Process and Surface Characterization of Hydrogen Plasma Cleaning of Si(100)

1990 ◽  
Vol 204 ◽  
Author(s):  
T. P. Schneider ◽  
J. Cho ◽  
J. Vander Weide ◽  
S.E. Wells ◽  
G. Lucovsky ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Hydrogen Plasma ◽  
Surface States ◽  
Diagnostic Techniques ◽  
Gas Analysis ◽  
Plasma Cleaning ◽  
Low Energy Electron ◽  
Diffraction Patterns ◽  
Surface Diffraction

ABSTRACTThis study details low pressure and low temperature cleaning of Si(100) surfaces. The properties of Si surfaces exposed to variations in plasma generated H are described. The diagnostic techniques used to study the processing conditions are residual gas analysis (RGA) and emission spectroscopy. The surface is characterized by low energy electron diffraction (LEED) and angle resolved uv-photoemission spectroscopy (ARUPS). During the cleaning, Si complexes are formed which indicates the removal of species from the Si(100) surface. Plasma cleaning at 300°C results in a Si(100) surface with 2×1 surface diffraction patterns as detected by LEED. Measurements by ARUPS with He I radiation show the absence of Si surface states on the Hpassivated surface. The ARUPS measurements also indicate that the H begins to desorb from the Si(100) H-passivated surface at ∼500°C.

Low Temperature Hydrogen Plasma Cleaning Processes of Si (100), Ge (100), and SixGe1−x (100)

1991 ◽  
Vol 220 ◽  
Author(s):  
T. P. Schneider ◽  
D. A. Aldrich ◽  
J. Cho ◽  
R. J. Nemanich
Keyword(s):  
Low Temperature ◽  
Hydrogen Plasma ◽  
Electronic States ◽  
Gas Analysis ◽  
Process Conditions ◽  
Processing Temperature ◽  
Plasma Cleaning ◽  
Diffraction Patterns ◽  
Uv Ozone

ABSTRACTWet chemical and in situ hydrogen plasma cleaning processes were studied and a low temperature cleaning process was developed for Si (100), Ge (100) and SixGe1−x (100) surfaces. A uv-ozone and HF based spin etch were used to initially remove contaminants and oxides from the Si (100) and SixGe1−x (100) surfaces. The Ge (100) surfaces were treated with deionized water prior to entry to UHV. Residual gas analysis (RGA) was used in the investigation of the surface removal process of the in situ H-plasma cleaning. Low Energy Electron Diffraction (LEED) and angle resolved UV-Photoemission Spectroscopy (ARUPS) were used to examine the surface structure and electronic states. The 2×1 LEED patterns were obtained for Si (100), Ge (100) and SixGe1−x (100) after cleaning at a maximum processing temperature of 300°C. By varying process conditions, the LEED showed the 1×1 and 2×1 surface diffraction patterns. The ARUPS spectra showed the electronic states and the chemistry of the cleaned surfaces.

Surface Characterization of Carbon-Bearing Magnetite (CBM) and Carbon-Bearing Ni(II)-Ferrite (CBNF)

1994 ◽  
Vol 344 ◽  
Author(s):  
T. Sano ◽  
K. Akanuma ◽  
M. Tsuji ◽  
Y. Tamaura
Keyword(s):  
Photoelectron Spectroscopy ◽  
Spinel Structure ◽  
Surface Characterization ◽  
Carbon Deposition ◽  
X Ray Diffraction ◽  
Xps Spectra ◽  
X Ray ◽  
Oxygen Ions ◽  
Diffraction Patterns

