Heteroepitaxy of CoSi2 on Patterned Si(100) Substrates

1995 ◽  
Vol 402 ◽  
Author(s):  
O. P. Karpenko ◽  
D. J. Eaglesham ◽  
S. M. Yalisove

AbstractThis study has addressed the effect of starting surface topography on the nucleation and growth of epitaxial siicide layers. CoSi2 layers were grown via the template technique on one-dimensionally patterned Si (100) substrates. These substrates contained mesa stripes, running parallel to Si[011], and exhibited either smoothly varying sinusoidal profiles, or a number of well defined Si Ihkl) facets. Conventional plan view and high resolution cross section transmission electron microscopy were used to analyze the films grown on these substrates. The orientation and morphology of the CoSi2 grains depend on the angle (θ), between the CoSi2 / Si interface normal and Si (100). High quality (100) oriented CoSi2 grew on the tops and bottoms of mesa structures, where θ < 5°, and formed atomically sharp interfaces with the substrate. In contrast, CoSi2 (110) and CoSi2 (221 ) grains nucleated along the sidewalls of the mesa structures. The CoSi2 (110) grains formed rough interfaces with the substrate and were terminated by regions of step bunching at the grain boundary / substrate triple points. CoSi2 (110) grains were most highly concentrated in regions where θ varied from 5° to 12°. Similarly, the CoSi2 (221 ) grains formed faceted (111) b-type silicide / substrate interfaces, and were most highly concentrated in regions where θ > 10°. These data suggest that double height steps, step bunches and facets on the substrate are related to the nucleation of misoriented silicide grains.

1989 ◽  
Vol 146 ◽  
Author(s):  
Ivo J.M.M. Raaijmakers ◽  
Leo J. van Ijzendoorn ◽  
Anton M.L. Theunissen ◽  
Ki-Bum Kim

ABSTRACTIt is known that thermal annealing of Ti and amorphous (α) Si first results in an amorphous silicide, after which the crystalline disilicide grows under diffusion control. The situation with respect to the reaction of Ti with crystalline (x) Si is much less clear. We have investigated the reaction of Ti with xSi with (high resolution) cross-section transmission electron microscopy and in-situ Rutherford backscattering spectroscopy. It is shown that an amorphous silicide can also be formed on crystalline Si. The presence of this amorphous silicide as a precursor to the C49TiSi2 phase is suggested to be an important issue in the nucleation and growth of the disilicide.


Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright

High-resolution transmission electron microscopy has proven to be very useful in direct detection of crystalline phases that exist over extremely small volumes, yielding information about structure, orientation, and, under appropriate circumstances, composition. In this paper, we report the detection of a crystalline phase in the tungsten-rich layer of an annealed 7 nm-period tungsten-carbon multilayer produced at the Center for X-Ray Optics at the Lawrence Berkeley Laboratory.The multilayers were prepared by dc magnetron sputtering at floating temperature. The argon sputter gas pressure was 0.0020 torr. Different techniques were employed to produce cross-section and plan-view samples for TEM. For cross-section samples, 70 bilayers of W and C were sputtered on semiconductor-grade Si (111) wafers. For plan-view samples, the substrates on which the multilayer was grown consisted of 3 mm-diameter 300-mesh copper microscope grids, mounted on glass slide with Crystalbond® vacuum adhesive. After a deposition of 4 bilayers of W-C, keeping the same sputtering parameters as those of the Si substrates to guarantee the same layer thicknesses, the glass slide was soaked in acetone to disolve the Crystalbond®, leaving the multilayer spanning the holes of the copper grids. Both the Si-substrate and copper-grid samples were annealed at 500°C for 4 hours under vacuum of 10−6 torr. The annealed Si-substrate sample was then prepared for cross-section by mechanical grinding, and ion milling in a cold stage at 5kV. The cross-section sample was studied in a JEOL JEM 200CX with ultrahigh resolution goniometer, with the eletron beam parallel to the [112] of the Si substrate. The plan-view sample was studied in a Philips 301 operating at 100kV.


