A novel porous substrate for the growth of high quality GaN crystals by HVPE

RSC Advances ◽  
2014 ◽  
Vol 4 (66) ◽  
pp. 35106-35111 ◽  
Author(s):  
Yuanbin Dai ◽  
Yongzhong Wu ◽  
Lei Zhang ◽  
Yongliang Shao ◽  
Yuan Tian ◽  
...  
Keyword(s):  
Residual Stress ◽  
High Temperature ◽  
Defect Density ◽  
Annealing Process ◽  
High Temperature Annealing ◽  
Porous Substrate ◽  
High Quality

This manuscript describes a high temperature annealing process to prepare a porous substrate. The substrate was used for the growth of GaN by using HVPE method to provide reduced residual stress and low defect density.

High Temperature Annealing SP-AlN Ameliorates the Crystal Quality ofAl0.5Ga0.5N Regrowth

2020 ◽  
Vol 1014 ◽  
pp. 14-21
Author(s):  
Wen Kai Yue ◽  
Zhi Min Li ◽  
Xiao Wei Zhou ◽  
Jin Xing Wu ◽  
Pei Xian Li
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Annealing Process ◽  
High Temperature Annealing ◽  
High Quality ◽  
Rocking Curve ◽  
Stress Mode ◽  
Aln Film ◽  
Before And After ◽  
Screw Dislocation Density

In this study, the effect of a high-temperature annealing process on AlN is investigated. The high-temperature annealing process reduces the screw dislocation density of the AlN film to 2.1x107 cm-2. The AlN surface is highly flat. Through HRXRD and Raman spectroscopy, the stress mode changes in the sputtered AlN film before and after high-temperature annealing were studied in depth. Based on the HTA-AlN template, a high-quality, high-Al composition AlGaN epitaxial wafer, with a (0002) plane rocking curve FWHM of 246 arcsec , was prepared at 1080°C The growth mode of AlGaN grown directly on the AlN template at low temperature is summarized.

Low Dislocation Soi by Oxygen Implantation

1987 ◽  
Vol 107 ◽  
Author(s):  
A.H. Van Ommen
Keyword(s):  
High Temperature ◽  
Dislocation Density ◽  
Point Defects ◽  
Defect Density ◽  
Silicon Film ◽  
Silicon On Insulator ◽  
High Temperature Annealing ◽  
High Quality ◽  
To Come ◽  
Sharp Interfaces

AbstractRecent results on silicon on insulator structures formed by implantation of oxygen and subsequent high temperature annealing will be discussed. The resulting silicon on insulator structure has sharp interfaces and a dislocation density of less than 105 cm -2 in the top silicon film. This density of defects is several orders of magnitude lower than previously reported values. The relation between the microstructure after implantation and this relatively low defect density will be discussed. Silicon point defects will be shown to play an important role in the establishment of the microstructure during implantation. Relations between implantation conditions, point defect concentrations and microstructure will be discussed to come to the formulation of the boundary conditions for the formation of high quality silicon on insulator material by this method.

Four-inch high quality crack-free AlN layer grown on a high-temperature annealed AlN template by MOCVD

2021 ◽  
Vol 42 (12) ◽  
pp. 122804
Author(s):  
Shangfeng Liu ◽  
Ye Yuan ◽  
Shanshan Sheng ◽  
Tao Wang ◽  
Jin Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Flat Surface ◽  
Epitaxial Lateral Overgrowth ◽  
High Temperature Annealing ◽  
High Quality ◽  
High Crystalline Quality ◽  
X Ray ◽  
Lateral Overgrowth

Abstract In this work, based on physical vapor deposition and high-temperature annealing (HTA), the 4-inch crack-free high-quality AlN template is initialized. Benefiting from the crystal recrystallization during the HTA process, the FWHMs of X-ray rocking curves for (002) and (102) planes are encouragingly decreased to 62 and 282 arcsec, respectively. On such an AlN template, an ultra-thin AlN with a thickness of ~700 nm grown by MOCVD shows good quality, thus avoiding the epitaxial lateral overgrowth (ELOG) process in which 3–4 μm AlN is essential to obtain the flat surface and high crystalline quality. The 4-inch scaled wafer provides an avenue to match UVC-LED with the fabrication process of traditional GaN-based blue LED, therefore significantly improving yields and decreasing cost.

High-Quality SOI by Oxygen Implantation into Silicon

1987 ◽  
Vol 93 ◽  
Author(s):  
A. H. van Ommen ◽  
H. J. Ligthart ◽  
J. Politiek ◽  
M. P. A. Viegers
Keyword(s):  
High Temperature ◽  
Silicon Film ◽  
Silicon On Insulator ◽  
High Dose ◽  
High Temperature Annealing ◽  
High Quality ◽  
Cubic Symmetry ◽  
Buried Oxide ◽  
Simple Cubic ◽  
Precipitate Growth

ABSTRACTHigh quality Silicon-On-Insulator, with a dislocation density lower than 105cm−2, has been formed by high temperature annealing of high-dose oxygen implanted silicon. In the as-implanted state, oxygen was found to form precipitates in the top silicon film. In the upper region these precipitates were found to order into a superlattice of simple cubic symmetry. Near the interface with the buried oxide film the precipitates are larger and no ordering occurs in that region. Contrary to implants without precipitate ordering where dislocations are observed across the entire layer thickness of the top silicon film, dislocations are now only found near the buried oxide. The precipitate ordering appears to prevent the dislocations to climb to the surface. High temperature annealing results in precipitate growth in this region whereas they dissolve elsewhere. These growing precipitates pin the dislocations and elimination of precipitates and dislocations occurs simultaneously, resulting in good quality SOI material.

