Preferential Sputtering of Tantalum Oxide: Reemission of Helium and Transient Effects in the Altered Layer

1986 ◽  
pp. 146-150
Author(s):  
B. Baretzky ◽  
E. Taglauer
Keyword(s):  
Tantalum Oxide ◽  
Transient Effects ◽  
Preferential Sputtering ◽  
Altered Layer

Preferential sputtering of coevaporated Cu-Ni film associated with altered layer

1978 ◽  
Vol 75 (2) ◽  
pp. L373-L375 ◽  
Author(s):  
K. Goto ◽  
T. Koshikawa ◽  
K. Ishikawa ◽  
R. Shimizu
Keyword(s):  
Preferential Sputtering ◽  
Altered Layer

SEGREGATION PHENOMENA ON PtxNi1−x LOW INDEX SINGLE CRYSTAL SURFACES STUDIED BY STM

1996 ◽  
Vol 03 (05n06) ◽  
pp. 1831-1845 ◽  
Author(s):  
P. VARGA ◽  
M. SCHMID ◽  
W. HOFER
Keyword(s):  
Single Crystal ◽  
Surface Segregation ◽  
Elevated Temperatures ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Crystal Surfaces ◽  
Single Crystal Surfaces ◽  
Chemical Ordering ◽  
Preferential Sputtering ◽  
Altered Layer

Surface segregation changes the composition of alloy surfaces. It influences both the geometrical and the chemical structure of the surface. In this paper segregation phenomena are shown for low index single crystal surfaces of different PtNi alloys which can be seen only by scanning tunneling microscopy (STM). STM experiments performed with atomic resolution revealed the existence of subsurface dislocation networks. A closer study of the conditions of their existence allowed us to understand the effects of preferential sputtering and annealing on the segregation behavior (i.e. building up a rather stable altered layer and its disappearance only at elevated temperatures). In addition, local chemical ordering in small domains and shifted row reconstructions with a large and varying periodicity (i.e. phenomena that are hardly seen by other methods like e.g. LEED) have been observed.

Collision dominated preferential sputtering of tantalum oxide

Vacuum ◽  
1992 ◽  
Vol 43 (12) ◽  
pp. 1207-1216 ◽  
Author(s):  
B Baretzky ◽  
W Möller ◽  
E Taglauer
Keyword(s):  
Tantalum Oxide ◽  
Preferential Sputtering

XPS-Analysis of Ion-Beam-Induced Oxidation (IBO) of AlxGa1−xAs Substrates

1992 ◽  
Vol 279 ◽  
Author(s):  
Josep-Lluis Alay ◽  
Wilfried Vandervorst
Keyword(s):  
Ion Beam ◽  
Heat Of Formation ◽  
Xps Analysis ◽  
Experimental Conditions ◽  
Oxidation Level ◽  
Preferential Sputtering ◽  
Altered Layer ◽  
The Matrix ◽  
Arsenic Oxidation ◽  
Lower Oxidation

ABSTRACTXPS analysis was used to characterise GaAs, Al0.4Ga0.6As and Al0.8Ga0.2As targets bombarded with an O2+ beam ranging from 1 keV to 5 keV. The bombardments were carried out at different angles of incidence from 0° to 60°. In all cases a strong preferential sputtering of arsenic gives rise to an As-depleted altered layer, formed by a mixture of gallium, arsenic and aluminium oxides with metallic gallium and arsenic. Aluminium and gallium are preferentially oxidized, a fact that correlates with the corresponding heat of formation of the oxides, whereas the arsenic oxidation requires a minimum incorporation of oxygen into the matrix. For all experimental conditions a considerably lower oxidation level has been observed in every case as compared to the IBO of silicon.

