Kinetic Investigations of the Initial Oxidation Stage of Copper by In-Situ UHV-TEM

1996 ◽  
Vol 466 ◽  
Author(s):  
J. C. Yang ◽  
M. Yeadon ◽  
B. Kolasa ◽  
D. Olynick ◽  
J. M. Gibson
Keyword(s):  
Copper Film ◽  
Quantitative Model ◽  
Nucleation And Growth ◽  
Initial Oxidation ◽  
Methanol Vapor ◽  
In Situ Oxidation ◽  
Transmission Electron ◽  
Oxidation Stage ◽  
Kinetic Investigations

ABSTRACTWe have examined the nucleation and growth of copper oxides formed by in-situ oxidation of copper thin films inside a modified transmission electron microscope (TEM). Based on this data, we have developed a semi-quantitative model of the initial oxidation stage where the dominant mechanism for transport, nucleation and growth of oxide islands is oxygen diffusion on the surface. The copper oxide can be desorbed by annealing and introducing methanol vapor into the chamber. The clean copper film can be oxidized by introducing oxygen gas. Both the desorption and oxidation processes were observed by planar TEM techniques. The copper film was oxidized in-situ at a partial pressure of 5×104 torr. Cu2O islands, which formed epitaxially to the copper film, nucleated and grew into the copper film.

In-Situ UHV Tem Investigations of the Initial Oxidation Stage of Copper Thin Films

1997 ◽  
Vol 481 ◽  
Author(s):  
J. C. Yang ◽  
M. Yeadon ◽  
B. Kolasa ◽  
J. M. Gibson
Keyword(s):  
Oxygen Diffusion ◽  
Copper Film ◽  
Nucleation And Growth ◽  
Rate Theory ◽  
Initial Oxidation ◽  
Nucleation Sites ◽  
Partial Pressures ◽  
Oxidation Stage ◽  
Preferential Nucleation

ABSTRACTThe nucleation and growth of Cu2O due to oxidation of Cu(001) films were monitored at various temperatures and oxygen partial pressures. For all examined temperatures and pressures, Cu2O islands were observed to form epitaxially with respect to the copper film. The nucleation of these oxide islands was homogeneous –no clear evidence was observed for either steps or dislocations being preferential nucleation sites. Based on this data, we have developed a semiquantitative model of the initial oxidation stage where the dominant mechanism for transport, nucleation and growth of oxide islands is oxygen diffusion on the Cu surface. We are presently comparing our experimental data with nucleation rate theory, where the predictions qualitatively describe our observations, but not quantitatively.

scholarly journals Surface Kinetics of Copper Oxidation Investigated by In Situ Ultra-high Vacuum Transmission Electron Microscopy

2001 ◽  
Vol 7 (6) ◽  
pp. 486-493 ◽  
Author(s):  
Judith C. Yang ◽  
Mridula D. Bharadwaj ◽  
Guangwen Zhou ◽  
Lori Tropia
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Water Vapor ◽  
High Vacuum ◽  
Quantitative Model ◽  
Ultra High Vacuum ◽  
Copper Oxidation ◽  
Initial Oxidation ◽  
Transmission Electron

AbstractWe review our studies of the initial oxidation stages of Cu(001) thin films as investigated by in situ ultra-high vacuum transmission electron microscopy. We present our observations of surface reconstruction and the nucleation to coalescence of copper oxide during in situ oxidation in O2. We have proposed a semi-quantitative model, where oxygen surface diffusion is the dominant mechanism of the initial oxidation stages of Cu. We have also investigated the effect of water vapor on copper oxidation. We have observed that the presence of water vapor in the oxidizing atmosphere retards the rate of Cu oxidation and Cu2O is reduced when exposed directly to steam.

Initial Oxidation Kinetics of Cu(100), (110), and (111) Thin Films Investigated by in Situ Ultra-high-vacuum Transmission Electron Microscopy

2005 ◽  
Vol 20 (7) ◽  
pp. 1684-1694 ◽  
Author(s):  
Guangwen Zhou ◽  
Judith C. Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Diffusion ◽  
High Vacuum ◽  
Nucleation And Growth ◽  
Ultra High Vacuum ◽  
Initial Oxidation ◽  
Transmission Electron ◽  
Oxygen Surface

The initial oxidation stages of Cu(100), (110), and (111) surfaces have been investigated by using in situ ultra-high-vacuum transmission electron microscopy (TEM) techniques to visualize the nucleation and growth of oxide islands. The kinetic data on the nucleation and growth of oxide islands shows a highly enhanced initial oxidation rate on the Cu(110) surface as compared with Cu(100), and it is found that the dominant mechanism for the nucleation and growth is oxygen surface diffusion in the oxidation of Cu(100) and (110). The oxidation of Cu(111) shows a dramatically different behavior from that of the other two orientations, and the in situ TEM observation reveals that the initial stages of Cu(111) oxidation are dominated by the nucleation of oxide islands at temperatures lower than 550 °C, and are dominated by two-dimensional oxide growth at temperatures higher than 550 °C. This dependence of the oxidation behavior on the crystal orientation and temperature is attributed to the structures of the oxygen-chemisorbed layer, oxygen surface diffusion, surface energy, and the interfacial strain energy.

