X-ray analysis of tantalum films triode-sputtered in argon-oxygen mixtures

1973 ◽  
Vol 15 (1) ◽  
pp. 15-30 ◽  
Author(s):  
W.D. Westwood
Keyword(s):  
X Ray ◽  
Tantalum Films

Stress and Phase Changes in Ion-Assisted Evaporation of Thin Tantalum Films

1991 ◽  
Vol 235 ◽  
Author(s):  
R. A. Roy ◽  
Philip Catania
Keyword(s):  
Alpha Phase ◽  
Ion Flux ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Tantalum Films ◽  
Ion Energies ◽  
Argon Ion ◽  
Flux Incident

ABSTRACTIon-assisted evaporation was used to study the stress and phase changes in thin Ta films. Using a series of ion energies from 63 to 500 eV, the stress in 100 nm thick films was changed from tensile to compressive by increasing the argon ion flux incident on the growing films. The resulting films were characterized primarily by x-ray diffraction and electrical resistivity measurements, as well as RBS. The resistivity in all sets of films shows a large decrease with increasing argon ion flux. The x-ray diffraction results are somewhat more complex, but suggest that increasing ion flux does change the amount of alpha phase present.

scholarly journals X-ray characterization of oriented β-tantalum films

2004 ◽  
Vol 469-470 ◽  
pp. 404-409 ◽  
Author(s):  
Sandeep Kohli ◽  
Patrick R. McCurdy ◽  
Christopher D. Rithner ◽  
Peter K. Dorhout ◽  
Ann M. Dummer ◽  
...  
Keyword(s):  
X Ray ◽  
Tantalum Films

scholarly journals Tantalum diffusion barrier grown by inorganic plasma-promoted chemical vapor deposition: Performance in copper metallization

2000 ◽  
Vol 15 (12) ◽  
pp. 2800-2810 ◽  
Author(s):  
Alain E. Kaloyeros ◽  
Xiomeng Chen ◽  
Sarah Lane ◽  
Harry L. Frisch ◽  
Barry Arkles
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Rutherford Backscattering Spectrometry ◽  
Chemical Vapor ◽  
Diffusion Barriers ◽  
Copper Metallization ◽  
X Ray ◽  
Force Microscopy ◽  
Tantalum Films

As-deposited and annealed tantalum films, grown by plasma-promoted chemical vapor deposition (PPCVD) using pentabromotantalum and hydrogen as coreactants, were evaluated as diffusion barriers in copper metallization. Stacks consisting of 500-nm-thick sputtered Cu/55-nm-thick untreated PPCVD Ta/Si were annealed in argon in the range 450 to 650 °C, in 50 °C intervals, along with sputtered Cu/preannealed PPCVD Ta/Si and sputtered Cu/sputtered Ta/Si stacks of identical thickness. Pre- and postannealed stacks were characterized by x-ray photoelectron spectroscopy, Auger electron spectroscopy, Rutherford backscattering spectrometry, hydrogen profiling, x-ray diffraction, atomic force microscopy, sheet resistance measurements, and Secco chemical treatment and etch-pit observation by scanning electron microscopy. The sputtered and preannealed PPCVD Ta films acted as viable diffusion barriers up to 550 °C, while the as-deposited PPCVD Ta films failed above 500 °C. In all cases, breakdown occurred through the migration of Cu into Si, rather than an interfacial reaction between Ta and Si, in agreement with previously reported results for sputtered Ta films. The accelerated barrier failure for as-deposited PPCVD Ta might have been caused by the presence of approximately 20 at.% hydrogen in the as-deposited PPCVD Ta, an observation which was supported by the enhanced performance of the same PPCVD Ta films after annealing-induced hydrogen removal.

