scholarly journals Heteroepitaxial Growth of Ge Nanowires on Si Substrates

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Pietro Artoni ◽  
Alessia Irrera ◽  
Emanuele Francesco Pecora ◽  
Simona Boninelli ◽  
Corrado Spinella ◽  
...  
Keyword(s):  
Electron Beam ◽  
Lower Energy ◽  
Growth Conditions ◽  
Growth Direction ◽  
Electron Beam Evaporation ◽  
Heteroepitaxial Growth ◽  
Au Catalyst ◽  
Electron Microscopies ◽  
Si Substrates ◽  
Transmission Electron

Electron beam evaporation has been used to prepare Ge nanowires (NWs) on top of (111) Si substrates. Despite the non-UHV growth conditions, scanning and transmission electron microscopies demonstrate that NWs are single crystal with specific crystallographic growth directions ([111], [110], and [112]). NWs are faceted, exhibiting the lower energy plans on the surface. The faceting depends on the growth direction. Moreover, the detrimental effects for Ge NWs growth of O atoms contamination are discussed. Finally, we describe how a proper preparation of the Au catalyst is able to increase the Ge NW density by a factor of 4, while heteroepitaxy and faceting features are maintained.

Formation of Ge Nanocrystals in SiO2 by Electron Beam Evaporation

2008 ◽  
Vol 8 (2) ◽  
pp. 818-822 ◽  
Author(s):  
P. Basa ◽  
G. Molnár ◽  
L. Dobos ◽  
B. Pécz ◽  
L. Tóth ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Sheet Resistance ◽  
Electron Beam Evaporation ◽  
Nanocrystal Size ◽  
Cross Sectional ◽  
Si Substrates ◽  
Transmission Electron ◽  
Weber Type ◽  
Ge Nanocrystals

Ge nanocrystals were formed by electron beam evaporation on SiO2 covered Si substrates. The size and distribution of the nanocrystals were studied by atomic force microscopy, scanning electron microscopy and cross-sectional transmission electron microscopy. Dependencies of the nanocrystal size, of the nanocrystal surface coverage, and sheet resistance obtained by van der Pauw method of the Ge layer have been found on the evaporation time. The suggested growth mechanism for the formation of nanocrystals is the Volmer-Weber type. The sheet resistance exhibited a power dependence on the nanocrystal size.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

The Influence of the Carbonization Mechanisms on the Crystalline Quality of the Carbonization Layer for Heteroepitaxial Growth of 3C-SiC

2014 ◽  
Vol 778-780 ◽  
pp. 230-233
Author(s):  
Yukimune Watanabe ◽  
Tsuyoshi Horikawa ◽  
Kiichi Kamimura
Keyword(s):  
Diffusion Mechanism ◽  
Growth Direction ◽  
Crystalline Quality ◽  
Process Conditions ◽  
Heteroepitaxial Growth ◽  
Crystal Axis ◽  
Si Substrates ◽  
Selected Area Electron Diffraction ◽  
Better Than

The carbonized layer for a buffer layer strongly influences the crystalline quality of the 3C-SiC epitaxial films on the Si substrates. The growth mechanism of the carbonized layer strongly depended on the process conditions. The surface of silicon substrate was carbonized under the pressure of 7.8 × 10-3 Pa or 7.8 × 10-2 Pa in this research. Under the relatively low pressure of 7.8 × 10-3 Pa, the carbonized layer was grown by the epitaxial mechanism. The crystal axis of the carbonized layer grown under this pressure was confirmed to coincide with the crystal axis of the Si substrate from the results of the selected area electron diffraction (SAED) analysis. Under the relatively high pressure condition of 7.8 × 10-2 Pa, the carbonized layer was grown by the diffusion mechanism. The result of the SAED pattern and the XTEM image indicated that this layer consisted of small grainy crystals and their crystal axes inclined against the growth direction. It was confirmed that the crystalline quality of the SiC film deposited on the carbonized layer grown by the epitaxial mechanism is better than that deposited on the layer grown by the diffusion mechanism.

