Thermal Decomposition of CeO$_{\bf 2}$ in Ultra High Vacuum as a Cause of Polycrystalline Growth of Si Films on Epitaxial CeO$_{\bf 2}$/Si

1997 ◽  
Vol 36 (Part 2, No. 2A) ◽  
pp. L133-L135 ◽  
Author(s):  
Yasuhiro Yamamoto ◽  
Satoshi Arai ◽  
Taketo Matsuda ◽  
Masataka Satoh ◽  
Tomoyasu Inoue
Keyword(s):  
Thermal Decomposition ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Si Films

Thermodynamic Modelling of Ultra-high Vacuum Thermal Decomposition for Lunar Resource Processing

2021 ◽  
pp. 105272
Author(s):  
Matthew G. Shaw ◽  
Geoffrey A. Brooks ◽  
M. Akbar Rhamdhani ◽  
Alan R. Duffy ◽  
Mark I. Pownceby
Keyword(s):  
Thermal Decomposition ◽  
High Vacuum ◽  
Thermodynamic Modelling ◽  
Ultra High Vacuum

High-Quality a-Si-Based Alloys : a-SiGe Films Fabricated in a Super Chamber and Superlattice Structure a-Si Films Prepared by a Photo-CVD Method

1987 ◽  
Vol 95 ◽  
Author(s):  
Shinya Tsuda ◽  
Hisao Haku ◽  
Hisaki Tarui ◽  
Takao Matsuyama ◽  
Katsunobu Sayama ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Photovoltaic Effect ◽  
High Vacuum ◽  
Reaction Chamber ◽  
Wide Bandgap ◽  
Ultra High Vacuum ◽  
High Quality ◽  
Cvd Method ◽  
Superlattice Structure ◽  
Si Films

AbstractIn order to improve the conversion efficiency of a-Si solar cells, high-quality a-Si based alloys of both narrow handgap and wide bandgap were studied.Concerning the narrow bandgap material, we found a particular dependence of film qualities on substrate temperature. In addition, high-quality a-SiGe:H films were obtained by using a super chamber (separated ultra-high vacuum reaction chamber).As for the high-quality wide bandgap material, a-Si/a-SiC superlattice structure films fabricated by a photo-CVD method were studied for the first time. From the analysis of their properties, we found that the superlattice structure p-layer was an active layer for photovoltaic effect. A conversion efficiency of 11.2% has been obtained for a pin a-Si solar cell whose player was of the superlattice structure.

High Temperature Reproducible Preparation of Mg2Si Films on (001)Al2O3 substrates Using RF Magnetron Sputtering Method

2014 ◽  
Vol 1642 ◽  
Author(s):  
Atsuo Katagiri ◽  
Shota Ogawa ◽  
Takao Shimizu ◽  
Masaaki Matsushima ◽  
Kensuke Akiyama ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Single Phase ◽  
High Vacuum ◽  
Stoichiometric Composition ◽  
Target Surface ◽  
Rf Magnetron Sputtering ◽  
Area Ratio ◽  
Ultra High Vacuum ◽  
Process Window ◽  
Si Films

ABSTRACTA RF magnetron sputtering method was used to prepare Mg2Si films at 300-400oC on (001) Al2O3 substrates from a Mg disc target with Si chips. Mg deposition was not detected at 400°C from a pure Mg disc target without Si chips due to the high vapor pressure of Mg. However, the amount of Mg deposition increased with the increase in Si/(Mg+Si) area ratio of the target surface together with the increase of the Si deposition. The obtained films had a stoichiometric composition of Si/(Mg+Si)=0.33 that consisted of the well crystalline Mg2Si single phase regardless of Si/(Mg+Si) area ratio of the target surface. This showed the existence of a “process window” against supply ratio of Si/(Mg+Si) for Mg2Si single phase films with a stoichiometric composition. This is considered to be due to the vaporization of the excess Mg prepared under the Mg excess condition as reported by Mahan et al. for Mg2Si films prepared at 200°C by ultra-high vacuum evaporation.

Polymerization of C-Si Films on Metal Substrates: Potential Adhesion/Diffusion Barriers for Microelectronics

1998 ◽  
Vol 511 ◽  
Author(s):  
Li Chen ◽  
J. A. Kelber
Keyword(s):  
High Vacuum ◽  
Temperature Programmed Desorption ◽  
Diffusion Barriers ◽  
Ultra High Vacuum ◽  
Polymeric Films ◽  
Vinyl Silane ◽  
Cu Substrates ◽  
Auger Spectra ◽  
Temperature Programmed ◽  
Si Films

ABSTRACTCarbon-Silicon polymeric films have been formed by electron beam bombardment (500eV) of molecularly adsorbed vinyl silane precursors under ultra-high vacuum (UHV) conditions. Temperature programmed desorption (TPD) studies show that polymerization is occurring via the vinyl groups, while Auger spectra show that the polymerized films have compositions very similar to the starting precursors; vinyltrichlorosilane (VTCS) or vinyltrimethylsilane(VTMS). VTCSderived films ˜ 100 Å thick show no reaction with Cu substrates and no diffusion of Cu until temperatures greater than 700 K, while Cu deposited on VTMS films on Al substrates show no diffusion prior to Al reaction/decomposition at 600 K. Auger and TPD studies also show that fluorocarbon precursors, such as perfluorobenzene can be incorporated into the films by e-beaminduced reactions, a first step in the controlled growth of adherent polymer films on unreactive substrates such as Cu.

