Real Time Observations of Dislocation-Mediated Plasticity in the Epitaxial AI (011)/Si(100) Thin Film System

2000 ◽  
Vol 619 ◽  
Author(s):  
Eric A. Stach ◽  
U. Dahmen ◽  
W.D. Nix
Keyword(s):  
Strain Relaxation ◽  
Experimental Studies ◽  
Dislocation Motion ◽  
Metal Films ◽  
Silicon Substrates ◽  
Thermally Induced ◽  
Aluminum Films ◽  
Transmission Electron ◽  
Thin Aluminum

ABSTRACTDespite numerous theoretical and experimental studies of strain relaxation in metal films on silicon substrates, the exact mechanisms by which dislocations mediate plasticity in these structures are not well understood. To elucidate these mechanisms, we present results from in-situ transmission electron microscopy annealing of thin aluminum films grown on Si (100). As a model system, we have chosen to focus on aluminum films which contain two (011) epitaxial variants with respect to the silicon substrate. In this paper we discuss our observations of the glide and climb behavior of dislocations in these structures during thermal cycling. These observations give qualitative insight into the mechanisms by which dislocation motion accommodates thermally induced strains in thin metal films.

Relationship Between The Void And Hillock Formation And The Grain Growth In Thin Aluminum Films

1996 ◽  
Vol 428 ◽  
Author(s):  
O. V. Kononenko ◽  
V. N. Matveev
Keyword(s):  
Stress Relaxation ◽  
Grain Growth ◽  
The Self ◽  
Diffusion Creep ◽  
Silicon Substrates ◽  
Aluminum Films ◽  
Bias Stress ◽  
Transmission Electron ◽  
Thin Aluminum ◽  
Hillock Formation

AbstractVoid and hillock formation during annealing was studied depending on the deposition conditions. Aluminum films were deposited onto oxidized silicon substrates by the self-ion assisted technique. The bias 0 or 6 kV was applied to the substrate during deposition. The films were then annealed in vacuum for 1 hour in the temperature range from 1500 to 550°C. The structure of the films was investigated by transmission electron microscopy.It was found that recrystallization and void and hillock formation in the films depend on the bias during deposition. Normal grain growth occurred in the films deposited without bias. Abnormal grain growth was observed in the 6 kV-films. It was also found that the mechanism of stress relaxation during thermal cycling depends on the self-ion bombardment. In the films prepared without bias, stress relaxation proceeds by diffusion creep. In the films deposited at the 6 kV bias, stress relaxation proceeds by plastic deformation.

In situ transmission electron microscopy investigation of threading dislocation motion in passivated thin aluminum films

1999 ◽  
Vol 14 (12) ◽  
pp. 4673-4676 ◽  
Author(s):  
R-M. Keller-Flaig ◽  
M. Legros ◽  
W. Sigle ◽  
A. Gouldstone ◽  
K. J. Hemker ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dislocation Motion ◽  
Aluminum Film ◽  
Threading Dislocation ◽  
Cross Sectional ◽  
Aluminum Films ◽  
Transmission Electron ◽  
Microscopy Investigation

In situ transmission electron microscopy (TEM) was performed to study dislocation motion during temperature cycles in aluminum films passivated with a SiO2 layer. The films were cycled from room temperature to 450 °C. Wedge-haped cross-sectional TEM samples were used to retain the constraint of the Si substrate. Besides interactions between dislocations and interfaces, the movement of threading dislocations within the constrained aluminum film was observed. This observation provides an experimental corroboration of the occurrence of threading dislocation motion, which is the basis for rationalizing the high-ield strength of thin films in available models of thin-film plasticity.

scholarly journals Quantitative In-Situ Nanoindentation of Thin Films in a Transmission Electron Microscope

2001 ◽  
Vol 7 (S2) ◽  
pp. 912-913
Author(s):  
A.M. Minorl ◽  
E.A. Stach ◽  
J.W. Morris
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Real Time ◽  
Silicon Substrates ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Transmission Electron ◽  
Diamond Indenter ◽  
Force Calibration

A unique in situ nanoindentation stage has been built and developed at the National Center for Electron Microscopy in Berkeley, CA. By using piezoceramic actuators to finely position a 3-sided, boron-doped diamond indenter, we are able to image in real time the nanoindentation induced deformation of thin films. Recent work has included the force-calibration of the indenter, using silicon cantilevers to establish a relationship between the voltage applied to the piezoactuators, the displacement of the diamond tip, and the force generated.In this work, we present real time, in situ TEM observations of the plastic deformation of Al thin films grown on top of lithographically-prepared silicon substrates. The in situ nanoindentations require a unique sample geometry (see Figure 1) in which the indenter approaches the specimen normal to the electron beam. in order to meet this requirement, special wedge-shaped silicon samples were designed and microfabricated so that the tip of the wedge is sharp enough to be electron transparent.

