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.

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.

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.

scholarly journals Effect of the Sputtering Deposition Conditions on the Crystallinity of High-Temperature Annealed AlN Films

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 956
Author(s):  
Kenjiro Uesugi ◽  
Kanako Shojiki ◽  
Shiyu Xiao ◽  
Shigeyuki Kuboya ◽  
Hideto Miyake
Keyword(s):  
High Temperature ◽  
Chamber Pressure ◽  
Threading Dislocation ◽  
High Temperature Annealing ◽  
Oriented Growth ◽  
Sputtering Deposition ◽  
Face To Face ◽  
Aln Film ◽  
Before And After ◽  
Sputter Deposited

Face-to-face annealed sputter-deposited aluminum nitride (AlN) templates (FFA Sp-AlN) are a promising material for application in deep-ultraviolet light-emitting diodes (DUV-LEDs), whose performance is directly related to the crystallinity of the AlN film. However, the influence of the sputtering conditions and annealing on the crystallinity of AlN films have not yet been comprehensively studied. Accordingly, in this study, we fabricate AlN films on sapphire substrates through sputtering deposition followed by face-to-face high-temperature annealing, and investigate the influence of the sputtering conditions, such as the sputtering gas species and chamber pressure, on the crystallinity of the AlN films before and after annealing. The results revealed that reducing the amount of Ar in the sputtering gas significantly enhances the c-axis oriented growth during the initial stages of sputtering deposition and mitigates the tilt disorder of the layer deposited on the initial layer, resulting in low threading dislocation densities (TDDs) in the annealed AlN films. Decreasing the chamber pressure also effectively improves the crystallinity of the annealed AlN films. Thus, although high-temperature annealing can reduce the TDDs in AlN films, the properties of the as-sputtered AlN films have a significant effect on the crystallinity of FFA Sp-AlN films.

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.

Suppression of SiC surface roughening during high-temperature annealing by atmospheric control using purified Ar gas

2010 ◽  
Vol 25 (4) ◽  
pp. 708-710 ◽  
Author(s):  
Atsushi Ogura ◽  
Daisuke Kosemura ◽  
Shingo Kinoshita
Keyword(s):  
Surface Roughness ◽  
High Temperature ◽  
Surface Roughening ◽  
Annealing Atmosphere ◽  
High Temperature Annealing ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Furnace Tube ◽  
Ar Gas

4H-silicon carbide (SiC) wafers were annealed at 1300 and 1600 °C for 30 min and 60 min in a conventional and purified Ar atmosphere. The surface roughness before and after annealing was evaluated by atomic force microscopy. The surface roughness before annealing was approximately 2.37 nm in root mean square. The roughness, after annealing for 30 min at 1300 and 1600 °C in a conventional Ar furnace, was increased to 4.53 and 14.9 nm, respectively. The roughness, after annealing for 60 min, was 5.01 and 19.1 nm, respectively. In this study, the G3 grade Ar gas (99.999%) was supplied in the conventional furnace tube. When the Ar gas was purified to an impurity concentration of less than 1 ppb, and it was supplied in the leak-tight furnace tube, the roughness after 30-min annealing improved 4.27 and 6.93 nm at 1300 and 1600 °C, respectively. The roughness after 60-min annealing was also reduced to 3.54 and 9.28 nm, respectively. We assume that a significant reduction of H2O concentration in the annealing atmosphere might play an important role in suppressing surface roughening of SiC during high-temperature annealing.

Structural Relaxation of Amorphous Silicon Induced by High Temperature Annealing

1990 ◽  
Vol 205 ◽  
Author(s):  
L. De Wit ◽  
S. Roorda ◽  
W.C. Sinke ◽  
F.W. Saris ◽  
A.J.M. Berntsen ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Ion Implantation ◽  
Amorphous Silicon ◽  
Relaxation Process ◽  
Structural Relaxation ◽  
High Temperature Annealing ◽  
Temperature Range ◽  
Amorphous Si ◽  
Anneal Temperature

Structural relaxation of amorphous Si is studied in the temperature range 500-850 °C using Raman spectroscopy. The minumum value for the Raman peakwidth that can be obtained is inversely proportional to the anneal temperature. The relaxation process is basically the same in a-Si prepared by ion implantation and by vacuum evaporation.

Observation of Shrinking and Reformation of Shockley Stacking Faults by PL Mapping

2006 ◽  
Vol 527-529 ◽  
pp. 375-378 ◽  
Author(s):  
Toshiyuki Miyanagi ◽  
Hidekazu Tsuchida ◽  
Isaho Kamata ◽  
Tomonori Nakamura ◽  
R. Ishii ◽  
...  
Keyword(s):  
High Temperature ◽  
Laser Irradiation ◽  
High Power ◽  
Stacking Faults ◽  
High Temperature Annealing ◽  
High Power Laser ◽  
Power Laser ◽  
Before And After ◽  
Basal Plane Dislocation ◽  
Pl Mapping

We provide evidence of shrinking of Shockley-type stacking faults (SSFs) in the SiC epitaxial layer by high temperature annealing. Photoluminescence (PL) mapping in combination with high-power laser irradiation makes it possible to investigate the formation of SSFs, which lie between a pair of partial dislocations formed by dissociation of a basal plane dislocation (BPD), without fabrication of pin diodes. Using this technique, we investigated the annealing effect on SSFs. Comparing before and after annealing at 600°C for 10 min, it became obvious that high-temperature annealing results in shrinking of the faulted area of the SSFs. The SSFs form into the same features as those before annealing when high-power laser irradiation is performed again on the same area. This result shows that the faulted area of SSFs shrinks by 600°C annealing but the nuclei of SSFs (BPDs) do not disappear.

High Temperature Functionalization and Surface Modification of Nanodiamond Powders

2007 ◽  
Vol 1039 ◽  
Author(s):  
Vadym N. Mochalin ◽  
Sebastian Osswald ◽  
Cristelle Portet ◽  
Gleb Yushin ◽  
Christopher Hobson ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Phase Composition ◽  
High Temperature ◽  
Surface Chemistry ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
High Temperature Annealing ◽  
Treatment Techniques ◽  
Infra Red ◽  
Potential Applications

AbstractHigh temperature annealing in vacuum, air, hydrogen, chlorine, and ammonia are described as a means to change surface chemistry and phase composition of nanodiamond powders of three different grades, which have different sp2/sp3 carbon ratios. The changes in surface chemistry and phase composition of the powders are analyzed using Raman spectroscopy and Fourier Transform Infra Red (FTIR) spectroscopy. Advantages and limitation of high-temperature treatment techniques as well as potential applications of the gas-treated nanodiamond powders are discussed.

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