The Low-temperature Initial Oxidation Stages of Cu(100) Investigated by in situ Ultra-high-vacuum Transmission Electron Microscopy

2005 ◽  
Vol 20 (7) ◽  
pp. 1910-1917 ◽  
Author(s):  
L. Sun ◽  
J.C. Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Vacuum ◽  
Three Dimensional ◽  
Nucleation And Growth ◽  
Ultra High Vacuum ◽  
Initial Oxidation ◽  
Triangular Shape ◽  
Transmission Electron

The nucleation and growth of Cu2O islands due to Cu(100) oxidation at temperatures from 200 to 350 °C have been observed by in situ ultra-high-vacuum transmission electron microscopy. For this temperature range, epitaxial Cu2O islands form a triangular shape with rounded edges when Cu(100) is exposed to dry oxygen at 5 × 10−4 Torr in situ. Our initial analysis on the nucleation and growth of these three-dimensional Cu2O islands agrees well with the heteroepitaxial model of surface diffusion of oxygen.

Enhanced Nucleation and Decreased Growth Rates of Cu2O in Cu0.5Au0.5 (001) Thin Films During in situ Oxidation

2005 ◽  
Vol 20 (7) ◽  
pp. 1902-1909 ◽  
Author(s):  
Liang Wang ◽  
Judith C. Yang
Keyword(s):  
Lattice Mismatch ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Oxide Growth ◽  
Inert Component ◽  
Initial Oxidation ◽  
In Situ Oxidation ◽  
Transmission Electron ◽  
Oxidation Behaviors

The initial oxidation behaviors of Cu–50 at.% Au (001) single-crystal thin film were studied by in situ ultra-high-vacuum transmission electron microscopy to model nano-oxidation of alloys with one oxidizing component and one inert component. The oxidation behaviors such as incubation time, oxide nucleation rate, oxide growth kinetics as well as nucleation activation energy were greatly changed by the addition of nonoxidizing Au. The reasons for these changes, such as Au segregation to the top surface, a decrease in Cu activity, and reduced lattice mismatch due to the addition of Au, were discussed, and a qualitative analysis of nucleation energetics was given.

Anomalous Desorption of Copper Oxide Observed by In Situ Transmission Electron Microscopy

1997 ◽  
Vol 3 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Judith C. Yang ◽  
Mark Yeadon ◽  
Deirdre Olynick ◽  
J. Murray Gibson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cuprous Oxide ◽  
Copper Film ◽  
Copper Oxides ◽  
Simultaneous Exposure ◽  
Methanol Vapor ◽  
Transmission Electron ◽  
Thin Copper Film

Abstract: Here we present our observations of an anomalous desorption of copper oxides from a thin copper film during annealing as observed in an in situ transmission electron microscope. The epitaxial cuprous oxide that formed in air was observed to disappear when the specimen was annealed at 300°C and 10−8 torr. However, removal of the cuprous oxide that formed during oxidation in the microscope required both heating at 300°C and simultaneous exposure to methanol vapor.

Role of boundaries in the crystallization of amorphous films

1988 ◽  
Vol 46 ◽  
pp. 626-627
Author(s):  
D. A. Smith
Keyword(s):  
Low Temperature ◽  
Amorphous State ◽  
Nucleation And Growth ◽  
Amorphous Films ◽  
Island Nucleation ◽  
Surface Steps ◽  
Transmission Electron ◽  
Component Systems ◽  
Temperature Deposition

The nucleation and growth processes which lead to the formation of a thin film are particularly amenable to investigation by transmission electron microscopy either in situ or subsequent to deposition. In situ studies have enabled the observation of island nucleation and growth, together with addition of atoms to surface steps. This paper is concerned with post-deposition crystallization of amorphous alloys. It will be argued that the processes occurring during low temperature deposition of one component systems are related but the evidence is mainly indirect. Amorphous films result when the deposition conditions such as low temperature or the presence of impurities (intentional or unintentional) preclude the atomic mobility necessary for crystallization. Representative examples of this behavior are CVD silicon grown below about 670°C, metalloids, such as antimony deposited at room temperature, binary alloys or compounds such as Cu-Ag or Cr O2, respectively. Elemental metals are not stable in the amorphous state.

A TEM study of the microstructure of avian eggshells

1992 ◽  
Vol 50 (2) ◽  
pp. 1102-1103
Author(s):  
S. Q. Xiao ◽  
S. Baden ◽  
A. H. Heuer
Keyword(s):  
Electron Microscope ◽  
Calcium Carbonate ◽  
Nucleation And Growth ◽  
Growth Mechanisms ◽  
Shell Surface ◽  
Thin Sections ◽  
Polycrystalline Metals ◽  
Transmission Electron ◽  
Nucleation And Growth Mechanisms

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.

In situ observation of the martensitic transformation in (Mg,Y)-PSZ

1986 ◽  
Vol 44 ◽  
pp. 500-501
Author(s):  
R-R. Lee
Keyword(s):  
Martensitic Transformation ◽  
High Strength ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Considerable Potential ◽  
Transmission Electron ◽  
Structural Applications ◽  
Applied Stresses ◽  
Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

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