Study of Oxygen Diffusion in Polycrystalline ZnO by SIMS

2009 ◽  
Vol 289-292 ◽  
pp. 523-530
Author(s):  
Antônio Claret Soares Sabioni ◽  
Antônio Márcio J.M. Daniel ◽  
Anne Marie Huntz ◽  
Wilmar Barbosa Ferraz ◽  
François Jomard
Keyword(s):  
Grain Boundary ◽  
Oxygen Pressure ◽  
Diffusion Coefficients ◽  
Effective Charge ◽  
Oxygen Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Mechanism ◽  
Bulk Diffusion ◽  
Interstitial Oxygen ◽  
Exchange Method

Oxygen diffusion coefficients were measured in polycrystalline ZnO by means of the gas-solid exchange method using the isotope 18O as the oxygen tracer. The diffusion annealings were performed at 892oC and 992oC, in an Ar+18O2 atmosphere under oxygen partial pressures from 0.1 to 1atm. After the diffusion annealings, the 18O diffusion profiles were established by secondary ion mass spectrometry (SIMS). Increasing the oxygen pressure leads to an increase of the oxygen diffusion in ZnO. The bulk diffusion coefficients depends on oxygen pressure according to , at 882oC, or , at 992oC, which indicates that the oxygen bulk diffusion mechanism should preferentially take place by means of interstitial oxygen having a null effective charge. The grain boundary diffusion coefficients show little dependence on oxygen pressure at 882oC, given by , which should correspond to a diffusion mechanism by means of interstitial oxygen, with a double negative charge, but at 992oC this dependence is corresponding to a diffusion mechanism by interstitial oxygen having a null effective charge. The results also show that the grain boundary is a fast path for the oxygen diffusion in polycrystalline ZnO.

First Study of Oxygen Diffusion in a ZnO - Based Commercial Varistor

2009 ◽  
Vol 289-292 ◽  
pp. 339-345
Author(s):  
Antônio Claret Soares Sabioni ◽  
Antônio Márcio J.M. Daniel ◽  
Renaud Metz ◽  
Anne Marie Huntz ◽  
François Jomard
Keyword(s):  
Grain Boundaries ◽  
Oxygen Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Bulk Diffusion ◽  
Simple Explanation ◽  
Exchange Method ◽  
Microstructural Parameters ◽  
Secondary Ion ◽  
Oxygen Tracer ◽  
Diffusion Profiles

Oxygen diffusion coefficients were determined in a commercial ZnO-based varistor by means of the gas-solid exchange method using the isotope 18O as the oxygen tracer. The diffusion annealings were performed at 892, 942, 992 and 1092oC, in an Ar + 18O2 atmosphere under an oxygen partial pressure of 0.2 atm. After the diffusion annealings, the 18O diffusion profiles were established by secondary ion mass spectrometry (SIMS). The results show an increase of the oxygen diffusion in the varistor, both in bulk and in grain boundaries, when compared to the oxygen diffusion in undoped ZnO. The increase of the oxygen bulk diffusion in the varistor agrees with an interstitial mechanism for the oxygen diffusion. The results also show that the grain boundary is a fast path for the oxygen diffusion in the varistor. However, the oxygen diffusion in the grain boundaries of the varistor seems to depend on several chemical and microstructural parameters and does not allow a simple explanation.

Surface Oxygen Exchange Kinetics and Oxygen Diffusion Rates in Ysz Single Crystals

1998 ◽  
Vol 548 ◽  
Author(s):  
N.I. Joos ◽  
P.A.W. van der Heide ◽  
J.R. Liu ◽  
R. Christoffersen ◽  
W.K. Chu ◽  
...  
Keyword(s):  
Activation Energy ◽  
Exchange Rates ◽  
Diffusion Coefficients ◽  
Oxygen Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Depth Profiling ◽  
Bulk Diffusion ◽  
Nuclear Reaction Analysis ◽  
Surface Exchange ◽  
Bulk Oxygen

