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).

Temperature Dependent Quasi-Periodic Facetting of AlAs Grown by MBE on (100) GaAs Substrates

1993 ◽  
Vol 312 ◽  
Author(s):  
Richard Mirin ◽  
Mohan Krishnamurthy ◽  
James Ibbetson ◽  
Arthur Gossard ◽  
John English ◽  
...  
Keyword(s):  
Growth Conditions ◽  
High Energy ◽  
High Energy Electron ◽  
Temperature Dependent ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Atomic Force ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Facet Formation

AbstractHigh temperature (≥ 650°C) MBE growth of AlAs and AlAs/GaAs superlattices on (100) GaAs is shown to lead to quasi-periodic facetting. We demonstrate that the facetting is only due to the AlAs layers, and growth of GaAs on top of the facets replanarizes the surface. We show that the roughness between the AlAs and GaAs layers increases with increasing number of periods in the superlattice. The roughness increases to form distinct facets, which rapidly grow at the expense of the (100) surface. Within a few periods of the initial facet formation, the (100) surface has disappeared and only the facet planes are visible in cross-sectional transmission electron micrographs. At this point, the reflection high-energy electron diffraction pattern is spotty, and the specular spot is a distinct chevron. We also show that the facetting becomes more pronounced as the substrate temperature is increased from 620°C to 710°C. Atomic force micrographs show that the valleys enclosed by the facets can be several microns long, but they may also be only several nanometers long, depending on the growth conditions.

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.

Low Temperature in Situ Cleaning of Si(100) Surfaces and Transmission Electron Microscopy of Subsequent Growth of Epitaxial Germanium

1988 ◽  
Vol 116 ◽  
Author(s):  
R.A. Rudder ◽  
S.V. Hattangady ◽  
J.B. Posthill ◽  
R.J. Markunas
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Temperature ◽  
Carbonaceous Material ◽  
High Energy ◽  
Wafer Surface ◽  
Hydrogen Treatment ◽  
Heteroepitaxial Growth ◽  
Transmission Electron

AbstractA low temperature process for cleaning Si(100) surfaces has been developed. It involves a combination of a modified hot RCA wet chemistry treatment and an in situ hydrogen treatment for the removal of oxides and carbonaceous material from the Si surface. While this treatment is successful in producing reflection high energy electron diffraction patterns which show 1/2-order reconstruction lines, subsequent Ge heteroepitaxial growth at 300°C contains a high density of microtwins. Transmission electron microscopy reveals that most of the microtwins do not propagate to the wafer surface. Furthermore, the Ge/Si interface is not abrupt, and there are regions that do not appear crystalline. This suggests that some contamination is still present on the Si(100) surface after the in situ hydrogen treatments.

Molecular Beam Epitaxical Growth of AlxGa1-xAs on non- Planar Patterned GaAs (100)

1989 ◽  
Vol 145 ◽  
Author(s):  
S. Guha ◽  
A. Madhukar ◽  
K. Kaviani ◽  
Li Chen ◽  
R. Kuchibhotla ◽  
...  
Keyword(s):  
Migration Rate ◽  
Molecular Beam ◽  
Growth Front ◽  
In Situ Growth ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Quantum Well Structures ◽  
Transmission Electron ◽  
Front Profile

AbstractWe have examined some aspects of inter-facet migration during molecular beam epitaxical(MBE) growth of AlxGal-xAs on patterned GaAs (100) substrates. Scanning and cross-sectional transmission electron microscopy are employed to examine the evolution of the growth front profile. We observe significant inter facet migration from (3111/1411) facets which originate from the terrace edges to the flat terrace region. The migration length of cations on these facets is at least 0.9 μm for GaAs growth while for A10.5Ga0.5As it is less than 0.3 μm. We also observe a decreasing inter- facet migration rate with increasing growth. This interfacet migration is exploited for in situ, growth kinetics controlled, creation of laterally confined quantum well structures on the top terrace region and photoluminescence results for these structures are presented.

MeV Gold Ion Induced Sputtered Nanoparticles from Gold Nanostructures: Dependence of Incident Fluxand Temperature

2008 ◽  
Vol 8 (8) ◽  
pp. 4318-4321
Author(s):  
J. Ghatak ◽  
B. Sundaravel ◽  
K. G. M. Nair ◽  
P. V. Satyam
Keyword(s):  
Low Temperature ◽  
Size Distribution ◽  
Rutherford Backscattering Spectrometry ◽  
Bimodal Distribution ◽  
Heavy Ion ◽  
High Energy ◽  
Gold Nanostructures ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Surface And Interfaces

The high-energy and heavy-ion induced sputtered particles from nanostructures under various conditions can result in variety of size distributions. 1.5 MeV Au2+ ions induced sputtering from isolated gold nanostructures deposited on silicon substrate have been studied as a function of incident ion flux (dose rate) and the sputter particle catcher at low temperature. At higher fluxes, a bimodal distribution of the sputtered particles has been observed. Cross-sectional transmission electron microscopy and Rutherford backscattering spectrometry measurements showed that the sputter particle size distribution depends on morphology at surface and interfaces. The results for the size distribution from a catcher at low temperature showed the less agglomeration of ejected clusters on the catcher grids, resulting in the lower-disperse size distribution.

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.

Microstructural Characterization of Low Temperature GaAs(111)B MBE Growth by AFM and Tem

1992 ◽  
Vol 280 ◽  
Author(s):  
M. P. de Boer ◽  
J. E. Angelo ◽  
A. M. Dabiran ◽  
P. I. Cohen ◽  
W. W. Gerberich
Keyword(s):  
Low Temperature ◽  
Microstructural Characterization ◽  
Cross Sectional ◽  
Plan View ◽  
Mbe Growth ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Low Temperature Gaas

ABSTRACTAtomic Force Microscopy (AFM) images are correlated with Transmission Electron Microscopy (TEM) plan-view images in a structure consisting of <111> oriented GaAs layers grown by molecular beam epitaxy (MBE) at 500°C. We present results on the applicability of AFM, which requires short sample preparation and imaging time relative to TEM, in obtaining information on twin density and growth pits of these low temperature samples. Also, we discuss the behavior of twin boundaries by comparing plan-views and cross sectional TEM images.

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