Thermal Desorption Spectroscopy Study on the Hydrogen Behavior in a Plasma-Charged Aluminum

2016 ◽  
Vol 879 ◽  
pp. 1220-1225
Author(s):  
Toshiaki Manaka ◽  
Masaya Aoki ◽  
Goroh Itoh
Keyword(s):  
Thermal Desorption ◽  
Pure Aluminum ◽  
High Vacuum ◽  
Thermal Desorption Spectroscopy ◽  
Hydrogen Gas ◽  
Ultra High Vacuum ◽  
Trap States ◽  
Intergranular Cracking ◽  
High Hydrogen ◽  
Gas Plasma

Hydrogen in aluminum has been known to be the cause of blister and pore. Some aluminum alloy is susceptible to stress corrosion cracking, which is based on intergranular cracking arisen from hydrogen embrittlement. The behavior of hydrogen in aluminum has not been fully understood yet. Hydrogen gas plasma enables to introduce high hydrogen concentrations into specimen without Al (OH)3 layer on the surface of specimen. In this paper, we have investigated the behavior of hydrogen in a plasma charged aluminum by means of thermal desorption spectroscopy, a method to evaluate the amount and trap states of hydrogen. Cold-rolled pure aluminum were annealed, electro-polished and charged with hydrogen gas plasma. Immediately after hydrogen gas plasma charging, TDS tests were performed under ultra-high vacuum. The hydrogen desorption spectrums obtained by TDS tests had three peaks corresponding to the co-diffusion of hydrogen-vacancy pair, dislocation and pore. Compared to a sample without charging, in a plasma charged sample, the amount of hydrogen trapped in vacancies especially increased.

Tribochemistry of ZDOL Decomposition on Carbon Overcoats in Ultra-High Vacuum (UHV)

1999 ◽  
Vol 594 ◽  
Author(s):  
C. S. Bhatia ◽  
C.-Y. Chen ◽  
W. Fong ◽  
D. B. Bogy
Keyword(s):  
Thermal Desorption ◽  
Wear Track ◽  
High Vacuum ◽  
Catalytic Decomposition ◽  
Ultra High Vacuum ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Desorption Temperature ◽  
Two Distinct Temperatures ◽  
Carbon Overcoats

AbstractTribochemical studies of the effect of lubricant bonding on the tribology of the head/disk interface (HDI) were conducted using hydrogenated (CHx) carbon disk samples coated with perfluoropolyether ZDOL lubricant. The studies involved drag tests with uncoated and carboncoated Al2O3-TiC sliders and also thermal desorption experiments in an ultra-high vacuum (UHV) tribochamber. We observed that a larger mobile lubricant portion significantly enhances the wear durability of the (head/disk interface) HDI by providing a reservoir to constantly replenish the lubricant displaced in the wear track during drag tests. In the thermal desorption tests we observed two distinct temperatures of desorption. The mobile ZDOL layer is desorbed at the lower thermal desorption temperature and the residual bonded ZDOL layer is desorbed at the higher thermal desorption temperature. We also observed that the hydrogen evolution from CHx overcoats initiates lubricant catalytic decomposition with uncoated Al2O3/TiC sliders, forming CF3 (69) and C2F5 (119). The generation of Hydroflouric acid (HF) during thermal desorption experiments provides the formation mechanism of Lewis acid, which is the necessary component for catalytic reaction causing Z-DOL lube degradation.

Reconstructions upon thermal desorption in ultra high vacuum of InSe covered Si(111) surfaces

1998 ◽  
Vol 5 (4-6) ◽  
pp. 919-926 ◽  
Author(s):  
F. Proix ◽  
V. Panella ◽  
S. El Monkad ◽  
A. Glebov ◽  
J.P. Lacharme ◽  
...  
Keyword(s):  
Thermal Desorption ◽  
High Vacuum ◽  
Ultra High Vacuum

