown over SiO2 by liquid phase epitaxy: Electron Microscopical study

1990 ◽  
Vol 48 (4) ◽  
pp. 566-567
Author(s):  
F. Banhart ◽  
F.O. Phillipp ◽  
R. Bergmann ◽  
E. Czech ◽  
M. Konuma ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Liquid Phase ◽  
Plasma Etching ◽  
Liquid Phase Epitaxy ◽  
Three Dimensional ◽  
Microscopical Study ◽  
Sample Temperature ◽  
Structural Defects ◽  
Si Substrates ◽  
Etched Surface

Defect-free silicon layers grown on insulators (SOI) are an essential component for future three-dimensional integration of semiconductor devices. Liquid phase epitaxy (LPE) has proved to be a powerful technique to grow high quality SOI structures for devices and for basic physical research. Electron microscopy is indispensable for the development of the growth technique and reveals many interesting structural properties of these materials. Transmission and scanning electron microscopy can be applied to study growth mechanisms, structural defects, and the morphology of Si and SOI layers grown from metallic solutions of various compositions.The treatment of the Si substrates prior to the epitaxial growth described here is wet chemical etching and plasma etching with NF3 ions. At a sample temperature of 20°C the ion etched surface appeared rough (Fig. 1). Plasma etching at a sample temperature of −125°C, however, yields smooth and clean Si surfaces, and, in addition, high anisotropy (small side etching) and selectivity (low etch rate of SiO2) as shown in Fig. 2.

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