Defect Model and Growth Characteristics of Low Temperature GaAs

1991 ◽  
Vol 241 ◽  
Author(s):  
M. Fatemi ◽  
B. Tadayon ◽  
H. B. Dietrich ◽  
S. Tadayon
Keyword(s):  
Low Temperature ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
Temperature Growth ◽  
X Ray ◽  
Random Behavior ◽  
Antisite Defects ◽  
Low Temperature Gaas ◽  
Lattice Matched

ABSTRACTLow-temperature GaAs layers (LTGaAs) grown by molecular beam epitaxy on GaAs substrates have been characterized by x-ray diffraction techniques. X-ray rocking curve measurements on more than 200 anneal conditions show that through appropriate choice of growth condition, layers with different states of strain are obtained. Three distinct ranges of low temperature growth are defined, labelled as “low-range,” “mid-range,” and “high-range,” corresponding to growth temperatures less than 260 °C, between 260 and 450 °C, and more than 450 °C, respectively. 0.5μm thick films grown in the low-range are amorphous, whereas those in the mid-range are fully strained and lattice-matched to the substrate, and those grown above 450 °C are indistinguishable from ordinary GaAs. Notable properties of mid-range layers are the random behavior of the as-grown strain, and the expansion and contraction of the lattice parameter with thermal anneals up to 900 °C. A growth model for LTGaAs based on arsenic antisite defects is proposed.

Precipitation of as in low-temperature MBE-grown gaas

1992 ◽  
Vol 50 (2) ◽  
pp. 1376-1377
Author(s):  
M. E. Twigg ◽  
M. Fatemi ◽  
B. Tadayon
Keyword(s):  
Low Temperature ◽  
Field Effect Transistors ◽  
Lattice Parameter ◽  
Buffer Layers ◽  
Double Crystal ◽  
Rocking Curve ◽  
Materials Properties ◽  
X Ray ◽  
Low Temperature Gaas ◽  
High Range

Recent work, on As rich GaAs buffer layers grown at low temperatures by molecular beam epitaxy (MBE), shows that this material has electronic and materials properties that differ from GaAs grown at higher temperatures. Among the interesting properties of these buffer layers are reduced recombination times and high breakdown voltages useful in power field effect transistors (FETs). We have used TEM, in conjunction with double crystal x-ray rocking curves, in studying GaAs grown and annealed at a variety of temperatures. X-ray rocking curve analysis has separated LT (low temperature) GaAs growth into three ranges of growth temperature: the “low-range” below 215°C, the “mid-range” from 215 to 340°C, and the “high-range” above 340°C. The low-range material is amorphous, as suggested by the presence of only the bulk reflections in the x-ray diffractometei profile and from HRTEM images of the MBE-grown buffer layer. The mid-range is single crystal and defect-free, although larger in lattice parameter than stoichiometric GaAs by as much as 0.08%.

Lattice parameter dependence versus composition in semiconductor alloys: the InGaAs case

2001 ◽  
Vol 677 ◽  
Author(s):  
C. Ferrari ◽  
E. Villaggi ◽  
N. Armani ◽  
G. Carta ◽  
G. Rossetto
Keyword(s):  
Linear Dependence ◽  
Lattice Parameter ◽  
Semiconductor Alloys ◽  
X Ray Diffraction ◽  
Diffraction Profile ◽  
X Ray ◽  
Inp Substrate ◽  
Dependence Versus ◽  
Parameter Versus ◽  
Lattice Matched

ABSTRACTFollowing recent works that report a non linear dependence of the lattice parameter versus composition in some semiconductor alloys the InGaAs/InP system has been investigated. The lattice parameter and the composition of InGaAs/InP lattice matched heterostructures have been independently determined by measuring the high resolution X-ray diffraction profile and the absorption of the X-ray beam diffracted from the InP substrate. In contrast with previous results that stated a linear dependence of the lattice parameter with composition, a 6% larger In content in the InGaAs/InP lattice matched alloy is found. Such result has been confirmed by the analysis of the X-ray fluorescence induced by an electron beam on the layer and on standards made of InAs and GaAs fine ground crystals. The result is in good agreement with the predictions of models based on the elasticity theory applied on a microscopic scale.

