Characterization of AlXGa1-xN Grown by MOCVD at Low Temperatures

1992 ◽  
Vol 242 ◽  
Author(s):  
Z. J. Yu ◽  
B. S. Sywe ◽  
J. H. Edgar
Keyword(s):  
Epitaxial Growth ◽  
Low Temperatures ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Sapphire Substrates ◽  
Electron Channelling ◽  
Temperature Deposition ◽  
Contrast Pattern

ABSTRACTThe low temperature deposition (400–650° C) of AlxGa1-xN films by metalorganic chemical vapor deposition (MOCVD) was characterized. Triethylgallium (TEG), trimethylaluminum (TMA), and ammonia (NH3) served as the precursors and both sapphire and silicon as the substrates with helium as the carrier gas. The deposition was operated at the atmospheric pressure. The crystallinity was improved even at low temperatures when AlxGal-xN was grown on a thin buffer layer of A1N at 400° C. With an AlxGa1-xN/AIN layered structure, epitaxial growth of AlxGa1-xN was obtained at 650° C on sapphire substrates. Auger results showed that the Al fraction x was less than 0.1. X-ray diffraction indicated a strong peak at 2θ =34.9 degrees for the (0002) planes from the film on sapphire substrates. The electron channelling pattern (ECP) of the film produced at 650° C revealed a 6 fold symmetry contrast pattern indicating the epitaxial growth of the film. Photoluminescence (PL) showed a dominant emission at 353 nm for the film on sapphire substrate. Surface morphology examined by SEM was featureless for the film produced at 500° C, while a relatively rough surface can be seen on the film produced at 650° C (5, 000x). The band gap was measured as 3.56 eV. The Al mole fraction x in the alloy was observed to be lower than that in the gas phase.

AlxGa1-xN-Based Materials and Heterostructures

1996 ◽  
Vol 449 ◽  
Author(s):  
P. Kung ◽  
A. Saxler ◽  
D. Walker ◽  
X. Zhang ◽  
R. Lavado ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Bragg Reflectors ◽  
X Ray Diffraction ◽  
Chemical Vapor Deposition Growth ◽  
X Ray ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Dimensional Electron Gas ◽  
P Type

ABSTRACTWe present the metalorganic chemical vapor deposition growth, n-type and p-type doping and characterization of AlxGa1-xN alloys on sapphire substrates. We report the fabrication of Bragg reflectors and the demonstration of two dimensional electron gas structures using AlxGa1-xN high quality films. We report the structural characterization of the AlxGa1-xN / GaN multilayer structures and superlattices through X-ray diffraction and transmission electron microscopy. A density of screw and mixed threading dislocations as low as 107 cm-2 was estimated in AlxGa1-xN / GaN structures. The realization of AlxGa1-xN based UV photodetectors with tailored cut-off wavelengths from 365 to 200 nm are presented.

Characterization of polycrystalline silicon carbide films grown by atmospheric pressure chemical vapor deposition on polycrystalline silicon

1998 ◽  
Vol 13 (2) ◽  
pp. 406-412 ◽  
Author(s):  
Christian A. Zorman ◽  
Shuvo Roy ◽  
Chien-Hung Wu ◽  
Aaron J. Fleischman ◽  
Mehran Mehregany
Keyword(s):  
Polycrystalline Silicon ◽  
Chemical Vapor ◽  
Deposition Process ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polycrystalline Silicon Carbide ◽  
Pressure Chemical ◽  
Temperature Deposition ◽  
Sic Films

X-ray diffraction, transmission electron microscopy, and Rutherford backscattering spectroscopy were used to characterize the microstructure of polycrystalline SiC films grown on as-deposited and annealed polysilicon substrates. For both substrate types, the texture of the SiC films resembles the polysilicon at the onset of SiC growth. During the high temperature deposition process, the as-deposited polysilicon recrystallizes without influencing the crystallinity of the overlying SiC. An investigation of the SiC/polysilicon interface reveals that a heteroepitaxial relationship exists between polysilicon and SiC grains. From this study, a method to control the orientation of highly textured polycrystalline SiC films has been developed.

Low-Temperature Deposition and Characterization of AlxIn1-xN Thin Films

1996 ◽  
Vol 449 ◽  
Author(s):  
Guohua Qiu ◽  
J. O. Olowolafe ◽  
Tao Peng ◽  
K. M. Unruh ◽  
C. P. Swann ◽  
...  
Keyword(s):  
Room Temperature ◽  
Chemical Vapor ◽  
Optical Measurements ◽  
Bandgap Energy ◽  
Nitride Semiconductors ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Temperature Deposition

ABSTRACTThin III-V nitride semiconductors fidms are commonly prepared using metalorganic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE). These methods often require high temperatures (800–1000°C) for the films to grow epitaxially. In the present work, we deposited AlxIn1-xN films on Si substrates by reactive magnetron sputttering method at low substrate temperature. The properties of the films have been studied by RBS, x-ray diffraction, and optical measurements. The AlxIn1-xN films deposited at room temperature were confirmed to be crystalline by x-ray diffraction. Band gap energies of our AlxIn1-xN alloys varies from 1.9 ev to 4.2 ev The bandgap energy vs. lattice constant curve was constructed and confirmed to bow downwards.