DYNAMIC PROCESSES OF ALTERED LAYER FORMATION IN Cu-Pt ALLOYS UNDER ION BOMBARDMENT

1996 ◽  
Vol 03 (05n06) ◽  
pp. 1811-1821 ◽  
Author(s):  
CHUNFEI LI ◽  
TATSUYA ASAHATA ◽  
RYUICHI SHIMIZU
Keyword(s):  
Steady State ◽  
Ion Bombardment ◽  
Cooling Effect ◽  
Layer Formation ◽  
Transient Stage ◽  
Enhanced Diffusion ◽  
Preferential Sputtering ◽  
Radiation Enhanced Diffusion ◽  
Initial Stage ◽  
Altered Layer

Three different experimental approaches have been developed to study the dynamic process of subsurface altered layer formation in a Cu-Pt alloy under Ar + ion bombardment: (1) sputter neutral mass spectrometry by multiphoton ionization (MPI-SNMS) for the study of preferential sputtering caused by the collision cascade process in the very initial stage of sputtering; (2) ion scattering spectroscopy (ISS)-Auger electron spectroscopy (AES) sequential measurements for investigating radiation-enhanced Gibbsian segregation in the transient stage of sputtering; (3) an approach based on ISS monitoring by prompt switching of the ion bombardment with ( He ++ Ar +) ions to that with He + ions, for revealing the cooling effect in radiation-enhanced diffusion in the final steady state of sputtering. For this we have developed a specific coevaporating device for depositing Cu and Pt simultaneously on a substrate at constant deposition rate. The coevaporating device was attached to both of the specimen chambers of the Auger microprobe, JAMP-3, and of the MPI-SNMS apparatus. The results have clearly revealed: (i) ion bombardment causes a preferential sputtering of Cu atoms in the very initial stage of sputtering, (ii) followed by gradual formation of an altered layer as ion sputtering proceeds in the transient stage, and (iii) finally the alloy system approaches a steady state where the composition profile is controlled by cascade mixing, radiation-enhanced Gibbsian segregation and radiation-enhanced diffusion to satisfy the mass balance law. In the steady state the approach (3) has, first, revealed that the cooling effect does exist in radiation-enhanced diffusion.

Preferential Sputtering of Ni3Al Single Crystals Studied Using Atom-Probe Field-Ion Microscopy and XPS

1981 ◽  
Vol 39 ◽  
pp. 16-17
Author(s):  
M.P. Thomas ◽  
A.R. Waugh ◽  
M.J. Southon ◽  
Brian Ralph
Keyword(s):  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Depth Profiling ◽  
Analytical Techniques ◽  
Atom Probe ◽  
Probe Field ◽  
Preferential Sputtering ◽  
Argon Ion Bombardment ◽  
Argon Ion

It is well known that ion-induced sputtering from numerous multicomponent targets results in marked changes in surface composition (1). Preferential removal of one component results in surface enrichment in the less easily removed species. In this investigation, a time-of-flight atom-probe field-ion microscope A.P. together with X-ray photoelectron spectroscopy XPS have been used to monitor alterations in surface composition of Ni3Al single crystals under argon ion bombardment. The A.P. has been chosen for this investigation because of its ability using field evaporation to depth profile through a sputtered surface without the need for further ion sputtering. Incident ion energy and ion dose have been selected to reflect conditions widely used in surface analytical techniques for cleaning and depth-profiling of samples, typically 3keV and 1018 - 1020 ion m-2.

Corrections for surface films in microanalysis by EDS and EELS

1992 ◽  
Vol 50 (2) ◽  
pp. 1230-1231
Author(s):  
J. Bentley ◽  
E. A. Kenik
Keyword(s):  
Hydrocarbon Contamination ◽  
Specimen Preparation ◽  
Surface Films ◽  
Ion Milling ◽  
Preferential Sputtering ◽  
Electron Energy Loss Spectrometry ◽  
Composition Determination ◽  
Analytical Electron ◽  
First Order Correction ◽  
Electron Energy Loss

Common artifacts on analytical electron microscope (AEM) specimens prepared from bulk materials are surface films with altered structure and composition that result from electropolishing, oxidation, hydrocarbon contamination, or ion milling (preferential sputtering or deposition of sputtered specimen or support material). Of course, the best solution for surface films is to avoid them by improved specimen preparation and handling procedures or to remove them by low energy ion sputter cleaning, a capability that already exists on some specialized AEMs and one that is likely to become increasingly common. However, the problem remains and it is surprising that surface films have not received more attention with respect to composition determination by energy dispersive X-ray spectrometry (EDS) and electron energy loss spectrometry (EELS).For EDS, an effective first-order correction to remove the contribution of surface films on wedge shaped specimens is to subtract from the spectrum of interest a spectrum obtained under identical conditions (probe current, diffracting conditions, acquisition live time) from a thinner region of the specimen.

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