Relationship Between the Ductility and Impurity Hydrogen in Ni3Al

1994 ◽  
Vol 364 ◽  
Author(s):  
R. Chikaizumi ◽  
G. Itoh ◽  
M. Kanno ◽  
H. Okada
Keyword(s):  
High Vacuum ◽  
Tensile Tests ◽  
Hydrogen Gas ◽  
Ultra High Vacuum ◽  
Transgranular Fracture ◽  
Hydrogen Atoms ◽  
Impurity Hydrogen ◽  
The Moment ◽  
Evolution Behavior ◽  
Growth Of Voids

AbstractTensile tests were carried out on B-doped and undoped Ni3Al having different hydrogen contents in order to examine whether the amount of impurity hydrogen affects the ductility of Ni3Al. Specimens were melted either in a high vacuum of ∼10−3Pa or argon, isothermally forged and finally annealed for 15hr at 430°C in an ultra high vacuum of ∼10−3Pa or in argon, respectively. Measurement of hydrogen gas evolved from the specimen during the annealing at 430°C in an ultra high vacuum of ∼10−7Pa confirmed that vacuum treated specimen had actually smaller hydrogen content than the argon treated one. The ductility of vacuum treated specimens both B-doped and undoped was found to be larger than that of argon treated ones, which means a detrimental influence of hydrogen. Hydrogen evolution behavior during the test on B-dopcd specimens in an ultra high vacuum of ∼10−8Pa revealed that the amount of hydrogen gas evolved at the moment of fracture was smaller in vacuum treated specimens than in argon treated one. Impurity hydrogen atoms were considered to move and enhance the formation and growth of voids, accelerating transgranular fracture.

scholarly journals Methanol ice co-desorption as a mechanism to explain cold methanol in the gas-phase

2018 ◽  
Vol 612 ◽  
pp. A88 ◽  
Author(s):  
N. F. W. Ligterink ◽  
C. Walsh ◽  
R. G. Bhuin ◽  
S. Vissapragada ◽  
J. Terwisscha van Scheltinga ◽  
...  
Keyword(s):  
Gas Phase ◽  
Thermal Desorption ◽  
High Vacuum ◽  
Protoplanetary Disk ◽  
Ultra High Vacuum ◽  
Indirect Pathway ◽  
Cold Environments ◽  
Chemical Modelling ◽  
Phase Chemistry ◽  
The Impact

Context. Methanol is formed via surface reactions on icy dust grains. Methanol is also detected in the gas-phase at temperatures below its thermal desorption temperature and at levels higher than can be explained by pure gas-phase chemistry. The process that controls the transition from solid state to gas-phase methanol in cold environments is not understood. Aims. The goal of this work is to investigate whether thermal CO desorption provides an indirect pathway for methanol to co-desorb at low temperatures. Methods. Mixed CH3OH:CO/CH4 ices were heated under ultra-high vacuum conditions and ice contents are traced using RAIRS (reflection absorption IR spectroscopy), while desorbing species were detected mass spectrometrically. An updated gas-grain chemical network was used to test the impact of the results of these experiments. The physical model used is applicable for TW Hya, a protoplanetary disk in which cold gas-phase methanol has recently been detected. Results. Methanol release together with thermal CO desorption is found to be an ineffective process in the experiments, resulting in an upper limit of ≤ 7.3 × 10−7 CH3OH molecules per CO molecule over all ice mixtures considered. Chemical modelling based on the upper limits shows that co-desorption rates as low as 10−6 CH3OH molecules per CO molecule are high enough to release substantial amounts of methanol to the gas-phase at and around the location of the CO thermal desorption front in a protoplanetary disk. The impact of thermal co-desorption of CH3OH with CO as a grain-gas bridge mechanism is compared with that of UV induced photodesorption and chemisorption.

scholarly journals Triptycene-terminated thiolate and selenolate monolayers on Au(111)

2017 ◽  
Vol 8 ◽  
pp. 892-905 ◽  
Author(s):  
Jinxuan Liu ◽  
Martin Kind ◽  
Björn Schüpbach ◽  
Daniel Käfer ◽  
Stefanie Winkler ◽  
...  
Keyword(s):  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Thermal Desorption Spectroscopy ◽  
Ultra High Vacuum ◽  
Self Assembled Monolayers ◽  
X Ray ◽  
Infrared Reflection ◽  
Assembled Monolayers ◽  
X Ray Absorption

