LOW-Temperature Epitaxial Growth of GaAs on Si Substrates by MBE

1992 ◽  
Vol 263 ◽  
Author(s):  
Ting-Yen Chiang ◽  
En-Huery Liu ◽  
Der-Hwa Yiin ◽  
Tri-Rung Yew
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Temperature ◽  
Epitaxial Growth ◽  
Defect Density ◽  
Solution Treatment ◽  
Plan View ◽  
Si Substrates ◽  
Gaas On Si ◽  
Transmission Electron

ABSTRACTThis paper presents results of the low—temperature epitaxial growth of GaAs on Si substrates with orientation 1°—4° off (100) by molecular beam epitaxy (MBE). The epitaxial growth ·is carried out on Si wafers subjected to HF solution treatment by “spin-etch” technique before the wafer is transferred to the entry chamber of MBE system. Methods used for reducing defect density in the epitaxial layers are proposed. The characterization techniques include cross-sectional transmission electron microscopy (XTEM), plan-view transmission electron microscopy, scanning electron microscopy (S EM), and double crystal X-ray diffraction (DCXRD). Epitaxial films with a full width at half—maximum (FWHM) of about 310 arcsec measured by DCXRD are obtained without annealing.-

scholarly journals Characterization of Gaas/Si/GaAs Heterointerfaces

1989 ◽  
Vol 148 ◽  
Author(s):  
Zuzanna Liliental-Weber ◽  
Raymond P. Mariella
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Temperature ◽  
Defect Density ◽  
Si Substrate ◽  
Reverse Polarity ◽  
Si Substrates ◽  
Transmission Electron ◽  
Metal Semiconductor Metal

ABSTRACTTransmission electron microscopy of GaAs grown on Si for metal-semiconductor-metal photodetectors is presented in this paper. Two kinds of samples are compared: GaAs grown on a 15 Å Si epilayer grown on GaAs, and GaAs grown at low temperature (300°C) on Si substrates. It is shown that the GaAs epitaxial layer grown on thin Si layer has reverse polarity to the substrate (antiphase relation). Higher defect density is observed for GaAs grown on Si substrate. This higher defect density correlates with an increased device speed, but with reduced sensitivity.

Direct Deposition Reactions Between Nickel and Silicon Substrates

1993 ◽  
Vol 311 ◽  
Author(s):  
Lin Zhang ◽  
Douglas G. Ivey
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Substrates ◽  
Silicide Formation ◽  
Cross Sectional ◽  
Deposition Rates ◽  
Plan View ◽  
X Ray ◽  
Si Substrates ◽  
Transmission Electron

ABSTRACTSilicide formation through deposition of Ni onto hot Si substrates has been investigated. Ni was deposited onto <100> oriented Si wafers, which were heated up to 300°C, by e-beam evaporation under a vacuum of <2x10-6 Torr. The deposition rates were varied from 0.1 nm/s to 6 nm/s. The samples were then examined by both cross sectional and plan view transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy and electron diffraction. The experimental results are discussed in terms of a new kinetic model.

TEM Study of the Growth Modes in ALMBE GaAs Layers on Si

1992 ◽  
Vol 281 ◽  
Author(s):  
A. Vilà ◽  
A. Comet ◽  
J. R. Morante ◽  
L. González ◽  
Y. González ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Epitaxial Growth ◽  
Deposition Temperature ◽  
Surface Coverage ◽  
Gaas On Si ◽  
Good Surface ◽  
Growth Modes ◽  
Transmission Electron

ABSTRACTIn this work, we have compared, by using Transmission Electron Microscopy (TEM) techniques, the initial stages of epitaxial growth of GaAs on Si (100) by conventional MBE and ALMBE, trying to find the conditions necessary to achieve 2D growth at the earliest stage of deposition. Our results show that flat layers with a good surface coverage can be obtained by reducing the GaAs ALMBE deposition temperature down to 200°C.

Replica observation by transmission electron microscopy of GaAs surface grown on vicinal Si (001)

1992 ◽  
Vol 50 (2) ◽  
pp. 1378-1379
Author(s):  
T. Inoue ◽  
Y. Kikuchi ◽  
T. Sasaki ◽  
T. Eshita ◽  
M. Yoshida
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Buffer Layers ◽  
Gaas Surface ◽  
Native Oxide ◽  
Si Substrates ◽  
Gaas On Si ◽  
Transmission Electron

Over the past several years, heteroepitaxy of GaAs on Si substrates has received strong interest because of its potential for monolithic integration of GaAs optical devices with Si integrated circuit technology. For heteroepitaxy of GaAs on Si substrate, Si(001) substrates oriented toward [110] by a few degrees (1) are used, therefore the GaAs epitaxial layer is expected to have a stepped surface. In this study, we characterized the GaAs surface, grown on vicinal Si(001 ) substrates, by replica observation using transmission electron microscopy (TEM).The Si substrates were oriented 2 degrees off towards [110] and their surface was expected to have a regular array of [110] steps, 8 nm apart. A two-step growth process (1) was employed to grow GaAs on Si(001) by metalorganic chemical vapor deposition (MOCVD). The Ga source was trimetyl gallium (TMG) and As source was AsH3. Following 10 minutes of 1000°C heat treatment in a H2, gas flow to remove the native oxide, 20 nm GaAs buffer layers were grown at 450°C. They were then heated to a growth temperature of 650°C to grow the GaAs epitaxial layers an additional 3 μm.