2010 ◽  
Vol 16 (6) ◽  
pp. 662-669 ◽  
Author(s):  
S. Simões ◽  
F. Viana ◽  
A.S. Ramos ◽  
M.T. Vieira ◽  
M.F. Vieira

AbstractReactive multilayer thin films that undergo highly exothermic reactions are attractive choices for applications in ignition, propulsion, and joining systems. Ni/Al reactive multilayer thin films were deposited by dc magnetron sputtering with a period of 14 nm. The microstructure of the as-deposited and heat-treated Ni/Al multilayers was studied by transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) in plan view and in cross section. The cross-section samples for TEM and STEM were prepared by focused ion beam lift-out technique. TEM analysis indicates that the as-deposited samples were composed of Ni and Al. High-resolution TEM images reveal the presence of NiAl in small localized regions. Microstructural characterization shows that heat treating at 450 and 700°C transforms the Ni/Al multilayered structure into equiaxed NiAl fine grains.


2001 ◽  
Vol 78-79 ◽  
pp. 197-204
Author(s):  
Daisuke Takeuchi ◽  
Hideyuki Watanabe ◽  
Sadanori Yamanaka ◽  
Hidetaka Sawada ◽  
Hideki Ichinose ◽  
...  

2017 ◽  
Vol 897 ◽  
pp. 173-176 ◽  
Author(s):  
Takahiro Sato ◽  
Yuya Suzuki ◽  
Hiroyuki Ito ◽  
Toshiyuki Isshiki ◽  
Kuniyasu Nakamura

The recently developed multi directional scanning transmission electron microscopy (MD-STEM) technique has been applied to exactly determine the Burgers vector (b) and dislocation vector (u) of a threading mixed dislocation in a silicon carbide (SiC) as-epitaxial wafer. This technique utilizes repeated focused ion beam (FIB) milling and STEM observation of the same dislocation from three orthogonal directions (cross-section, plan-view, cross-section). Cross section STEM observation in the [1-100] viewing direction showed that the burgers vector have a and c components. Subsequent plan view STEM observation in the [000-1] direction indicated that the b=[u -2uuw] (u≠0 and w≠0). Final cross section STEM observation in the [11-20] direction confirmed that the dislocation was an extended dislocation, with the Burgers vector experimentally found to be b = [1-210]a/3 + [0001]c which decomposes into two partial dislocations of bp1 = [0-110]a/3 + [0001]c/2 and bp2 = [1-100]a/3 + [0001]c/2. The dislocation vector u is [-12-10]a/3 + [0001]c. This technique is an effective method to analyze the dislocation characteristics of power electronics devices.


2008 ◽  
Vol 1069 ◽  
Author(s):  
Hui Chen ◽  
Guan Wang ◽  
Michael Dudley ◽  
Zhou Xu ◽  
James. H. Edgar ◽  
...  

ABSTRACTA systematic study is presented of the heteroepitaxial growth of B12As2 on m-plane 15R-SiC. In contrast to previous studies of B12As2 on other substrates, including (100) Si, (110) Si, (111) Si and (0001) 6H-SiC, single crystalline and untwinned B12As2 was achieved on m-plane 15R-SiC. Observations of IBA on m-plane (1100)15R-SiC by synchrotron white beam x-ray topography (SWBXT) and high resolution transmission electron microscopy (HRTEM) confirm the good quality of the films on the 15R-SiC substrates. The growth mechanism of IBA on m-plane 15R-SiC is discussed. This work demonstrates that m-plane 15R-SiC is potentially a good substrate choice to grow high quality B12As2 epilayers.