Surface Cleaning Effects of Silicon Substrates by ECR Hydrogen Plasma on Subsequent Homoepitaxial Growth

2005 ◽  
Vol 475-479 ◽  
pp. 4067-4070
Author(s):  
Hyoun Woo Kim
Keyword(s):  
Electron Cyclotron Resonance ◽  
Substrate Surface ◽  
Hydrogen Plasma ◽  
Surface Cleaning ◽  
Silicon Substrates ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Defective Layer ◽  
Interfacial Oxygen

We have demonstrated the preparation of the almost defect-free homoepitaxial layer and the defective layer, respectively, with and without applying the in-situ cleaning of the silicon substrate surface using electron cyclotron resonance hydrogen plasma. Secondary ion mass spectroscopy indicated that the interfacial oxygen and carbon concentrations, respectively, decreased and increased with the in-situ cleaning. We have investigated the effect of process parameters such as microwave power, d.c bias, and cleaning time, on the epitaxial growth, by evaluating the cross-sectional transmission electron microscopy images of the subsequently deposited Si homoepitaxial film.

In-Situ Tem Investigation During Thermal Cycling of thin Copper Films

1996 ◽  
Vol 436 ◽  
Author(s):  
R.-M. Keller ◽  
W. Sigle ◽  
S. P. Baker ◽  
O. Kraft ◽  
E. Arzt
Keyword(s):  
Grain Growth ◽  
Room Temperature ◽  
Dislocation Motion ◽  
In Situ Tem ◽  
Copper Films ◽  
Stress Evolution ◽  
Cu Films ◽  
Transmission Electron ◽  
Insight Into

AbstractIn-situ transmission electron microscopy (TEM) was performed to study grain growth and dislocation motion during temperature cycles of Cu films with and without a cap layer. In addition, the substrate curvature method was employed to determine the corresponding stresstemperature curves from room temperature up to 600°C. The results of the in-situ TEM investigations provide insight into the microstructural evolution which occurs during the stress measurements. Grain growth occurred continuously throughout the first heating cycle in both cases. The evolution of dislocation structure observed in TEM supports an explanation of the stress evolution in both capped and uncapped films in terms of dislocation effects.

In Situ Electron Microscopy Studies of Surface Dynamical Processes

1998 ◽  
Vol 4 (S2) ◽  
pp. 608-609
Author(s):  
Ruud M. Tromp
Keyword(s):  
Electron Microscopy ◽  
Strain Relaxation ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Relaxation Phase ◽  
Transmission Electron ◽  
In Situ Electron Microscopy ◽  
Low Energy Electron ◽  
New Machine

To obtain a full and detailed understanding of the spatiotemporal dynamics of surface processes such as epitaxial growth, strain relaxation, phase transformations and phase transitions, chemisorption and etching, in situ real-time observations have proven to be invaluable. The development of two experimental techniques, i.e. Low Energy Electron Microscopy (LEEM) typically operating at electron energies below 10 eV, and Ultra-High-Vacuum Transmission Electron Microscopy (UHV-TEM) at several 100 keV, has made such in situ studies routinely possible. In many cases, the videodata obtained from such experiments are amenable to detailed, quantitative analysis, yielding statistical, kinetic and thermodynamic information that cannot be obtained in any other way.I will discuss recent experimental developments, including the design and construction of a new and improved LEEM instrument. Figure 1 shows a schematic diagram of this new machine. There are several features that distinguishes this design from most other LEEMs. One is the use of a 90 degree deflection magnetic prism array,

Investigations on the Aluminum/Para-Hexaphenyl Interface in Light Emitting Devices

1997 ◽  
Vol 488 ◽  
Author(s):  
N. Koch ◽  
L.-M. Yu ◽  
J.-L. Guyaux ◽  
Y. Morciaux ◽  
G. Leising ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Active Material ◽  
Direct Interaction ◽  
Metal Electrode ◽  
Insulating Layer ◽  
Aluminum Films ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Thin Aluminum

AbstractBlue light emitting devices (LED) with para-hexaphenyl (PHP) as the active material and aluminum as cathode exhibit very high quantum efficiencies. To further optimize device performance it is crucial to understand the physical properties of the involved interfaces. We have performed Rutherford-Backscattering experiments on actual devices to show the importance of oxygen in the interface formation at the cathode as this leads to the formation of a layer of AlxOy between PHP and aluminum. In devices, where the organic film is exposed to air before the metal electrode is evaporated, an insulating layer on the metal-side therefore is inherent. It has been shown that the introduction of an intermediate layer between active material and electrodes results in a higher quantum efficiency of the LED, the most common concepts being charge-transport-layers, or insulators on the other hand. Our results underline the need for a better control of the LED processing. Ultraviolet- and X-ray photoelectron spectroscopy in situ growth studies of thin aluminum films on PHP have been made to reveal the change in the electronic structure of the active medium in a LED in the absence of oxygen. Also the direct interaction of oxygen with this organic material is investigated by photoelectron spectroscopy.

