characterization of amorphization in Ni-Ti multilayers

1988 ◽  
Vol 46 ◽  
pp. 452-453
Author(s):  
K. B. Alexander ◽  
F. J. Walker ◽  
R. A. McKee ◽  
F. A. List
Keyword(s):  
Amorphous Film ◽  
High Energy ◽  
Film Deposition ◽  
Cross Sectional ◽  
Transmission Electron ◽  
20 Nm ◽  
Elemental Layer ◽  
Deposited Films

The formation of amorphous alloys through the solid-state reaction of crystalline multilayers has recently been studied by several groups. In each of these studies, the multilayers were entirely amorphous when there were less than 4-10 planes in each layer. Layer thicknesses larger than this resulted in crystalline layers, presumably separated by an amorphous film approximately 4-10 layers thick. Our intent was to measure the thickness of the amorphous film in Ni-Ti multilayer specimens with a wavelength (thickness of Ni + Ti layers) of 20 nm, or approximately 40 planes per elemental layer. In situ Reflection High Energy Electron Diffraction (RHEED) was performed during the film deposition and transmission electron microscopy of cross-sectional specimens was used to examine the as-deposited films.Nickel and titanium layers were sequentially deposited onto a 50 nm amorphous Ni-Ti codeposit on an unheated (001) silicon substrate in the ORNL Molecular Beam Epitaxy (MBE) facility with a vacuum < 10-9 torr.

In Situ Analysis of magnetic and Structural Properties of Epitaxial and Polycrystalline Ni80Fe20 Thin Films

1993 ◽  
Vol 313 ◽  
Author(s):  
I. Hashim ◽  
H.A. Atwater ◽  
Thomas J. Watson
Keyword(s):  
Magnetic Properties ◽  
Kerr Effect ◽  
High Energy ◽  
Epitaxial Films ◽  
Interface Roughness ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Transmission Electron

ABSTRACTWe have investigated structural and magnetic properties of epitaxial Ni80Fe20 films grown on relaxed epitaxial Cu/Si (001) films. The crystallographic texture of these films was analyzed in situ by reflection high energy electron diffraction (RHEED), and ex situ by x-ray diffraction and cross-sectional transmission electron Microscopy (XTEM). In particular, RHEED intensities were recorded during epitaxial growth, and intensity profiles across Bragg rods were used to calculate the surface lattice constant, and hence, find the critical epitaxial thickness for which Ni80Fe20 grows pseudomorphically on Cu (100). XTEM analysis indicated that the epitaxial films had atomically-abrupt interfaces which was not the case for polycrystalline Cu and Ni80Fe20 film interfaces. The Magnetic properties of these epitaxial films were Measured in situ using Magneto-optic Kerr effect magnetometry and were compared with those of polycrystalline films grown on SiO2/Si. Large Hc (∼ 35 Oe) was observed for epitaxial Ni80Fe20 films less than 3.0 nm thick whereas for increasing thickness, Hc decreased approximately monotonically to a few Oersteds. Correlations were made between magnetic properties of these epitaxial films, the strain in the film and the interface roughness obtained from XTEM analysis.

Orientational and Microstructural Evolution During Epitaxial Growth of Cu on Si(001) by Sputter Deposition

1992 ◽  
Vol 280 ◽  
Author(s):  
I. Hashim ◽  
B. Park ◽  
H. A. Atwater
Keyword(s):  
Epitaxial Growth ◽  
Ion Beam ◽  
High Energy ◽  
Sputter Deposition ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Plan View ◽  
Transmission Electron

ABSTRACTEpitaxial Cu thin films have been grown on H-terminated Si(OOl) substrates at room temperature by D.C. ion-beam sputter deposition in ultrahigh vacuum. The development of orientation and microstructure during epitaxial growth from the initial stages of Cu growth up to Cu thicknesses of few hundred nm has been investigated. Analysis by in-situ reflection high energy electron diffraction, thin film x-ray diffraction, and plan-view and cross-sectional transmission electron microscopy indicates that the films are well textured with Cu(001)∥ Si(001) and Cu[100]∥ Si[110]. Interestingly, it is found that a distribution of orientations occurs at the early stages of Cu epitaxy on Si(001) surface, and that a (001) texture emerges gradually with increasing Cu thickness. The effect of silicide formation and deposition conditions on the crystalline quality of Cu epitaxy is also discussed.