ABSTRACTIsotope exchange with C18O2 followed by depth profiling analysis was used to study surface exchange and bulk diffusion of oxygen in single crystal ((100) surface orientation) yttria-stabilized zirconia (YSZ) in the temperature range 250°C - 350°C. The depth profiles, which were obtained using 18O(ρ,α)15N nuclear reaction analysis (NRA) and secondary ion mass spectrometry (SIMS), reveal both the bulk oxygen diffusion coefficients (D) and surface exchange coefficients (k). Bulk oxygen diffusion coefficients are consistent with an extrapolation to lower temperature of previously published results with an activation energy of 114 kJ/mol (1.2 eV). The surface exchange rates, however, depend strongly on the gas exchange species. Much higher exchange rates are observed with C18O2 than with 18O2 (over four orders of magnitude when compared to an extrapolation to lower temperatures of previously published results) with a measured activation energy of 152 kJ/mol (1.6 eV). This faster surface exchange rate enabled measurable 18O tracer profiles to be generated at lower temperatures than previously reported, further contributing to the understanding of YSZ material properties and bringing to light a possible order/disorder transition similar to that previously observed at 650°C.

Stress Generation during Grain Boundary Interdiffusion

2011 ◽  
Vol 309-310 ◽  
pp. 19-28 ◽  
Author(s):  
Leonid Klinger ◽  
Eugen Rabkin
Keyword(s):  
Stress Field ◽  
Grain Boundary ◽  
Diffusion Coefficients ◽  
Concentration Distribution ◽  
Boundary Diffusion ◽  
Elastic Stress ◽  
Bulk Diffusion ◽  
Stress Generation ◽  
Additional Material ◽  
Coupled Diffusion

A grain boundary interdiffusion in a semi-infinite bicrystal under the conditions of negligible bulk diffusion is considered. We show that the inequality of intrinsic grain boundary diffusion coefficients of the two components leads to plating out of additional material at the grain boundary in the form of extra material wedge, which generates an elastic stress field in the vicinity of the grain boundary. We solved a coupled diffusion/elasticity problem and determined the time-dependent stress field and concentration distribution in the vicinity of the grain boundary.

Diffusion and solubility of holmium ions in barium titanate ceramics

2004 ◽  
Vol 19 (12) ◽  
pp. 3512-3520 ◽  
Author(s):  
Junichi Itoh ◽  
Hajime Haneda ◽  
Shunichi Hishita ◽  
Isao Sakaguchi ◽  
Naoki Ohashi ◽  
...  
Keyword(s):  
Barium Titanate ◽  
Grain Boundary ◽  
Diffusion Coefficients ◽  
Boundary Diffusion ◽  
Diffusion Mechanism ◽  
Annealed Sample ◽  
Lattice Diffusion ◽  
Grain Boundary Diffusion ◽  
A Site ◽  
Titanate Ceramics

Ho ion solubility and diffusivity were evaluated in barium titanate ceramics in which Ho ions were implanted with an accelerating voltage of 500 keV. The depth profile of the ions was composed of three regions in the post-annealed sample: the first was the precipitation region, the second was a region created by lattice diffusion of Ho ions, and the third was a region created by grain-boundary diffusion. The Ho lattice diffusion characteristics were similar to those of Ni ion diffusion in barium titanate ceramics, and we concluded that the diffusion mechanism was the same as that responsible for Ni ions. The Ho ions diffused through the B-site (Ti-site) and were then exchanged with A-site ions. This mechanism suggests that a small number of Ho ions dissolved in the B-site. Preferential grain-boundary diffusion was also observed. The grain-boundary diffusion coefficients were four to five orders of magnitude larger than the volume diffusion coefficients. The solubility of Ho ions was estimated to be a few thousand parts per million in barium titanate ceramics.

Grain Boundary Diffusion in Cation-Doped Superplastic 3Y-TZP

2006 ◽  
Vol 45 ◽  
pp. 1626-1631
Author(s):  
Marek Boniecki ◽  
Rafał Jakieła ◽  
Zdzislaw Librant ◽  
Wladyslaw Wesolowski ◽  
Danuta Dabrowska ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Thin Films ◽  
Grain Boundary ◽  
Diffusion Coefficients ◽  
Boundary Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Tetragonal Zirconia ◽  
Grain Boundary Diffusion ◽  
Depth Profiles ◽  
Secondary Ion