Chemical and Electrical Characterization of the CoGa/GaAs Interface as A Function of Temperature: A Thermally Stable Schottky Barrier up to 500°C

1992 ◽  
Vol 260 ◽  
Author(s):  
A. Alec Talin ◽  
Tue Ngo ◽  
R. Stanley Williams
Keyword(s):  
Schottky Barrier ◽  
Electrical Characterization ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Current Voltage ◽  
Lattice Matched ◽  
Better Than ◽  
Oriented Single Crystal

ABSTRACTX-ray diffraction studies and current-voltage measurements have been performed on a (100) oriented single crystal thin film of CoxGa1-x (x = 0.42) grown epitaxially on n-GaAs, from 300°C to 900°C. At this composition, CoxGa1-x, which has a broad range of homogeneity and a variable lattice parameter, is lattice matched to GaAs better than 0.5%. A Schottky barrier height of 0.68eV and an ideality factor of 1.07 have been measured up to 500°C, with significant barrier degradation at 600°C. At 700°C formation of the CoGa3 phase and a shift in CoxGa1-x stoichiometry to its bulk thermodynamically most stable composition of Co.45Ga.55 was observed with x-ray diffraction. At 800°C Co2AS formed, and at 900°C only CoGa3 and Co2As phases remained in contact with GaAs.

Growth and Properties of Lattice Matched GaAsSbN Epilayer on GaAs for Solar Cell Applications

2005 ◽  
Vol 891 ◽  
Author(s):  
Sudhakar Bharatan ◽  
Shanthi Iyer ◽  
Kevin Matney ◽  
Ward J. Collis ◽  
Kalyan Nunna ◽  
...  
Keyword(s):  
Low Temperature ◽  
Structural Changes ◽  
Ex Situ ◽  
Rf Plasma ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Energy ◽  
Localized Excitons ◽  
Matched Layers ◽  
Lattice Matched

ABSTRACTIn this work, the growth and characterization of GaAsSbN epilayers nearly lattice matched to GaAs, grown in an elemental solid source molecular beam epitaxy (MBE) system with a RF plasma nitrogen source, are discussed. The Sb and N compositions of the nearly lattice matched layers are 2.6% and 6.8%, respectively, as determined by high resolution x-ray diffraction (HRXRD) and secondary ion mass spectroscopy (SIMS) analysis. The layers are found to be fully strained as evidenced by the presence of Pendellosung fringes on the x-ray diffraction spectra.Effects of in-situ and ex-situ annealing on the low temperature photoluminescence (PL) characteristics are discussed. The 10 K PL peak energy of 1 eV with a FWHM of 18 meV has been achieved on ex-situ annealed samples in N ambient. The temperature dependence of PL peak energy exhibits “S-shaped” behavior in the low temperature regime, indicative of the presence of localized excitons. Raman spectroscopy analysis has been carried out to determine the local structural changes on annealing.

X-Ray Diffractometric Examination of Low-Temperature Phase Transformations in Single-Crystal Strontium Titanate

1963 ◽  
Vol 7 ◽  
pp. 136-145 ◽  
Author(s):  
Farrel W. Lytle
Keyword(s):  
Low Temperature ◽  
Single Crystal ◽  
Lattice Parameter ◽  
Temperature Curve ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Tetragonal Modification ◽  
X Ray ◽  
Line Splitting ◽  
Low Temperature Phase

AbstractThe lattice parameters of single-crystal SrTiO2 were determined by X-ray diffraction as a function of temperature from 4.2 to 300°K. Three significant regions were found: from 65 to 110°K a tetragonal modification, exists (c/a = 1.00056); from 35 to 55°K, line splitting consistent with orthorhornbic symmetry was observed, and at 10°K an anomalous maximum in the lattice parameter vs. temperature curve was found which suggested a third structure transformation. In the tetragonal region (at 78°K) the formation of a domain structure was observed with a polarising microscope. The low-temperature X-ray technique and X-ray cryostat are described.

