The Formation and Annealing of Amorphous Layers of Al2O3

1985 ◽  
Vol 60 ◽  
Author(s):  
G. C. Farlow ◽  
P. S. Sklad ◽  
C. W. White ◽  
C. J. McHargue ◽  
B. R. Appleton
Keyword(s):  
Ion Irradiation ◽  
Amorphous Layer ◽  
Critical Dose

AbstractThe critical dose for formation of an amorphous layer of Al2O3 by ion irradiation at 77 K has been determined. It is found to lie between 2 and 3 × 1015/cm2 if the sample is irradiated near the <0001> axis of the substrate and is found to lie in the neighborhood of 2 × 1016/cm2 if the irradiation is near the <1210> axis. The amorphous layers are found to recrystallize epitaxially if annealed at 1190 degrees C and to form a metastable microstructure upon annealing at 800 degrees C.

scholarly journals Absence of single critical dose for the amorphization of quartz under ion irradiation

2017 ◽  
Vol 30 (1) ◽  
pp. 015403 ◽  
Author(s):  
S Zhang ◽  
O H Pakarinen ◽  
M Backholm ◽  
F Djurabekova ◽  
K Nordlund ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Critical Dose

Suppression of Martensitic Phase Transformation, Shape Memory and High Damping by Ion Implantation in Ni-Ti Thin Films

2006 ◽  
Vol 319 ◽  
pp. 17-24
Author(s):  
Rolf Gotthardt
Keyword(s):  
Phase Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Memory Effect ◽  
Ion Irradiation ◽  
Amorphous State ◽  
Amorphous Layer ◽  
Martensitic Phase ◽  
Martensitic Phase Transformation ◽  
Damping Capacity

The shape memory effect and the high damping in shape memory alloys are based on the martensitic phase transformation, which takes place essentially without diffusion and any change of order have an influence on its side effects: the memory effect, the superelasticity and the high damping capacity of the martensitic phase. A new method to control the performance of shape memory alloys is presented, which is based on selective modification of specified parts of working components. In this research, ion irradiation has been used to introduce locally disorder into a crystal or even amorphise it. A pre-deformed Ni-Ti, 6μm thin film in its martensitic state has been irradiated with Ni-ions of energy of 5 MeV up to a dose of 1016 ions/cm2. By this treatment, a 2μm thin surface layer has been finally transformed into an amorphous state, in which the martensitic transformation is suppressed. During heating the underlying non-modified layer is contracting and an out-of-plane movement is observed. The amorphous layer is elastically deformed and its energy is used during cooling to bring the film in its original shape. In this way, a reversible movement of the film is created. This new technique not only allows us to design new types of micro-actuators, but also to influence locally the high damping, which can be of great importance for micro-engineering applications.

Ion Beam Induced Amorphization and Crystallization Processes in Silicon and GaAs

1986 ◽  
Vol 74 ◽  
Author(s):  
R. G. Elliman ◽  
J. S. Williams ◽  
S. T. Johnson ◽  
E. Nygren
Keyword(s):  
Crystal Growth ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Amorphous Layer ◽  
Poor Quality ◽  
Layer By Layer ◽  
Epitaxial Crystallization ◽  
Non Linear ◽  
Thickness Layer

AbstractThin amorphous layers in crystalline Si and GaAs substates have been irradiated at selected temperatures with 1.5 MeV Ne+ ions to induce either epitaxial crystallization or amorphization. In Si, such irradiation can induce complete epitaxial crystallization of a 1000 A surface amorphous layer for temperatures typically >200°C whereas, at significantly lower temperatures, layer-by-layer amorphization results. Although epitaxial crystallization can also be stimulated in GaAs by ion irradiation at temperatures >65°C, the process is non-linear with ion dose and results in poor quality crystal growth for amorphous layers greater than a few hundred Angstroms in thickness. Layer-by-layer amorphization has not been observed in GaAs.

