Rheed Observations of Silicon (100) Surface Reconstruction after Remote Hydrogen Plasma Cleaning

1989 ◽  
Vol 146 ◽  
Author(s):  
T. Hsu ◽  
L. Breaux ◽  
B. Anthony ◽  
S. Banerjee ◽  
A. Tasch
Keyword(s):  
Low Temperature ◽  
Surface Reconstruction ◽  
Silicon Surface ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Third Order ◽  
Silicon Epitaxy ◽  
The Third ◽  
Lower Temperature ◽  
Order Pattern

ABSTRACTLow temperature silicon epitaxy is critical to novel silicon-based devices requiring hyper-abrupt transitions in doping profiles or heterointerfaces. Epitaxy by Remote Plasma-Enhanced Chemical Vapor Deposition (RPCVD) consists of an in situ remote hydrogen plasma clean of the silicon surface followed by growth of silicon from silane at 220° - 400°C. Reconstruction of the silicon (100) surface from a (1×1) to a (2×1) structure after cleaning at 310°C is observed by RHEED, indicating an atomically clean surface. The removal of carbon and oxygen has been further substantiated by Auger Electron Spectroscopy (AES) and growth on these atomically clean substrates has produced good quality epitaxial films. Using remote hydrogen plasma cleans at lower temperature we report the first observation of third-order silicon surface reconstruction on a Si(100) surface, where two faint fractional order streaks between the sharp integral order streaks are observed. After a short (5 minute), low temperature (300-400 °C) anneal the third order pattern transforms rather quickly to a strong (2×1) reconstruction pattern. The third order pattern can then be restored by following the anneal with a repeat of the lower temperature hydrogen clean. Although the origin of the third order pattern is unclear at this time, we believe it is due to a Si-H complex formation at the silicon surface.

Remote Plasma-Enhanced Chemical Vapor Deposition of Epitaxial Silicon on Silicon (100) at 150°C

1989 ◽  
Vol 165 ◽  
Author(s):  
T. Hsu ◽  
B. Anthony ◽  
L. Breaux ◽  
S. Banerjee ◽  
A. Tasch
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Vapor Deposition ◽  
Hydrogen Plasma ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ex Situ ◽  
Epitaxial Silicon ◽  
Remote Plasma ◽  
Silicon Epitaxy

AbstractLow temperature processing will be an essential requirement for the device sizes, structures, and materials being considered for future integrated circuit applications. In particular, low temperature silicon epitaxy will be required for new devices and technologies utilizing three-dimensional epitaxial structures and silicon-based heterostructures. A novel technique, Remote Plasma-enhanced Chemical Vapor Deposition (RPCVD), has achieved epitaxial silicon films at a temperature as low as 150°C which is believed to be the lowest temperature to date for silicon epitaxy. The process relies on a stringent ex-situ preparation procedure, a controlled wafer loading sequence, and an in-situ remote hydrogen plasma clean of the sample surface, all of which provide a surface free of carbon, oxygen, and other contaminants. The system is constructed using ultra-high vacuum technology (10-10 Torr) to achieve and maintain contaminantion-free surfaces and films. Plasma excitation of argon is used in lieu of thermal energy to provide energetic species that dissociate silane and affect surface chemical processes. Excellent crystallinity is observed from the thin films grown at 150°C using the analytical techniques of Transmission Electron Microscopy (TEM) and Nomarski interference contrast microscopy after defect etching.

Mineral Associations of Veins with Quartz of the "Diamonds оf Donbass" Type in the Seleznevsky Coal-Bearing District (Folded Donbass)

2021 ◽  
pp. 66-72
Author(s):  
Oleg S. Krisak ◽  
Yuri V. Popov
Keyword(s):  
Low Temperature ◽  
Hydrothermal System ◽  
Third Order ◽  
Quartz Crystals ◽  
The Third ◽  
Hydrothermal Mineralization ◽  
Water Composition ◽  
Mineral Associations

The authors have established quartz and quartz-carbonate veins, the formation of which is associated with a low-temperature hydrothermal system of methane-water composition within the Seleznevsky coal-bearing region of the Folded Donbass. The article considers the features of localization of hydrothermal mineralization containing quartz with inclusions of hydrocarbons, and its potential ore content. It is established that the vein bodies are localized mainly in the near-hinge parts of the third-order brachianticlines in the central and marginal parts of the Seleznevskaya syncline. These veins form systems associated with the fracturing of the inter-layer stratification or intersecting the layers. Interplastic veins are subdivided into plate-like massive and vein-like bodies with a druze texture. The veins of the second type contain quartz crystals with hydrocarbon inclusions, referred to as "diamonds of Donbass". They form a paragenetic association with dickite. In addition, calcite in the form of short-prismatic crystals is a typical associated mineral in the vein bodies among limestone strata. In the veins among the sandstone layers, the association with goethite, oxides and hydroxides of manganese is developed. Two morphological types of cinnabar were found in the vein bodies on the basis of HMS sampling, the largest number is confined to the brachianticlines of the marginal parts of the Seleznevskaya syncline. The analysis of the results indicates the prospects for identifying mercury mineralization with quartz-dickite-cinnabar type of mineralization.

Facet Free Selective Silicon Epitaxy by Rapid Thermal Chemical Vapor Deposition

1998 ◽  
Vol 525 ◽  
Author(s):  
Katherine E. Violette ◽  
Rick Wise ◽  
Chih-Ping Chao ◽  
Sreenath Unnikrishnan
Keyword(s):  
Growth Rate ◽  
Deposition Rate ◽  
Silicon Surface ◽  
Chemical Vapor ◽  
Process Conditions ◽  
Selective Epitaxy ◽  
Silicon Epitaxy ◽  
Surface Mobility ◽  
Polysilicon Gate ◽  
Initial Stage

ABSTRACTA facet-free, selective epitaxy process has been identified using the SiH2CI2 /HCI/H2 chemistry in a commercially available, single-wafer epitaxy reactor. The pre-epitaxy bake required a minimum of 900°C in order to obtain a clean silicon surface with reasonable throughput while preserving the integrity of the shallow trench isolation structures. The epitaxy growth rate ranged from as low as 130Å/rnin at 825°C, 10 torr to as high as 1500 Å/min at 875°C and 70 torr while the deposition rate of polysilicon on polysilicon differed significantly: at 10 torr, the epitaxy growth rate is greater by as much as 50%, and at 70 torr the polysilicon deposition rate is greater by as much as 40%. The facet suppression depended heavily on two things: the undercut beneath the polysilicon gate sidewall insulator and the process pressure. The undercut is believed to be responsible for suppressing the initial stage of facet formation, most probably by completely eliminating lateral overgrowth of the crystal. The process conditions then enable continued facet suppression perhaps by restricting the silicon surface mobility. The sidewall structure and process conditions combine to make a reliably facet-free selective epitaxy process

Self-starting mode locking of a Nd:glass fiber laser by use of the third-order nonlinearity of low-temperature-grown GaAs

1999 ◽  
Vol 24 (22) ◽  
pp. 1567 ◽  
Author(s):  
M. Leitner ◽  
P. Glas ◽  
T. Sandrock ◽  
M. Wrage ◽  
G. Apostolopoulos ◽  
...  
Keyword(s):  
Low Temperature ◽  
Fiber Laser ◽  
Mode Locking ◽  
Third Order ◽  
The Third ◽  
Third Order Nonlinearity ◽  
Low Temperature Grown Gaas
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