Low-temperature growth of InGaN/GaN nano-islands investigated by grazing-incidence X-ray diffraction

2009 ◽  
Vol 6 (S2) ◽  
pp. S602-S606 ◽  
Author(s):  
Th. Schmidt ◽  
J. I. Flege ◽  
M. Siebert ◽  
S. Figge ◽  
T. Yamaguchi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Temperature Growth ◽  
X Ray ◽  
Low Temperature Growth

The Effect of Low Temperature GaAs Nucleation on the Growth of GaN on Silicon (001) During MOVPE Process

1997 ◽  
Vol 482 ◽  
Author(s):  
L. X. Zheng ◽  
J. W. Liang ◽  
H. Yang ◽  
J. B. Li ◽  
Y. T. Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
Atomic Layer ◽  
X Ray Diffraction ◽  
High Quality ◽  
Nucleation Layer ◽  
X Ray ◽  
Cubic Gan ◽  
Low Temperature Gaas

AbstractHigh quality cubic GaN was grown on Silicon (001) by metalorganic vapor phase epitaxy (MOVPE) using a GaAs nucleation layer grown at low temperature. The influence of various nucleation conditions on the GaN epilayers' quality was investigated. We found that the GaAs nucleation layer grown by atomic layer epitaxy (ALE) could improve the quality of GaN films by depressing the formation of mixed phase. Photoluminescence (PL) and X-ray diffraction were used to characterize the properties of GaN epilayers. High quality GaN epilayers with PL full width at half maximum (FWHM) of 130meV at room temperature and X-ray FWHM of 70 arc-min were obtained by using 10–20nm GaAs nucleation layer grown by ALE.

X-Ray Diffraction Studies of Low Temperature GaAs

1991 ◽  
Vol 241 ◽  
Author(s):  
G. Kowaljki ◽  
M. Leszcjynski ◽  
A. Kurpiewski ◽  
M. Kaminska ◽  
T. Suski ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Lattice Relaxation ◽  
Light Illumination ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Rocking Curve ◽  
X Ray ◽  
Large Lattice ◽  
Low Temperature Gaas ◽  
Substrate Temperatures

ABSTRACTGaAs layers grown by molecular beam epitaxy (MBE) at low substrate temperatures (LT GaAs) were studied in a novel purpose designed X-ray experiment. It combines X-ray double crystal rocking curve measurements with some elements usually found in optical setups like light illumination at liquid nitrogen temperatures applied to transfer EL2 type defects into metastable state. Ability to record such transfers with the X-ray experiment as well as large lattice relaxation accompanying this process is presented.

X-ray diffraction properties of curved crystal diffractors

1992 ◽  
Vol 50 (2) ◽  
pp. 1734-1735
Author(s):  
W. Z. Chang ◽  
D. B. Wittry
Keyword(s):  
Diffraction Theory ◽  
X Rays ◽  
Diffraction Image ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Bent Crystal ◽  
Diffraction Geometry ◽  
Crystal Parameter ◽  
Quantitative Procedure

Since Du Mond and Kirkpatrick first discussed the principle of a bent crystal spectrograph in 1930, curved single crystals have been widely utilized as spectrometric monochromators as well as diffractors for focusing x rays diverging from a point. Curved crystal diffraction theory predicts that the diffraction parameters - the rocking curve width w, and the peak reflection coefficient r of curved crystals will certainly deviate from those of their flat form. Due to a lack of curved crystal parameter data in current literature and the need for optimizing the choice of diffraction geometry and crystal materials for various applications, we have continued the investigation of our technique presented at the last conference. In the present abstract, we describe a more rigorous and quantitative procedure for measuring the parameters of curved crystals.The diffraction image of a singly bent crystal under study can be obtained by using the Johann geometry with an x-ray point source.

Micro X-Ray Diffraction Study of Polycrystalline MgB 2 Wire and Evaluation of Carbon Doping Effect Via Low-Temperature Sintering

2019 ◽  
Author(s):  
Minoru Maeda ◽  
Dipak Patel, Dr. ◽  
Hiroaki Kumakura, Dr. ◽  
Gen Nishijima, Dr. ◽  
Akiyoshi Matsumoto, Dr. ◽  
...  
Keyword(s):  
Low Temperature ◽  
Diffraction Study ◽  
Carbon Doping ◽  
Doping Effect ◽  
Low Temperature Sintering ◽  
X Ray Diffraction ◽  
X Ray
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