Chemistry, microstructure, and electrical properties at interfaces between thin films of cobalt and alpha (6H) silicon carbide (0001)

1995 ◽  
Vol 10 (1) ◽  
pp. 26-33 ◽  
Author(s):  
L.M. Porter ◽  
R.F. Davis ◽  
J.S. Bow ◽  
M.J. Kim ◽  
R.W. Carpenter
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Electrical Properties ◽  
Photoelectron Spectroscopy ◽  
Electron Beam Evaporation ◽  
Leakage Currents ◽  
X Ray ◽  
Transmission Electron

Thin films (4–1000 Å) of Co were deposited onto n-type 6H-SiC(0001) wafers by UHV electron beam evaporation. The chemistry, microstructure, and electrical properties were determined using x-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and I-V and C-V measurements, respectively. The as-deposited contacts exhibited excellent rectifying behavior with low ideality factors and leakage currents of n < 1.06 and 2.0 × 10−8 A/cm2 at −10 V, respectively. During annealing at 1000 °C for 2 min, significant reaction occurred resulting in the formation of CoSi and graphite. These annealed contacts exhibited ohmic-like character, which is believed to be due to defects created in the interface region.

Nanoscale Features Grown by MBE on Nonplanar Patterned Si Substrates

1995 ◽  
Vol 380 ◽  
Author(s):  
Karl D. Hobart ◽  
Fritz J. Kub ◽  
Henry F. Gray ◽  
Mark E. Twigg ◽  
Doewon Park ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Growth Parameters ◽  
Multiple Quantum ◽  
Electron Microscopies ◽  
Si Substrates ◽  
Transmission Electron ◽  
Low Dimensional ◽  
20 Nm ◽  
Nanoscale Features ◽  
Qualitative Changes

ABSTRACTSi growth by molecular beam epitaxy on nonplanar patterned Si substrates is studied as a function of growth parameters. The substrates consist of a truncated pyramid template with {111} sides and (100) tops formed by anisotropic etching of Si(100). For growth temperatures ≤ 550°C no qualitative changes in the morphology of the template are observed. At growth temperatures between 650–700°C {113} facets begin to form on the (100) surface and reduce the lateral dimensions of the (100) facet to < 20 nm. At high temperatures (∼800°C) {113} facets remain stable and {111} facets no longer exist. The small (100) mesa formed at medium temperatures by facet reduction is exploited through the growth of Si/Si 1-xGex multiple quantum wells leading to low-dimensional structures. Observations are quantified by scanning electron and transmission electron microscopies.

Heteroepitaxial Growth of Cubic Boron Nitride on Silicon

1992 ◽  
Vol 242 ◽  
Author(s):  
G. L. Doll ◽  
T. A. Perry ◽  
J. A. Sell ◽  
C. A. TAYLORS ◽  
R. Clarke
Keyword(s):  
Cubic Boron Nitride ◽  
Pulsed Laser ◽  
Growth Conditions ◽  
Critical Value ◽  
Laser Deposition ◽  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
Present Evidence ◽  
X Ray ◽  
Si Substrates

ABSTRACTNew x-ray diffraction measurements performed on bonm nitride films deposited by pulsed excimer laser deposition are presented. The x-ray data, taken with both a molybdenum rotating anode source and synchrotron radiation, indicate that the epitaxial cBN films are ≤ 200 Å thick. We also report the successful growth of oriented crystalline diamond on the (001) surface of cBN/Si substrates using the method of pulsed laser deposition. X-ray diffraction measurements indicate that the diamond layer is 200 Å thick with a lattice constant of 3.56 Å. The structures of metastable films (cBN and diamond) are very sensitive to growth conditions: we present evidence that an epitaxial-crystalline to incoherent phase transition occurs when the thickness of the films exceeds a critical value (∼ 200 Å for our present growth conditions).

Heteroepitaxial Growth and Faceting of Ge Nanowires on Si(111) by Electron-Beam Evaporation

2010 ◽  
Vol 13 (5) ◽  
pp. K53 ◽  
Author(s):  
Emanuele Francesco Pecora ◽  
Alessia Irrera ◽  
Pietro Artoni ◽  
Simona Boninelli ◽  
Corrado Bongiorno ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Beam Evaporation ◽  
Heteroepitaxial Growth

Microstructural studies by transmission electron microscopy of the formation of ultrathin PtSi layers with novel silicidation processes

1999 ◽  
Vol 14 (6) ◽  
pp. 2577-2587 ◽  
Author(s):  
S. Jin ◽  
H. Bender ◽  
R. A. Donaton ◽  
K. Maex
Keyword(s):  
Electron Beam ◽  
High Temperature ◽  
Thermal Annealing ◽  
Silicon Substrate ◽  
Growth Models ◽  
Schottky Diodes ◽  
Electron Beam Evaporation ◽  
Selective Etch ◽  
Transmission Electron ◽  
High Temperature Anneal