The superplastic flow in tetragonal zirconia polycrystals stabilised 3mol% Y2O3 (3YTZP) is strongly affected by the dopant cations, which segregate at the grain boundary. It is proposed that this flow is controlled by grain boundary diffusion of Zr4+ ions and therefore the dopant cations should change the grain boundary diffusion. In order to prove this thesis the measurements of grain boundary diffusion coefficients were made using Hf4+ ions as tracer. Zirconia samples were doped with 1mol% of Al2O3, SiO2, MgO, MgAl2O4, GeO2 and TiO2. The tracer was deposited on the surface of the zirconia specimens by placing several drops of hafnium nitrate and then drying at 373 K. In this way, thin films of HfO 2 were obtained. The samples were heated in the range 1553 – 1773 K for 1 to 24 h. The concentration versus depth profiles were measured using secondary ion mass spectrometry (SIMS). Calculated hence grain boundary diffusion coefficients were several times bigger for doped samples than for pure 3Y-TZP samples.

Study of Fe Diffusion in Cr2O3 by Secondary Ion Mass Spectrometry

2005 ◽  
Vol 237-240 ◽  
pp. 940-945
Author(s):  
Antônio Claret Soares Sabioni ◽  
Anne Marie Huntz ◽  
F. Silva ◽  
François Jomard
Keyword(s):  
Mass Spectrometry ◽  
Activation Energy ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Bulk Diffusion ◽  
Grain Boundary Diffusion ◽  
Iron Diffusion ◽  
Ion Mass Spectrometry ◽  
Secondary Ion

Chromia protective layers are used to prevent corrosion by oxidation of many alloys, such as the stainless steels, for instance. To check if chromia is a barrier to the outward diffusion of iron in these alloys, iron diffusion in chromia was studied in both polycrystals and oxide films formed by oxidation of Ni-30Cr alloy in the temperature range 700-1100°C at an oxygen pressure equal to 10-4 atm. An iron film of about 70 nm thick was deposited on the chromia surface, and after the diffusing treatment, the iron depth profiles were established by secondary ion mass spectrometry (SIMS). Using a solution of the Fick’s second law for diffusion from a thick film, effective or bulk diffusion coefficients were determined in a first penetration domain. Then, Le Claire’s and Hart’s models allowed both the bulk diffusion coefficient and the grain boundary diffusion parameter (aDgbd) to be obtained in a second penetration domain. Iron bulk and grain boundary diffusion does not vary significantly according to the nature-microstructure of chromia. The activation energy of grain boundary diffusion is at least equal or even greater than the activation energy of bulk diffusion, probably on account of segregation phenomena. Iron diffusion was compared to cationic self-diffusion and related to the protective character of chromia.

Measurement of the Impurity Diffusivity of Cu in Fe by Laser Induced Breakdown Spectrometry

2005 ◽  
Vol 237-240 ◽  
pp. 266-270 ◽  
Author(s):  
Chan Gyu Lee ◽  
Jung Han Lee ◽  
Byeong Seon Lee ◽  
Yong Ill Lee ◽  
Toshitada Shimozaki ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Diffusion Coefficients ◽  
Boundary Diffusion ◽  
Volume Diffusion ◽  
Diffusion Mechanism ◽  
Grain Boundary Diffusion ◽  
Impurity Diffusion ◽  
Boundary Diffusion Coefficient ◽  
Laser Induced Breakdown ◽  
Good Agreement

The impurity diffusion coefficients of Cu in Fe have been determined in the temperature range of 1073 - 1163 K by means of Laser Induced Breakdown Spectrometry (LIBS). The volume diffusion coefficients for Cu impurity diffusion in a-iron found in this work are in good agreement with the previously published result. The grain boundary diffusion coefficient gb D s d was also calculated using the volume diffusivity and processing the tails of the measured profiles. The values of the activation energy for volume and grain boundary diffusion were approximately 280 and 161 kJmol-1, respectively. This indicates the possibility of a monovacancy diffusion mechanism in case of volume diffusion. The results for the diffusion coefficients are Dv= 2.2 ×10-2exp(-280 kJmol-1/RT) m2s-1 and gb D s d = 2.6 ×10-11exp(-161 kJmol-1/RT) m3s-1.