Epitaxial Growth of Silicon on CoSi2 (001)/Si (001)

1991 ◽  
Vol 220 ◽  
Author(s):  
Q. F. Xiao ◽  
J. R. Jimenez ◽  
L. J. Schowalter ◽  
L. Luo ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Growth Conditions ◽  
High Energy ◽  
Thin Layers ◽  
Ex Situ ◽  
High Crystalline Quality ◽  
Cross Sectional ◽  
Ion Channeling ◽  
Transmission Electron ◽  
Reconstructed Surface

ABSTRACTEpitaxial Si layers have been grown under a variety of growth conditions on CoSi2 (001) by molecular beam epitaxy (MBE). The structural properties of the Si overgrowth were studied by in-situ Reflection High Energy Electron Diffraction (RHEED), as well as ex-situ MeV4He+ ion channeling and High Resolution Transmission Electron Microscopy (HRTEM). Strong influences of the CoSi2 surface reconstruction on the Si overgrowth have been observed. RHEED studies show islanding growth of Si on the CoSi2 (001) (3/√2 × √2)R45 reconstructed surface, but smooth growth of Si on the CoSi2 (001) {√2 × √2)R45 reconstructed surface, under the same growth conditions. The growth of Si on thin layers of CoSi2 (2nm-6nm) with (√2 × √2)R45 reconstructed surface at 460°C results in high crystalline quality for the Si top layer, as indicated by good channeling minimum yield (Xmin < 6%), but cross-sectional TEM shows that the CoSi2 layers are discontinuous. We also report preliminary results on Si grown on a 2 × 2 reconstructed CoSi2 (001) surface.

In Situ Fabrication and Characterization of (NiCr)Al-Al2O3 Nanocomposite by Mechanical Alloying

2012 ◽  
Vol 16 ◽  
pp. 21-27 ◽  
Author(s):  
Amir Reza Shirani-Bidabadi ◽  
Ali Shokuhfar ◽  
Mohammad Hossein Enayati ◽  
Mazda Biglari
Keyword(s):  
Electron Microscopy ◽  
Mechanical Alloying ◽  
Structural Changes ◽  
Formation Mechanisms ◽  
Cross Sectional ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Powder Particles

In this research, the formation mechanisms of a (NiCr)Al-Al2O3 nanocomposite were investigated. The structural changes of powder particles during mechanical alloying were studied by X-ray difractometry (XRD) and the morphology and cross sectional microstructure of powder particles were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The methodology involved mechanical alloying of NiO, Cr, and Al with molar ratios of 3:3:8. During mechanical alloying, NiO was first quickly reduced by aluminum atoms to produce NiAl nanocrystalline and Al2O3. Subsequently, and when a longer milling time was applied, chromium atoms diffused into the NiAl lattice. The heat treatment of this structure led to the formation of the (NiCr)Al intermetallic compound as well as Al2O3 with crystalline sizes of 23 nm and 58 nm, respectively.