Ultrathin and uniform Pt-silicide layers are prepared by electron beam evaporation on a heated silicon substrate and by magnetron sputtering at room temperature followed by rapid thermal annealing (RTP) and selective etching, respectively. In the electron-beam deposited samples, continuous Pt-silicide layers of 6–8 nm thickness are formed after thermal annealing. The interfaces between the silicide layers and the silicon substrate are not atomically flat. In the case of the sputtered Pt, continuous PtSi layers down to 3 nm thick can be produced by using two-step (low-high temperature) and modified two-step (selective etch and high-temperature anneal) RTP silicidation processes. In one-step (high-temperature) processed samples, PtSi is the dominant phase; meanwhile, a small fraction of Pt12Si5 phase is inhomogeneously distributed in the case of thicker PtSi layers. In the two-step RTP processed samples, a Pt/Pt2Si/PtSi/Si layered structure is formed after the first RTP step. The first anneal step is found to be crucial for the roughness and epitaxy of the final PtSi layer. The best Schottky barrier heights are found to be 0.249 eV for the 3 nm PtSi/p-Si(100) Schottky diodes. The e-beam and the sputtered PtSi layers follow different epitaxial growth models.

Preparation and Characterization of Rare Rarth Scandate Thin Films as an Alternative gate dielectric

2006 ◽  
Vol 917 ◽  
Author(s):  
Martin Wagner ◽  
T. Heeg ◽  
J. Schubert ◽  
St. Lenk ◽  
C. Zhao ◽  
...  
Keyword(s):  
Thin Films ◽  
Electron Beam ◽  
Gate Dielectric ◽  
Rutherford Backscattering Spectrometry ◽  
Electrical Characterization ◽  
Electron Beam Evaporation ◽  
Silicon Substrates ◽  
Equivalent Thickness ◽  
X Ray ◽  
Transmission Electron

AbstractRare earth scandate thin films (GdScO3 and DyScO3) were investigated with respect to future high-k applications. They were deposited on (100) silicon substrates using either pulsed laser deposition (PLD) or electron beam evaporation. The investigation of the films was done by means of Rutherford backscattering spectrometry, high-temperature X-ray-diffractometry, X-ray reflectometry, spectroscopic ellipsometry, transmission electron microscopy (TEM) and atomic force microscopy. For the electrical characterization capacitor stacks were prepared. Both materials show very promising characteristics independent from the deposition technique used. The films are stoichiometric and amorphous and exhibit a smooth surface (roughness RMS < 1 Å). The amorphous phase is stable up to 1000°C. The electrical characterization revealed featureless C-V-curves with a small hysteresis. From CET plots (CET = capacitance equivalent thickness) k-values between 20 and 23 could be extracted. The electron beam evaporation produces films with a better homogeneity and a thinner interfacial silicon dioxide and therefore a smaller CET value as confirmed by TEM. The leakage current density of the film with CET = 1.5 nm was as low as 7.7x10-4 A/cm2.

scholarly journals GaN and InGaN Nanowires on Si Substrates by Ga-Droplet Molecular Beam Epitaxy

2008 ◽  
Vol 1080 ◽  
Author(s):  
Kevin Goodman ◽  
Kejia Wang ◽  
Xiangning Luo ◽  
John Simon ◽  
Tom Kosel ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Molecular Beam Epitaxy Growth ◽  
Growth Time ◽  
Band Edge Emission ◽  
Si Substrates ◽  
Gan Nanowires ◽  
Transmission Electron ◽  
Microscopy Images

ABSTRACTMolecular beam epitaxy growth of GaN and InGaN nanowires is accomplished on Si (111) substrates using Ga-droplet nucleation. Typical diameters range from 25-80 nm and lengths can be varied by increasing the growth time; the growth rate is ∼0.25 microns/hour. The nanowires have been characterized structurally and optically. Photoluminescence spectra show band-edge emission of GaN nanowires centered at 362 nm at 290 K. Transmission electron microscopy images unveil that the nanowires are highly crystalline, and grow along the 0001 polar direction. Indium has also been successfully incorporated into GaN nanowires by modifying the growth conditions; the InGaN nanowires emit at ∼520 nm, which provides a possible route to solving strain related problems of high In-composition InGaN based efficient green emitters.

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