To study the implications of highly space-demanding organic moieties on the properties of self-assembled monolayers (SAMs), triptycyl thiolates and selenolates with and without methylene spacers on Au(111) surfaces were comprehensively studied using ultra-high vacuum infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy and thermal desorption spectroscopy. Due to packing effects, the molecules in all monolayers are substantially tilted. In the presence of a methylene spacer the tilt is slightly less pronounced. The selenolate monolayers exhibit smaller defect densities and therefore are more densely packed than their thiolate analogues. The Se–Au binding energy in the investigated SAMs was found to be higher than the S–Au binding energy.

Electrical characterisation of UHV-bonded silicon interfaces

2001 ◽  
Vol 681 ◽  
Author(s):  
A. Reznicek ◽  
S. Senz ◽  
O. Breitenstein ◽  
R. Scholz ◽  
U. Gösele
Keyword(s):  
Current Density ◽  
Wafer Bonding ◽  
Applied Voltage ◽  
High Current Density ◽  
Strong Dependence ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Bonding Energy ◽  
Constant Density ◽  
Trap States

ABSTRACTDirect wafer bonding can be used to mechanically and electrically connect semiconductors. In our experiments two 100 mm diameter (100) Si wafers (n-doping: 1014 cm−3) are first cleaned by standard chemical cleaning (RCA 1, 2). The surface is terminated by hydrogen after a HF dipping. The wafers are prebonded in air to protect the surface. After introduction into the ultra high vacuum (UHV) system the wafers are separated again. The hydrogen termination is released in a heating chamber. RHEED confirmed a surface reconstruction. The wafers are then cooled down to room temperature and bonded in UHV. The bonding energy is very close to the bulk bonding energy.Measurements of whole n-n wafers showed a linear relationship of voltage and current at a low current density of 0.05 A/cm2. The current flow is inhomogeneous, which is visible in IR- thermography images. Above 0.1 V the current density first saturates, but increases super- linearly for higher voltages. The electrical properties of a grain boundary can be modeled by a double Schottky barrier. The barrier height decreases with increasing applied voltage. C-V measurements show a strong dependence of capacitance on frequency, temperature and applied voltage.The capacitance increases with higher temperature and lower frequency. The interface state density can be estimated from the low temperature and high frequency capacitance limit as Dit = 1·1011 cm−2 eV−1 assuming a constant density of states.We can conclude that in order to avoid the undesirable effect of the potential barrier and trap states at the bonding interface a high doping near the interface is required for the application of wafer bonding to devices with a high current density across the bonded interface.

Low Temperature Silicon Epitaxy Grown by Electron-Beam Evaporation in an Ultra-High Vacuum System

1991 ◽  
Vol 237 ◽  
Author(s):  
Yung-Jen Lin ◽  
Tri-Rung Yew
Keyword(s):  
Electron Beam ◽  
Thermal Desorption ◽  
High Vacuum ◽  
High Energy ◽  
Electron Beam Evaporation ◽  
Ultra High Vacuum ◽  
Native Oxide ◽  
Vacuum System ◽  
Wafer Surface ◽  
Epitaxial Silicon

ABSTRACTThis paper presents the results of silicon epitaxial growth on silicon windows surrounded with oxide walls by electron-beam evaporation in an ultra-high vacuum system with a load-lock chamber. The wafer surface was in-situ cleaned in the growth chamber to remove native oxide by thermal desorption at about 840 °C and a base pressure of better than 2 × 10-9 Torr. The growth temperature was 200°C or higher. The pre-epitaxial silicon surface structure was inspected by reflection high energy electron diffraction (RHEED). The influence of the thermal desorption on the quality of the epi/substrate interface and epitaxial layers was studied. In addtion, the deposition parameters which control the epitaxial quality were investigated. The epitaxial films were characterized by cross-sectional trasmission electron microscopy (XTEM) and secondary ion mass spectroscopy (SIMS).

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