Defect investigation of GaN thin films etched by photo-electrochemical and hot wet etching by atomic force and transmission electron microscopy

2001 ◽  
Vol 680 ◽  
Author(s):  
P. Visconti ◽  
K. M. Jones ◽  
M. A. Reshchikov ◽  
R. Cingolani ◽  
H. Morkoç ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Density ◽  
Wet Etching ◽  
Hydride Vapor Phase Epitaxy ◽  
Structural Defects ◽  
Accurate Estimation ◽  
Plan View ◽  
Atomic Force ◽  
Transmission Electron

ABSTRACTThe availability of reliable and quick methods to investigate defects in GaN films is of great interest. Photo-electrochemical (PEC), and hot wet etching using both H3PO4 acid and molten KOH have been used to study structural defects in GaN layers grown by hydride vapor phase epitaxy and molecular beam epitaxy. The purpose of this work is to determine whether, and under what conditions, these different methods of investigation are consistent and to get to a more accurate estimation of the defect density. As-grown and etched surfaces were investigated by atomic force microscopy (AFM), and plan-view and cross-sectional transmission electron microscopy (TEM). Free-standing whisker-like features and hexagonal etch pits were formed on the etched sample surfaces by PEC and wet etching, respectively. Using plan-view AFM, we found the density of whiskers (8x108-1×109 cm−2) to be similar to the etch pit densities when etched in both H3PO4 and molten KOH under precise etching conditions. During the wet etching process, a careful balance must be struck to ensure that every defect is delineated, but not overetched to cause merging which would lead to an underestimation of the defect density. Additionally, TEM observations confirmed the dislocation densities obtained by etching, which increased our confidence in the consistency of the methods used.

Low-temperature annealing of YBa2Cu3O7-x

1992 ◽  
Vol 50 (1) ◽  
pp. 88-89
Author(s):  
R.L. Sabatini ◽  
Yimei Zhu ◽  
Masaki Suenaga ◽  
A.R. Moodenbaugh
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Temperature ◽  
Oxygen Diffusion ◽  
Diffusion Rate ◽  
Oxygen Depletion ◽  
Low Temperature Annealing ◽  
Transmission Electron ◽  
Microstructural Effects ◽  
Oxygen Diffusion Rate

Low temperature annealing (<400°C) of YBa2Cu3O7x in a ozone containing oxygen atmosphere is sometimes carried out to oxygenate oxygen deficient thin films. Also, this technique can be used to fully oxygenate thinned TEM specimens when oxygen depletion in thin regions is suspected. However, the effects on the microstructure nor the extent of oxygenation of specimens has not been documented for specimens exposed to an ozone atmosphere. A particular concern is the fact that the ozone gas is so reactive and the oxygen diffusion rate at these temperatures is so slow that it may damage the specimen by an over-reaction. Thus we report here the results of an investigation on the microstructural effects of exposing a thinned YBa2Cu3O7-x specimen in an ozone atmosphere using transmission electron microscopy and energy loss spectroscopy techniques.

Transmission Electron Microscopy characterization of epitaxial III-V semiconductor thin films grown on Si(100) by ion-assisted deposition

1990 ◽  
Vol 48 (4) ◽  
pp. 686-687
Author(s):  
L. Hultman ◽  
C.-H. Choi ◽  
R. Kaspi ◽  
R. Ai ◽  
S.A. Barnett
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Irradiation ◽  
High Energy ◽  
Nucleation Mechanism ◽  
Layer By Layer ◽  
Extended Defect ◽  
Island Formation ◽  
Si Substrates ◽  
Transmission Electron

III-V semiconductor films nucleate by the Stranski-Krastanov (SK) mechanism on Si substrates. Many of the extended defects present in the films are believed to result from the island formation and coalescence stage of SK growth. We have recently shown that low (-30 eV) energy, high flux (4 ions per deposited atom), Ar ion irradiation during nucleation of III-V semiconductors on Si substrates prolongs the 1ayer-by-layer stage of SK nucleation, leading to a decrease in extended defect densities. Furthermore, the epitaxial temperature was reduced by >100°C due to ion irradiation. The effect of ion bombardment on the nucleation mechanism was explained as being due to ion-induced dissociation of three-dimensional islands and ion-enhanced surface diffusion.For the case of InAs grown at 380°C on Si(100) (11% lattice mismatch), where island formation is expected after ≤ 1 monolayer (ML) during molecular beam epitaxy (MBE), in-situ reflection high-energy electron diffraction (RHEED) showed that 28 eV Ar ion irradiation prolonged the layer-by-layer stage of SK nucleation up to 10 ML. Otherion energies maintained layer-by-layer growth to lesser thicknesses. The ion-induced change in nucleation mechanism resulted in smoother surfaces and improved the crystalline perfection of thicker films as shown by transmission electron microscopy and X-ray rocking curve studies.

TEM Characterization of As-Deposited and Annealed Ni/Al Multilayer Thin Film

2010 ◽  
Vol 16 (6) ◽  
pp. 662-669 ◽  
Author(s):  
S. Simões ◽  
F. Viana ◽  
A.S. Ramos ◽  
M.T. Vieira ◽  
M.F. Vieira
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Ion Beam ◽  
Microstructural Characterization ◽  
Multilayer Thin Films ◽  
Tem Analysis ◽  
Plan View ◽  
Transmission Electron

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.

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