Preparation and Properties of High-Quality a-Si Films with a Super Chamber : Separated Ultra-High Vacuum Reaction Chamber

1987 ◽  
Vol 26 (Part 1, No. 1) ◽  
pp. 33-38 ◽  
Author(s):  
Shinya Tsuda ◽  
Tsuyoshi Takahama ◽  
Masao Isomura ◽  
Hisaki Tarui ◽  
Yukio Nakashima ◽  
...  
Keyword(s):  
High Vacuum ◽  
Reaction Chamber ◽  
Ultra High Vacuum ◽  
High Quality ◽  
Si Films

Thin Pyrolytic Graphite Films for Electron Microscope Substrates

1971 ◽  
Vol 29 ◽  
pp. 226-227 ◽  
Author(s):  
George H. N. Riddle ◽  
Benjamin M. Siegel
Keyword(s):  
Vacuum Chamber ◽  
Pyrolytic Graphite ◽  
High Vacuum ◽  
Dark Field ◽  
Ultra High Vacuum ◽  
Graphite Substrate ◽  
Nickel Substrate ◽  
Routine Procedure ◽  
Field Electron Microscopy ◽  
Dark Field Electron

A routine procedure for growing very thin graphite substrate films has been developed. The films are grown pyrolytically in an ultra-high vacuum chamber by exposing (111) epitaxial nickel films to carbon monoxide gas. The nickel serves as a catalyst for the disproportionation of CO through the reaction 2C0 → C + CO2. The nickel catalyst is prepared by evaporation onto artificial mica at 400°C and annealing for 1/2 hour at 600°C in vacuum. Exposure of the annealed nickel to 1 torr CO for 3 hours at 500°C results in the growth of very thin continuous graphite films. The graphite is stripped from its nickel substrate in acid and mounted on holey formvar support films for use as specimen substrates.The graphite films, self-supporting over formvar holes up to five microns in diameter, have been studied by bright and dark field electron microscopy, by electron diffraction, and have been shadowed to reveal their topography and thickness. The films consist of individual crystallites typically a micron across with their basal planes parallel to the surface but oriented in different, apparently random directions about the normal to the basal plane.

A High Voltage Electron Microscopy Study of Sub-Oxide Formation in Vanadium

1971 ◽  
Vol 29 ◽  
pp. 212-213
Author(s):  
R. H. Geiss ◽  
R. L. Ladd ◽  
K. R. Lawless
Keyword(s):  
High Vacuum ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Ultra High Vacuum ◽  
Pure Oxygen ◽  
Pressure Oxidation ◽  
High Voltage Electron Microscopy ◽  
Oxidation Study ◽  
Voltage Electron ◽  
Good Agreement

Detailed electron microscope and diffraction studies of the sub-oxides of vanadium have been reported by Cambini and co-workers, and an oxidation study, possibly complicated by carbon and/or nitrogen, has been published by Edington and Smallman. The results reported by these different authors are not in good agreement. For this study, high purity polycrystalline vanadium samples were electrochemically thinned in a dual jet polisher using a solution of 20% H2SO4, 80% CH3OH, and then oxidized in an ion-pumped ultra-high vacuum reactor system using spectroscopically pure oxygen. Samples were oxidized at 350°C and 100μ oxygen pressure for periods of 30,60,90 and 160 minutes. Since our primary interest is in the mechanism of the low pressure oxidation process, the oxidized samples were cooled rapidly and not homogenized. The specimens were then examined in the HVEM at voltages up to 500 kV, the higher voltages being necessary to examine thick sections for which the oxidation behavior was more characteristic of the bulk.

The High Resolution Scanning Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 316-317
Author(s):  
A. V. Crewe
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
High Vacuum ◽  
Scanning Transmission Electron Microscope ◽  
Ultra High Vacuum ◽  
Resolving Power ◽  
Imaging Characteristics ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Moment

The high resolution STEM is now a fact of life. I think that we have, in the last few years, demonstrated that this instrument is capable of the same resolving power as a CEM but is sufficiently different in its imaging characteristics to offer some real advantages.It seems possible to prove in a quite general way that only a field emission source can give adequate intensity for the highest resolution^ and at the moment this means operating at ultra high vacuum levels. Our experience, however, is that neither the source nor the vacuum are difficult to manage and indeed are simpler than many other systems and substantially trouble-free.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

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