Al Diffusion in Polycrystalline Cu

2008 ◽  
Vol 1079 ◽  
Author(s):  
Florian Gstrein ◽  
Harold Kennel ◽  
Andre Budrevich ◽  
Barbara Miner ◽  
John Plombon ◽  
...  
Keyword(s):  
Thin Films ◽  
Diffusion Coefficients ◽  
Room Temperature ◽  
Diffusion Mechanism ◽  
Bulk Diffusion ◽  
Polycrystalline Copper ◽  
Segregation Behavior ◽  
Etch Stop ◽  
Secondary Ion ◽  
Diffusion Profiles

ABSTRACTThe diffusion of aluminum (Al) from a source sandwiched between polycrystalline copper (Cu) thin films was investigated as a function of time and temperature through secondary ion mass spectroscopy (SIMS) and continuum simulations. Extracted diffusion coefficients for the bulk were in line with literature values. In order to simulate the experimentally derived diffusion profiles at temperatures where bulk diffusion is not the dominant diffusion mechanism (room temperature to 350 °C), it was necessary to explicitly include the re-distribution of Al as a result of Cu grain growth during anneal. Aluminum has the tendency to segregate to the Cu/liner and Cu/etch stop (ES) interface. The tendency of Al to segregate to the liner is ten times stronger for ruthenium (Ru) than for tantalum (Ta). In 100 nm wide dual damascene structures lined with Ru, this segregation behavior was responsible for the Al depletion in bulk Cu and for the Al depletion at the Cu/ES interface.

Diffusivity and Diffusion Mechanism of Oxygen in Silicon

1985 ◽  
Vol 59 ◽  
Author(s):  
S.-Tong Lee ◽  
D. Nichols
Keyword(s):  
Mass Spectrometry ◽  
Point Defect ◽  
Point Defects ◽  
Oxygen Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Mechanism ◽  
Processing Conditions ◽  
Float Zone ◽  
And Diffusion ◽  
Secondary Ion

ABSTRACTThe diffusivities of oxygen in Czochralski Si (CZ-Si) and float-zone Si (FZ-Si) have been measured by using secondary ion mass spectrometry. The diffusivity at 700–1160°C deduced from the outdiffused profiles of oxygen incorporated in CZ-Si shows little or no dependence on processing conditions and can be expressed as D = 0.14 exp(−2.53 eV/kT) cm2/s. Diffusivity at 700–1100°C of oxygen implanted in FZ-Si is insensitive to doses and follows D = 0.13 exp(−2.50 eV/kT) cm2/s, which agrees remarkably well with CZ-Si data. Since large variations in point-defect concentrations existed under the conditions studied, the excellent agreement among the diffusivities leads to the conclusion that point defects in Si have little effect on oxygen diffusion. This demonstrates that oxygen diffuses primarily via an interstitial mechanism in the temperature range studied.

Diffusion Processes in Silicides: A Comparison Between Bulk and Thin Film Phase Formation.

1995 ◽  
Vol 402 ◽  
Author(s):  
Patrick Gas ◽  
Francois D'Heurle
Keyword(s):  
Thin Films ◽  
Diffusion Coefficients ◽  
Diffusion Processes ◽  
Diffusion Mechanism ◽  
Bulk Diffusion ◽  
Tracer Diffusion ◽  
Reactive Diffusion ◽  
Unique Source ◽  
Indirect Analysis ◽  
Dopant Redistribution

AbstractDiffusion processes in silicide thin films play a key role both during their formation by reactive diffusion or during their use. However our unique source of information was provided by indirect analysis: growth of thin films and dopant redistribution which are quite difficult to analyse in terms of diffusion mechanisms. Recent tracer experiments conducted in bulk silicides are presented. They allow a determination of both volume (v) and grain boundary (gb) diffusion coefficients. Contrary to what is observed in certain intermetallic compounds no fast volume diffusion mechanism was found. The main difference with the behaviour of pure metals is a slightly higher value of the ratio Qgb/Qv which makes gb diffusion an efficient process in a wider temperature range.A quantitative analysis of diffusion processes during silicide formation is then possible. As an example we propose a comparison between the kinetics of growth of thin films and bulk diffusion couples in the Co/Si and Ti/Si systems. Providing that attention is paid to: i) the laws of growth which are slightly different for a phase growing simultaneously with others (bulk) and one phase growing alone (thin films), and ii) the grain size of the growing phase which is strongly dependant on temperature and thicknesses excellent agreement is obtained between the two sets of measurements. Moreover the growth rates may be calculated quite accurately from the values of the volume and gb tracer diffusion coefficients. This stresses and quantifies the role of interfacial diffusion in thin films behaviour.

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