Influence of High Temperature Annealing in Nitrogen on Upconversion Luminescence of β-NaYF4: Yb3+, Er3+ Hexagonal Sub-Microplates

2012 ◽  
Vol 496 ◽  
pp. 79-83
Author(s):  
Jun Wei Zhao ◽  
Tie Kun Jia ◽  
Xiang Gui Kong
Keyword(s):  
High Temperature ◽  
Sodium Citrate ◽  
Hexagonal Phase ◽  
Upconversion Luminescence ◽  
Annealing Treatment ◽  
Annealing Process ◽  
High Temperature Annealing ◽  
Nonradiative Relaxation ◽  
Before And After ◽  
Hydrothermal Methods

The pure β-NaYF4: Yb3+, Er3+ hexagonal sub-microplates were successfully prepared by the combination of coprecipitation and hydrothermal methods using sodium citrate as chelator. The size of them is about 600 nm × 400 nm (side length × thickness). The obtained sample was divided into two parts and one of them was annealed in nitrogen at 300 °C for 2 hours. The crystal structure of the β-NaYF4: Yb3+, Er3+ hexagonal sub-microplates before and after annealing treatment is hexagonal phase. Under the excitation of 980 nm diode laser, the upconversion luminescence intensity the sample after annealing is much stronger than that of the sample without annealing treatment. High temperature annealing process improved the crystallization of the sample, resulting in the decrease of the nonradiative relaxation and the enhancement of the upconversion luminescence.

HOMO-EPITAXIAL GROWTH ON ZnO SUBSTRATE BY MO-CVD USING (C5H7O2)2

2007 ◽  
Vol 14 (04) ◽  
pp. 783-787 ◽  
Author(s):  
KOICH HAGA ◽  
TOETSU SHISHIDO ◽  
KAZUO NAKAJIMA ◽  
TAKAHIRO MATSUNAGA
Keyword(s):  
High Temperature ◽  
Photoelectron Spectroscopy ◽  
High Energy ◽  
Zno Films ◽  
High Temperature Annealing ◽  
High Quality ◽  
Ion Etching ◽  
Atomic Force ◽  
Good Crystallinity ◽  
Atomically Flat

High quality homo-epitaxial ZnO films were grown on Zn -terminated surfaces of ZnO (0001) single-crystal substrates with high-temperature annealing and Ar + ion etching. These films were prepared by low-pressure MO-CVD using zinc acetylacetonate ( C 5 H 7 O 2)2 and oxygen as source materials. High quality ZnO (0001) substrate was synthesized by the hydrothermal technique. The atomically flat surface without scratches was obtained by high temperature annealing at 800°C–1300°C in oxygen atmosphere. Ar + ion etching for the surface of ZnO substrates was critically important to the growth of ZnO films with good crystallinity. The epitaxial film and the ZnO substrate were characterized using reflection high-energy electron diffraction, atomic force microscope, and X-ray photoelectron spectroscopy.

PREVENTION OF SINTERING DURING ANNEALING PROCESS OF FePt NANOPARTICLES COATED WITH ZnO SHELL

NANO ◽  
2012 ◽  
Vol 07 (06) ◽  
pp. 1250043 ◽  
Author(s):  
HOSSEIN ZEYNALI ◽  
HOSSEIN AKBARI ◽  
REYHANEH KARIMI GHASABEH ◽  
S. ARUMUGAM ◽  
ZOHREH CHAMANZADEH ◽  
...  
Keyword(s):  
High Temperature ◽  
Zno Nanoparticles ◽  
Annealing Process ◽  
Oxide Shell ◽  
Fept Nanoparticles ◽  
Ferromagnetic Behavior ◽  
High Temperature Annealing ◽  
Narrow Size Distribution ◽  
Annealing Temperatures ◽  
Co Reduction

Monodispersed 4.1 nm FePt nanoparticles with narrow size distribution were successfully synthesized by the chemical polyol process with co-reduction of Fe (acac)3 and Pt (acac)2 in the presence of 1,2-hexadecanediol as a reducing agent. To achieve hard ferromagnetic behavior with L10 phase and face center tetragonal (fct) structure, high temperature annealing is performed. Annealing causes the surfactant surrounding particles to decompose and agglomeration of particles occurs. In the present work, chemically synthesized FePt nanoparticles were coated with nonmagnetic ZnO oxide shell to prevent them from sintering. Coercivity of FePt and FePt/ZnO nanoparticles increases from 5 kOe to 10 kOe and 1.8 kOe to 6 kOe respectively, with the increasing annealing temperatures from 650 to 750°C.

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