Amorphization of Silicon by Ion Irradiation: The Role of the Divacancy

1988 ◽  
Vol 100 ◽  
Author(s):  
R. G. Elliman ◽  
J. Linnros ◽  
W. L. Brown
Keyword(s):  
Activation Energy ◽  
Ion Irradiation ◽  
Amorphous Layer ◽  
Irradiation Temperature ◽  
Defect Production ◽  
Critical Flux ◽  
Defect Annealing ◽  
The Stability ◽  
Arrhenius Expression

ABSTRACTFixed fluence ion irradiation of silicon is shown to produce either defected crystal or amorphous silicon depending on the ion flux employed. The amorphous threshold flux, defined as the minimum flux required to generate a continuous amorphous layer for a fixed fluence irradiation, is measured as a function of irradiation temperature. This critical flux for amorphization is shown to satisfy an Arrhenius expression with a unique activation energy of ∼1.2eV, which corresponds to the migration/dissociation energy of the silicon divacancy. These observations lead to the conclusion that the stability of the silicon divacancy controls the competition between defect production and dynamic defect annealing, and hence the crystalline to amorphous phase transformation.

scholarly journals Microstructure and electrochemical properties of the HT-LiCoO2/La2/3–xLi3xTiO3 solid electrolyte interfaces

2010 ◽  
Vol 25 (8) ◽  
pp. 1583-1587 ◽  
Author(s):  
Kyosuke Kishida ◽  
Naoyuki Wada ◽  
Yuji Yamaguchi ◽  
Haruyuki Inui ◽  
Masahiko Demura ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Ion Irradiation ◽  
Lithium Ion ◽  
Amorphous Layer ◽  
Interface Structure ◽  
Cycle Stability ◽  
Surface Finishes ◽  
Lanthanum Titanate ◽  
Different Types ◽  
Lithium Ion Conductivity

Three different types of HT-LiCoO2/lithium lanthanum titanate (LLT) assemblies were produced by depositing an HT-LiCoO2 cathode on polycrystalline LLT with various surface finishes, to investigate the effects of the HT-LiCoO2/LLT interface structure on the electrochemical properties of the assemblies. An amorphous layer is confirmed to be introduced by Ar ion irradiation to crystalline LLT. The HT-LiCoO2/LLT assembly composed of the ion-irradiated LLT exhibits good cycle stability and relatively low apparent interface resistivity. These results indicate that the introduction of an amorphous LLT layer by surface modification of crystalline LLT is very effective in improving the structural stability and lithium-ion conductivity of the interface between HT-LiCoO2 and crystalline LLT.

Ion-Irradiation Study of the “Exotic” Mineral Neptunite: LiNa2K(Fe,Mg,Mn)2Ti2Si8O24

1990 ◽  
Vol 201 ◽  
Author(s):  
Ray K. Eby ◽  
L. M. Wang ◽  
G. W. Arnold ◽  
R. C. Ewing
Keyword(s):  
Surface Layer ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Amorphous Layer ◽  
Narrow Region ◽  
Transmission Electron ◽  
Room Temperature Aging ◽  
Transparent Region ◽  
Amorphous Surface ◽  
Temperature Aging

AbstractSingle crystals of the silicate neptunite were irradiated with 600 keV Ar2+ and 1.5 MeV Kr+ and analysed by transmission electron microscopy. Amorphization was observed in a surface layer several hundred angstroms thick following Ar2+ irradiations up to 5.0×l013 Ar/cm2, yet the Ar2+ ions travelled an average of 1/2 μm in depth. The microstructure of the amorphous surface layer depends on the ion fluence, but the amorphous layer thickness remained constant. At the highest fluence, a narrow region below the amorphous layer shows a brittle-to-ductile strain transition, due to tensional volume-expansion of the adjacent ductile amorphous layer. With 1.5 MeV Kr1+, amorphization of the electron transparent region was completed after a fluence of 1.7×l014 Kr+/cm2, and no further damage was observed up to 5.1×1015 Kr+/cm2. However, following a low fluence of 2.0×1011 Kr+/cm2, a single crystal of neptunite became a polycrystalline aggregate (grain size 10 nm) within 7 days of room temperature aging.

Corrosion behavior of Ni+ -Ion Irradiated NiTi Alloys

1983 ◽  
Vol 27 ◽  
Author(s):  
R. Wang ◽  
J. L. Brimhall
Keyword(s):  
Corrosion Behavior ◽  
Corrosion Potential ◽  
Ion Irradiation ◽  
Amorphous Layer ◽  
Amorphous Structure ◽  
Localized Corrosion ◽  
Corrosion Attack ◽  
Surface Conditions ◽  
Niti Alloys ◽  
Coarse Surface

ABSTRACTCorrosion behavior of Ni+ -irradiated NiTi alloys was studied in chloride solutions, together with unirradiated NiTi material with different surface conditions. Ion irradiation with either 2.5 or 5 MeV Ni+ ions transformed the NiTi surface into an amorphous layer up to 1.5 micrometers thick. Studies of corrosion potential vs. time and polarization behavior indicated a small enhancement of the passivation for the Ni+-irradiated NiTi over the unirradiated NiTi. The unirradiated NiTi with a mechanically polished, coarse surface was susceptible to pitting and crevice corrosion attack in 1 N HCl solution. The homogeneous amorphous structure in the irradiated alloy retarded this type of localized corrosion.