The role of ion-beam cleaning in the growth of strained-layer epitaxial thin transition metal films

1987 ◽  
Vol 2 (4) ◽  
pp. 446-455 ◽  
Author(s):  
Sung I. Park ◽  
A. Marshall ◽  
R. H. Hammond ◽  
T. H. Geballe ◽  
J. Talvacchio
Keyword(s):  
Tunnel Junctions ◽  
Ion Beam ◽  
Surface Damage ◽  
Metal Films ◽  
Strained Layer ◽  
Transmission Electron ◽  
Lattice Matched

Low-energy ion-beam cleaning of the substrates prior to a deposition greatly enhances the quality of ultrathin (< 100 Å) refractory superconducting (Nb, V) films. Using this technique Nb films as thin as 7 Å have been grown, from which good tunnel junctions have been fabricated. Both the native films and the tunnel junctions are sturdy and can be thermally recycled without any degradation. In-situ surface study along with transmission electron microscopy (TEM) results suggest the removal of the carbon atoms from the surface of the substrate without an apparent surface damage as the causes of the improvement. The TEM results indicate that the Nb films grow perfectly lattice matched to the sapphire substrate when the substrate is ion-beam cleaned. This strained-layer epitaxy is observed up to 40 Å, the maximum thickness investigated through TEM.

Effect of Morphology on the Mobility of Nanosized Liquid Pb Inclusions in Solid Al

2007 ◽  
Vol 264 ◽  
pp. 55-62 ◽  
Author(s):  
S.I. Prokofjev ◽  
V.M. Zhilin ◽  
E. Johnson ◽  
U. Dahmen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Wide Temperature Range ◽  
Diffusion Coefficients ◽  
Temperature Range ◽  
Transmission Electron ◽  
Thin Aluminum

Diffusion of nanosized liquid Pb inclusions attached to dislocations in thin aluminum foils was investigated in a wide temperature range using in-situ transmission electron microscopy. Trajectories of motion of the inclusions along the dislocations were used to determine their diffusion coefficients. The temperature and size dependences of diffusion coefficients of the inclusions were obtained. They indicate that (i) studied inclusions hold {111} facets on their surface in the studied temperature range; (ii) the mobility of the inclusions is controlled by step nucleation at the {111} facets.

Phase Transformations in the Fe-Al System Studied by “In-Situ” Tem Heating

1994 ◽  
Vol 364 ◽  
Author(s):  
A. Korner
Keyword(s):  
Transition Temperature ◽  
Single Crystal ◽  
Domain Structure ◽  
Type A ◽  
Bimodal Distribution ◽  
Dislocation Motion ◽  
In Situ Tem ◽  
Transmission Electron ◽  
The Matrix

AbstractThe domain structure and the evolution of antiphase boundaries (APBs) have been investigated in Fe-Al by means of “in-situ” transmission electron microscopy (TEM) heating experiments. Single crystals with composition Fe22.1at%Al and Fe25.6at%Al have been used.The grown-in structure of the Fe22.1at%al single crystal is composed of DO3 ordered particles embedded in the disorderd ±-matrix. A bimodal distribution of the particles was found. Small ordered particles are in between the large precipitates which are surrounded by particle-free zones. Numerous of this large ordered precipitates contain APBs. Crossing the transition temperature to the disordered phase, the small particles dissolve into the ±-matrix and the large particles start to shrink by dissolving.The single crystal with composition Fe25.6at%Al was found to be completely DO3 ordered. The grown-in domains are separated by APBs of type a′0/2〈100〉. At temperatures far below the transition temperature to the B2 phase no significant change in the APB and domain structure has been detected. In contrast, a remarkable evolution in the APB structure has been observed approaching the transition temperature. Coarsening of the domains has been found. Furthermore, APBs of B2-type (a′0/4〈lll〉 shear) are dragged out by dislocation motion. B2- and DC3-type APBs react and junctions are formed. With increasing annealing time, the density of B2-type boundaries increases. The TEM image is dominated by B2-type boundaries linked by the D03-type boundaries. The DO3 superlattice spots are clearly excited approaching the transition temperature to B2. Above the transition temperature, the DO3 spots disappear completely and the diffraction pattern reveals B2 long range order.

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