Effect of Argon during Diamond Deposition by Hot Filament Chemical Vapor Deposition

2016 ◽  
Vol 869 ◽  
pp. 721-726 ◽  
Author(s):  
Divani C. Barbosa ◽  
Ursula Andréia Mengui ◽  
Mauricio R. Baldan ◽  
Vladimir J. Trava-Airoldi ◽  
Evaldo José Corat
Keyword(s):  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
Gas Mixture ◽  
X Ray Diffraction ◽  
Hot Filament ◽  
Argon Content

The effect of argon content upon the growth rate and the properties of diamond thin films grown with different grains sizes are explored. An argon-free and argon-rich gas mixture of methane and hydrogen is used in a hot filament chemical vapor deposition reactor. Characterization of the films is accomplished by scanning electron microscopy, Raman spectroscopy and high-resolution x-ray diffraction. An extensive comparison of the growth rate values and films morphologies obtained in this study with those found in the literature suggests that there are distinct common trends for microcrystalline and nanocrystalline diamond growth, despite a large variation in the gas mixture composition. Included is a discussion of the possible reasons for these observations.

A Comparative Study of GaN Films Grown on Different Faces of Sapphire by ECR-Assisted MBE

1992 ◽  
Vol 242 ◽  
Author(s):  
T. D. Moustakas ◽  
R. J. Molnar ◽  
T. Lei ◽  
G. Menon ◽  
C. R. Eddy
Keyword(s):  
Surface Morphology ◽  
Low Temperatures ◽  
Smooth Surface ◽  
Growth Process ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
X Ray ◽  
Sapphire Substrates ◽  
Growth Method ◽  
Step Growth

ABSTRACTGaN films were grown on c-plane (0001), a-plane (1120) and r-plane (1102) sapphire substrates by the ECR-assisted MBE method. The films were grown using a two-step growth process, in which a GaN buffer is grown first at relatively low temperatures and the rest of the film is grown at higher temperatures. RHEED studies indicate that this growth method promotes lateral growth and leads to films with smooth surface morphology. The epitaxial relationship to the substrate, the crystalline quality and the surface morphology were investigated by RHEED, X-ray diffraction and SEM studies.

The Synthesis of Ce-Filled CoSb3 and Characterization of its Magnetic and Structural Properties

2003 ◽  
Vol 793 ◽  
Author(s):  
Arwyn L. E. Smalley ◽  
Brandon Howe ◽  
David C. Johnson
Keyword(s):  
Low Temperatures ◽  
Magnetic Measurements ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
X Ray ◽  
Ferromagnetic Component ◽  
Phase Pure ◽  
Powder Samples

ABSTRACTA series of cerium-containing CoSb3 samples were synthesized, with cerium quantities varying from 0 to 2 stoichiometric equivalents. These samples were annealed at low temperatures to crystallize the kinetically stable phases CexCo4Sb12 (x = 0–0.5). X-ray diffraction showed that these samples were phase pure, and Rietveld analysis on x-ray diffraction data from powder samples indicated that these samples were 25–88% crystalline. Electrical measurements showed that these samples are n-type, which was previously unknown in CexCo4Sb12. Magnetic measurements showed that the samples were paramagnetic due to the cerium being incorporated into the diamagnetic CoSb3 compound. In addition, they contained a ferromagnetic component that was attributed to the amorphous, cerium-containing phase.

Epitaxial Growth and Characterization of Nonpolar A-Plane AlGaN-Based Multiple Quantum Wells

2018 ◽  
Vol 934 ◽  
pp. 8-12
Author(s):  
Jian Guo Zhao ◽  
Xiong Zhang ◽  
Jia Qi He ◽  
Shuai Chen ◽  
Zi Li Wu ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Chemical Vapor ◽  
Multiple Quantum Wells ◽  
Modulation Method ◽  
Duty Ratio ◽  
Organic Chemical ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Metal Organic

A serious of non-polar a-plane AlGaN-based multiple quantum wells (MQWs) were successfully grown on the semi-polar r-plane sapphire substrate with metal organic chemical vapor deposition technology. Intense MQWs-related emission peaks at an emission wavelength covered from 277-294 nm were observed based on the photoluminescence measurement. It was found that the employment of the trimethyl-aluminum (TMAl) flow duty-ratio modulation method which was developed based on the two-way pulsed-flows growth technique played a crucial role to control the Al composition of the non-polar a-plane AlGaN epi-layers. The non-polar a-plane AlGaN-based MQWs were deposited with the new developed TMAl flow duty-ratio modulation technique. Evident-3th order X-ray diffraction (XRD) satellite peak was observed from the high resolution-XRD measurement, proving the successful growth of non-polar a-plane AlGaN-based MQWs with abrupt hetero-interfaces.

In situ characterization of strain-induced crystallization of natural rubber by synchrotron radiation wide-angle X-ray diffraction: construction of a crystal network at low temperatures

Soft Matter ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 734-743 ◽  
Author(s):  
Pinzhang Chen ◽  
Jingyun Zhao ◽  
Yuanfei Lin ◽  
Jiarui Chang ◽  
Lingpu Meng ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Structural Evolution ◽  
X Ray Diffraction ◽  
In Situ Characterization ◽  
X Ray ◽  
Crystal Network ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

The structural evolution of NR during stretching at −40 °C and in the strain–temperature space.

Sign in / Sign up

Export Citation Format

Share Document