Cracking and Delamination of Vapour-Deposited Tantalum Films

1990 ◽  
Vol 188 ◽  
Author(s):  
R. M. Fisher ◽  
J. Z. Duan ◽  
J. B. Liu
Keyword(s):  
Electron Diffraction ◽  
Glass Substrate ◽  
Vapour Deposition ◽  
Critical Thickness ◽  
Stress Gradient ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tantalum Films ◽  
Glass Interface ◽  
Good Agreement

ABSTRACTTantalum films begin to crack and spall during vapour deposition on glass at a thickness of 180 nm. Islands and ribbons, 10 – 30 µm in size, delaminate by crack growth along the Ta/glass interface for several gIm after which the crack penetrates into the glass to a depth of 0.5–1 µm and complete spalling occurs. X-ray diffraction showed that about 50 % of the original bct, β-tantalum, phase had transformed to the bcc α-Ta phase. When Ta was deposited on glass that was first covered with 52 nm of copper, spalling was observed to begin at a thickness of 105 nm. In this case, the film first cracks and then peels along the Cu/glass interface and curls into scrolls indicating the presence of a small stress gradient. X-ray diffraction of the asdeposited film, and electron diffraction of ion-milled flakes, showed that Ta films deposited on Cu-coated glass almost completely transform to bcc α-Ta. The critical thickness for delamination along the Cu/glass interface is about 1/2 that for cracking in the glass substrate when an intermediate layer of Cu is not present. All of the above findings are in good agreement with previous observations on Cr films.

Compressive Stress Increase With Repeated Thermal Cycling in Tantalum(Oxygen) Thin Films

1993 ◽  
Vol 308 ◽  
Author(s):  
C. Cabral ◽  
L.A. Clevenger ◽  
R.G. Schad
Keyword(s):  
Thin Films ◽  
Thermal Cycling ◽  
Compressive Stress ◽  
Resistivity Measurement ◽  
Depth Profiling ◽  
Poor Quality ◽  
X Ray ◽  
Tantalum Films ◽  
Auger Electron Spectroscopy Depth ◽  
Sputter Deposited

ABSTRACTStresses which build up in thin films, such as tantalum, during thermal processing, can cause major reliability problems in x-ray optics and electronic applications. We have demonstrated that 50 nm to 200 nm thick sputtered beta tantalum thin films undergo repeated compressive stress increases when thermally cycled from room temperature to 400°C (at 10°C/min) and back in a purified He ambient because of low levels of oxygen gettered by the tantalum. The oxygen contamination is a result of the poor quality of the quartz annealing chamber atmospheric seal. As-deposited stress in the sputter deposited tantalum films ranges from -1 to -4 GPa. The compressive stress build up was monitored in situ and was shown to increase -0.5 GPa on average after each thermal cycle for a final value of -6 to -7 GPa after seven cycles. After being cycled thermally seven times any perturbation of the film such as a four point probe resistivity measurement can cause the film to instantaneously crack in a serpentine pattern relieving the large compressive stress. Auger electron spectroscopy depth profiling analysis indicated that the as-deposited films contained one atomic percent oxygen which increased to eight to twelve percent after seven thermal cycles accompanied by an approximate doubling in resistivity. In conclusion, the increase in oxygen concentration in tantalum thin films which occurs upon thermal cycling leads to a repetitive increase in compressive stress which could be detrimental when the films are used in x-ray or electronic applications.

Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

1994 ◽  
Vol 144 ◽  
pp. 275-277
Author(s):  
M. Karlický ◽  
J. C. Hénoux
Keyword(s):  
Time Distribution ◽  
Electron Bombardment ◽  
Spatial Evolution ◽  
Superthermal Electrons ◽  
Flare Loop ◽  
X Ray ◽  
Superthermal Electron ◽  
Flare Loops ◽  
Chromospheric Evaporation ◽  
Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

Some Problems in Understanding the Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 1-9
Author(s):  
A. H. Gabriel
Keyword(s):  
Solar Corona ◽  
Solar Atmosphere ◽  
Theoretical Modelling ◽  
Total System ◽  
Major Advance ◽  
X Ray ◽  
Proper Perspective ◽  
Space Observations

The development of the physics of the solar atmosphere during the last 50 years has been greatly influenced by the increasing capability of observations made from space. Access to images and spectra of the hotter plasma in the UV, XUV and X-ray regions provided a major advance over the few coronal forbidden lines seen in the visible and enabled the cooler chromospheric and photospheric plasma to be seen in its proper perspective, as part of a total system. In this way space observations have stimulated new and important advances, not only in space but also in ground-based observations and theoretical modelling, so that today we find a well-balanced harmony between the three techniques.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

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