A TEM study of low-temperature Ge growth on Ge(001)2×1

1993 ◽  
Vol 51 ◽  
pp. 804-805
Author(s):  
H.Z. Xiao ◽  
G. Xue ◽  
I.M. Robertson ◽  
H.K. Birnbaum ◽  
J.E. Greene
Keyword(s):  
Low Temperature ◽  
High Energy ◽  
Group Iv ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Group Iv Semiconductors ◽  
Transmission Electron ◽  
And Control ◽  
Post Deposition

One approach to a solution of the doping problem in the molecular beam epitaxy (MBE) growth of the group IV semiconductors, e.g., segregation, low incorporation, and control of the dopants, is to lower the growth temperatures. It has been found that the room temperature Si deposition becomes amorphous after growth of a limiting epitaxial thickness which increases rapidly with the growth temperature. However, the mechanism for this structural transition is not well understood. In the present paper, we report the preliminary results of a study on the mechanism of the low temperature MBE growth of Ge on Ge(001)2×1 over the temperature range of 20-100 °C at deposition rates R=0.05 and 0.1 nm s−1 in an MBE system which has a bass pressure of 5xl0−11 Torr which increases to about 2xl0−9 Torr during deposition. The structural transitions were investigated using a combination of in-situ reflection high-energy electron diffraction (RHEED) and post-deposition high resolution cross-sectional transmission electron microscopy (XTEM).

Growth and Characterization of Si-GaP and Si-GaP-Si Heterostructures

1993 ◽  
Vol 334 ◽  
Author(s):  
N. Dietz ◽  
S. Habermehl ◽  
J. T. Kelliher ◽  
G. Lucovsky ◽  
K. J. Bachmann
Keyword(s):  
Epitaxial Growth ◽  
Chemical Beam Epitaxy ◽  
Si Substrate ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Amorphous Sic ◽  
Secondary Ion ◽  
Source Materials

AbstractThe low temperature epitaxial growth of Si / GaP / Si heterostructures is investigated with the aim using GaP as a dielectric isolation layer for Si circuits. GaP layers have been deposited on Si(100) surfaces by chemical beam epitaxy (CBE) using tertiarybutyl phosphine (TBP) and triethylgallium (TEG) as source materials. The influence of the cleaning and passivation of the GaP surface has been studied in-situ by AES and LEED, with high quality epitaxial growth proceeding on vicinal GaP(100) substrates. Si / GaP / Si heterostructures have been investigated by cross sectional high resolution transmission electron microscope (HRTEM) and secondary ion mass spectroscope (SIMS). These methods reveal the formation of an amorphous SiC interlayer between the Si substrate and GaP film due to diffusion of carbon generated in the decomposition of the metalorganic precursors at the surface to the GaP/Si interface upon prolonged growth (layer thickness > 300Å). The formation of twins parallel to {111} variants in the GaP epilayer are extended into the subsequently grown Si film with minor generation of new twins.

Prefabricated Metal Nanorods on Biaxially-Textured Templates on Flexible Substrates for REBCO Superconductors

2013 ◽  
Vol 23 (3) ◽  
pp. 6600705-6600705 ◽  
Author(s):  
Narayan Khatri ◽  
Goran Majkic ◽  
Renjie Wang ◽  
Aarthi Sundaram ◽  
Senthil Sambandam ◽  
...  
Keyword(s):  
Self Assembly ◽  
Spin Coating ◽  
Substrate Surface ◽  
High Energy ◽  
Film Deposition ◽  
Flexible Substrates ◽  
Pinning Centers ◽  
Flexible Metal ◽  
20 Nm

As an alternative to the introduction of flux pinning centers in RE-Ba-Cu-O (REBCO, RE = rare earth) films by the self-assembly process, we have explored prefabrication of metal nanorods on biaxially-textured templates on flexible substrates followed by REBCO film deposition. This approach provides an opportunity to control nanorod features such as size, shape, density, and orientation, which are difficult to achieve using self-assembly of nanoscale defects during in-situ growth. Successful growth of various metal nanorods such as Ni and Co on biaxially-textured substrates has been accomplished using high-energy ion bombardment of polycarbonate films for template formation followed by metal electrodeposition and polycarbonate removal. Ni nanorods of length up to 2 &#x03BC;m, diameter as small as 10-20 nm, variable orientation and density as high as 5 &#x00D7; 1010/cm2have been grown successfully on biaxially textured templates on flexible metal substrates. In order to provide a suitable interface between the metal nanorods and the subsequently deposited REBCO film, a strontium titanate (SrTiO3) film was deposited to the nanorods by solution spin coating, which was also (200) textured on the substrate surface.