The Competition between Ion Beam Induced Epitaxial Crystallization and Amorphization in Silicon: The Role of the Divacancy

1986 ◽  
Vol 74 ◽  
Author(s):  
J. Linnros ◽  
R. G. Elliman ◽  
W. L. Brown
Keyword(s):  
Activation Energy ◽  
Dose Rate ◽  
Dynamic Equilibrium ◽  
Ion Beam ◽  
Amorphous Layer ◽  
Linear Displacement ◽  
Epitaxial Crystallization ◽  
Critical Dose ◽  
Ion Species

AbstractThe transition from ion induced epitaxial crystallization to planar amorphization of a preexisting amorphous layer in silicon has been investigated. The conditions for dynamic equilibrium at the transition were determined for different ion species as a function of dose rate and temperature. The critical dose rate for equilibrium varies exponentially with 1/T, exhibiting an activation energy of ∼1.2 eV. Furthermore, for different ions, the critical dose rate is inversely proportional to the square of the linear displacement density created by individual ions. This second order defect production process and the activation energy, which is characteristic of divacancy dissociation, suggest that the accumulation of divacancies at the amorphous/crystalline interface controls the balance between crystallization and amorphization.

Evolution of Semiconductor Thin Film and Surface Microstructure During Ion Bombardment

1990 ◽  
Vol 202 ◽  
Author(s):  
H. A. Atwater
Keyword(s):  
Thin Films ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Amorphous Layer ◽  
Misfit Strain ◽  
Crystal Nucleation ◽  
Microstructural Development ◽  
Complete Suppression ◽  
Semiconductor Films ◽  
Interface Motion

ABSTRACTDefects created by ion irradiation can enable new modes of microstructural development at interfaces and surfaces in semiconductor thin films. Two examples are described. First, novel kinetic paths for microstructural evolution via MeV ion beam modification of amorphous-crystal interface motion in Si are discussed. At intermediate temperatures, amorphous layer formation is initiated at interfaces such as surfaces and grain boundaries in polycrystalline Si. Irradiation at higher temperatures during the early stages of Si crystallization leads to a significant enhancement of the crystal nucleation rate, while nearly complete suppression of crystal nucleation during crystal growth can be achieved by a cyclic irradiation-induced amorphization and thermal growth process. Second, a new development in misfit strain accommodation in epitaxial semiconductor films is described in which ion-induced injection of point defect complexes can produce coherent, uniformly strained epitaxial thin films. Measurement of strain in epitaxial films can be used to distinguish between surface and sub-surface atomic displacements generated by a low energy ion beam.

Effect of Stress and Impurities on Preferential Amorphization on Grain Boundaries in Polycrystalline Silicon

1998 ◽  
Vol 540 ◽  
Author(s):  
Mitsuhiro Takeda ◽  
Somei Ohnuki ◽  
Seiichi Watanabe ◽  
Hiroaki Abe ◽  
Hiroshi Naramoto ◽  
...  
Keyword(s):  
Growth Rate ◽  
Grain Boundaries ◽  
Ion Irradiation ◽  
In Situ Observation ◽  
Constant Growth Rate ◽  
Second Stage ◽  
Critical Dose ◽  
Increasing Temperature ◽  
Constant Growth

AbstractClarifying the local amorphization on the grain boundaries, the in-situ observation during ion-irradiation was carried out for poly-crystalline Si film. The critical dose of amorphous formation increased exponentially with increasing temperature, where the local amorphization was developed at middle temperature. The critical dose was affected by the doped impurity and the grain size. The preferential amorphization on and near grain boundaries had two processes; first stage with rapid growth rate and second stage with almost constant growth rate. The importance of stress was demonstrated from the acceleration due to the stress on the first stage of amorphization.

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