1999 ◽  
Vol 564 ◽  
Author(s):  
J. Y. Phillip Wang ◽  
Hong Zhang ◽  
Imran Hashim ◽  
Girish Dixit ◽  
Fusen Chen

AbstractThis paper reports an extensive interfacial study of Cu deposited on Ta and TaN barrier layers. It has been reported that the Cu/Ta interface develops a uniform and thin amorphous layer at the interface upon thermal treatment[l]. However, our high resolution transmission electron microscopy (HRTEM) analysis shows atomically sharp interfaces for all conditions without any amorphous layer at the interfaces, especially for the ones which underwent one hour annealing at 400°C and 500°C. The “amorphization” effect is only observed if the Cu/Ta TEM specimen is exposed to oxygen. It exists usually at the thinner regions of the TEM specimen or if the specimen is left in air for > 24 hours. Energy dispersion x-ray (EDX) analysis of the “amorphized” region shows that it is a mixture of Cu, Ta, and O.


2003 ◽  
Vol 18 (1) ◽  
pp. 14-26 ◽  
Author(s):  
D. Eyidi ◽  
M. D. Croitoru ◽  
O. Eibl ◽  
R. Nemetschek ◽  
W. Prusseit

CeO2 films are technologically important as buffer layers for the integration of superconducting YBa2Cu3O7−δ films on {100}-biaxially textured Ni substrates, yielding a Ni–CeO2–YBa2Cu3O7−δ layer sequence. The Ni–CeO2 interface is a metal–oxide interface, and the misfit between substrate and film is about 9%. An epitaxial growth model was suggested for this system in the literature. The investigated films were deposited by a reactive thermal evaporation process at substrate temperatures of 650–670 °C with a thickness of 100 nm after deposition. The CeO2 films were characterized by plan-view and cross-section transmission electron microscopy, atomic force microscopy, and scanning electron microscopy. The CeO2 films had a strong {100} biaxial texture with a roughness of approximately 90 nm. No intermediate layer could be found by cross-section transmission electron microscopy at the Ni–CeO2 interface. The films had columnar grains with diameters of 20–50 nm, much smaller than the grain size of the Ni substrate, which was larger than 1 μm. Small-angle grain boundaries and small amounts of 〈111〉-oriented grains were evidenced in plan-view samples by diffraction patterns. The Moiré fringes technique was applied and was ideally suited to image the small rotations (≤3°) of the small CeO2 grains with respect to the Ni substrate. These small rotations of small grains showed that the growth was nonepitaxial, however, biaxially textured. In the CeO2 film samples, nanovoids 5–10 nm in size were observed and were mostly located close to the film surface. A model for the growth of CeO2 thin films on nickel substrates can be proposed on the basis of our results.


1993 ◽  
Vol 8 (11) ◽  
pp. 2753-2756 ◽  
Author(s):  
L.B. Rowland ◽  
R.S. Kern ◽  
S. Tanaka ◽  
Robert F. Davis

Single-crystal epitaxial films of cubic β(3C)–SiC(111) have been deposited on hexagonal α(6H)–SiC(0001) substrates oriented 3–4° toward [1120] at 1050–1250 °C via gas-source molecular beam epitaxy using disilane (Si2H6) and ethylene (C2H4). High-resolution transmission electron microscopy revealed that the nucleation and growth of the β(3C)–SiC regions occurred primarily on terraces between closely spaced steps because of reduced rates of surface migration at the low growth temperatures. Double positioning boundaries were observed at the intersections of these regions.


1997 ◽  
Vol 04 (04) ◽  
pp. 687-694 ◽  
Author(s):  
KUNIO TAKAYANAGI ◽  
YOSHITAKA NAITOH ◽  
YOSHIFUMI OSHIMA ◽  
MASANORI MITOME

Surface transmission electron microscopy (TEM) has been used to reveal surface steps and structures by bright and dark field imaging, and high resolution plan view and/or profile view imaging. Dynamic processes on surfaces, such as step motion, surface phase transitions and film growths, are visualized by a TV system attached to the electron microscope. Atom positions can precisely be detected by convergent beam illumination (CBI) of high resolution surface TEM. Imaging of the atomic positions of surfaces with truncation is briefly reviewed in this paper, with recent development of a TEM–STM (scanning tunneling microscope) system.


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