An Electron Microscopic Characterization of Mbe-Grown ZnSe/CaAs and ZnSe/Ge Heterointerfaces

1990 ◽  
Vol 198 ◽  
Author(s):  
S.B. Sant ◽  
R.W. Smith ◽  
G.C. Weatherly
Keyword(s):  
Molecular Beam ◽  
Nucleation And Growth ◽  
Epitaxial Films ◽  
Defect Characterization ◽  
Initial Growth ◽  
Electron Microscopic ◽  
Cross Sectional ◽  
Transmission Electron

ABSTRACTMolecular beam epitaxy (MBE) grown ZnSe/GaAs and ZnSe/Ge heterointerfaces have been studied by transmission electron microscopy (TEM). Defect characterization of cross-sectional and planar specimens showed that ZnSe epitaxial films contain numerous twins that predominantly arise at the interface. Planar specimens of ZnSe/Ge were in-situ TEM annealed, for 5.5 hours at 873K. The twins are thermally very stable which would indicate that they arise during the growth process. The occurrence of these twins in the ZnSe film is explained by nucleation and growth of normal and twinned nuclei. Some of the ZnSe films grown on (10O)Ge substrates have low-angle boundaries indicating that the initial growth of the film is by the formation of islands.

Size and critical thickness evolution during growth of stacked layers of InAs/InP(001) quantum wires studied by in situ stress measurements

2003 ◽  
Vol 794 ◽  
Author(s):  
David Fuster ◽  
María Ujué González ◽  
Luisa González ◽  
Yolanda González ◽  
Teresa Ben ◽  
...  
Keyword(s):  
Critical Thickness ◽  
Quantum Wires ◽  
High Energy ◽  
In Situ Stress ◽  
Ex Situ ◽  
Stress Measurements ◽  
Transmission Electron ◽  
In Situ Stress Measurements ◽  
20 Nm

ABSTRACTSize and spatial distribution homogeneity of nanostructures is greatly improved by making stacks of nanostructures separated by thin spacers. In this work we present in situ and in real time stress measurements and reflection high energy electron diffraction (RHEED) observations and ex situ transmission electron microscopy (TEM) characterization of stacked layers of InAs quantum wires (QWr) separated by InP spacer layers, d(InP), of thickness between 3 and 20 nm. For d(InP) < 20 nm, the amount of InAs involved in the newly created QWr from the 2nd stack layer on, exceeds that provided by the In cell. Our results suggest that in those cases InAs 3D islands formation starts at the P/As switching and lasts during further InAs deposition. We propose an explanation for this process that is strongly supported on TEM observations. The results obtained in this work imply that concepts like the existence of a critical thickness for 2D-3D growth mode transition should be revised in correlated QWr stacks of layers.

In Situ High-Temperature Cross-Sectional TEM Specimen Preparation

1987 ◽  
Vol 115 ◽  
Author(s):  
Eric M. Fiore ◽  
Rodney A. Herring
Keyword(s):  
Phase Transformation ◽  
Electron Microscope ◽  
Thermal Processing ◽  
Defect Formation ◽  
High Energy ◽  
Formation Mechanisms ◽  
Specimen Preparation ◽  
Cross Sectional ◽  
Transmission Electron

ABSTRACTWe describe a technique for preparing transmission electron microscope (TEM) cross-sectional specimens for observation during in situ annealing to high temperatures. The process utilizes a ceramic adhesive that is stable to a temperature of 1650°C. The technique, which was successfully used to observe the recrystallization of amorphized silicon, is being applied to high-energy ion-implanted silicon in an attempt to better understand the amorphous-to-crystalline phase transformation and defect formation mechanisms resulting from thermal processing.

Sign in / Sign up

Export Citation Format

Share Document