AbstractOxygen-deficient magnetite (ODM; Fe3O4-δ, δ>0) synthesized by reduction of magnetite with H2 at 300°C decomposed CO2 to carbon with an efficiency of nearly 100% at 300°C. In this reaction, two oxygen ions of the CO2 were incorporated into the spinel structure of ODM and carbon was deposited on the surface of ODM with zero valence to form visible particles. The particles of carbon separated from ODM were studied by Raman, energy-dispersive X-ray and wave-dispersive X-ray spectroscopies. The carbon which had been deposited on the ODM was found to be a mixture of graphite and amorphous carbon in at least two levels of crystallization. X-ray photoelectron spectroscopy and X-ray diffraction patterns of the carbon-bearing magnetite (CBM) showed no indication of carbide (Fe3C) or metallic iron (α-Fe) phase formation. In the C 1s XPS spectra of the CBM, no peaks were observed which could be assigned to CO2 or CO. X-ray diffractometry, chemical analysis and TG-MS measurement showed that the carbon-bearing Ni(II)-ferrite (CBNF) (Ni(II)/Fetotal = 0.15) synthesized by the carbon deposition reaction from CO2 with the H2-reduced Ni(II)-ferrite was represented by (Ni0.28Fe2.72O4.00)1-δ (Ni2+06.9Fe2+2.31O3.00)δCτ (δ= 0.27, τ= 0.17). The carbon of the CBNF gave the CIOlayer-like oxide containing some Ni2+ ions.

Characterization of a slot antenna microwave plasma source for hydrogen plasma cleaning

1995 ◽  
Vol 13 (4) ◽  
pp. 2074-2085 ◽  
Author(s):  
D. Korzec ◽  
F. Werner ◽  
A. Brockhaus ◽  
J. Engemann ◽  
T. P. Schneider ◽  
...  
Keyword(s):  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Plasma Source ◽  
Slot Antenna ◽  
Plasma Cleaning

scholarly journals Optical Features of Nanosize Iron and Molybdenum Sulfide Clusters

1994 ◽  
Vol 358 ◽  
Author(s):  
J. P. Wilcoxon ◽  
G. Samara ◽  
P. Newcomer
Keyword(s):  
Surface Characterization ◽  
Surface States ◽  
Molybdenum Sulfide ◽  
Narrow Bandgap ◽  
Sulfide Clusters ◽  
Optical Applications ◽  
Bandgap Semiconductors ◽  
Large Clusters ◽  
Small Clusters

ABSTRACTIn the bulk state FeS2 and MoS2 are optically opaque, narrow bandgap semiconductors with no optical applications. We demonstrate that nanosize FeS2 and MoS2 have bandgaps that can be adjusted to the visible and even UV region of the spectrum by control of the cluster size. This opens up a host of applications of these materials as inexpensive solar photocatalysts. We demonstrate that the band-gap of both materials shifts to the blue with decreasing size but ceases shifting when a size of ∼ 3 nm (in the case of MoS2) is attained. We interpret this observation as a change from bulk quantum confinement of the hole-electron pair of a tiny semiconductor to a set of discrete molecular-like transitions more characteristic of a large molecule. Room temperature photoemission studies of these clusters demonstrate that, while photoemission shifts to the blue with increasing bandgap for large clusters, small clusters have photoemission exclusively from trapped sub-bandgap surface states. Chemical modification of the surface to introduce hole or electron traps can result in either an enhancement or a decrease in the photoluminescence. In addition, we report our results concerning chemical purification and preliminary surface characterization of MoS2 clusters by chromatography.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Zero-loss omega-filtered REM and RHEED on the new Zeiss 912

1991 ◽  
Vol 49 ◽  
pp. 616-617
Author(s):  
J.C.H. Spence ◽  
J. Mayer
Keyword(s):  
Electron Microscopy ◽  
Materials Science ◽  
Surface States ◽  
Ccd Camera ◽  
Dark Field ◽  
Ion Pump ◽  
Magnetic Imaging ◽  
Reflection Electron Microscopy ◽  
Diffraction Patterns ◽  
Large Background

The Zeiss 912 is a new fully digital, side-entry, 120 Kv TEM/STEM instrument for materials science, fitted with an omega magnetic imaging energy filter. Pumping is by turbopump and ion pump. The magnetic imaging filter allows energy-filtered images or diffraction patterns to be recorded without scanning using efficient parallel (area) detection. The energy loss intensity distribution may also be displayed on the screen, and recorded by scanning it over the PMT supplied. If a CCD camera is fitted and suitable new software developed, “parallel ELS” recording results. For large fields of view, filtered images can be recorded much more efficiently than by Scanning Reflection Electron Microscopy, and the large background of inelastic scattering removed. We have therefore evaluated the 912 for REM and RHEED applications. Causes of streaking and resonance in RHEED patterns are being studied, and a more quantitative analysis of CBRED patterns may be possible. Dark field band-gap REM imaging of surface states may also be possible.

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