Characteristics of Fielo-GaN Grown by Hydride Vapor Phase Epitaxy

2000 ◽  
Vol 639 ◽  
Author(s):  
Akira Usui ◽  
Haruo Sunakawa ◽  
Kenji Kobayashi ◽  
Heiji Watanabe ◽  
Masashi Mizuta
Keyword(s):  
Electron Microscopy ◽  
Dislocation Density ◽  
Hydride Vapor Phase Epitaxy ◽  
Epitaxial Lateral Overgrowth ◽  
Rocking Curve ◽  
X Ray ◽  
Lateral Overgrowth ◽  
Dislocation Behavior ◽  
Reflection Electron Microscopy

ABSTRACTThe crystal quality of facet-initiated epitaxial lateral overgrowth (FIELO) -GaN, in particular, that in the vicinity of the GaN surface, is reported. It is shown that the surface smoothness of FIELO-GaN enables us to use it as an “epi-ready” substrate. The crystallinity of FIELO-GaN is evaluated by x-ray rocking curve (XRC) measurements. We indicate that the FWHM of XRC should be reduced with the decrease of the dislocation density. We previously reported that the dislocation behavior of FIELO-GaN causes the tilting of the c-axis in the overgrown regions. By using scanning reflection electron microscopy (SREM), however, we show that the tilting on the surface of thick FIELO-GaN was negligibly small.

scholarly journals Void Shapes Controlled by Using Interruption-Free Epitaxial Lateral Overgrowth of GaN Films on Patterned SiO2AlN/Sapphire Template

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yu-An Chen ◽  
Cheng-Huang Kuo ◽  
Li-Chuan Chang ◽  
Ji-Pu Wu
Keyword(s):  
Electron Microscopy ◽  
Epitaxial Lateral Overgrowth ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
Air Voids ◽  
X Ray ◽  
Lateral Overgrowth ◽  
Transmission Electron ◽  
Gan Film ◽  
Scanning Electron

GaN epitaxial layers with embedded air voids grown on patterned SiO2AlN/sapphire templates were proposed. Using interruption-free epitaxial lateral overgrowth technology, we realized uninterrupted growth and controlled the shape of embedded air voids. These layers showed improved crystal quality using X-ray diffraction and measurement of etching pits density. Compared with conventional undoped-GaN film, the full width at half-maximum of the GaN (0 0 2) and (1 0 2) peaks decreased from 485 arcsec to 376 arcsec and from 600 arcsec to 322 arcsec, respectively. Transmission electron microscopy results showed that the coalesced GaN growth led to bending threading dislocation. We also proposed a growth model based on results of scanning electron microscopy.

Detailed Characterisations of GaAs Films on Si Obtained by Conformal Growth.

1992 ◽  
Vol 280 ◽  
Author(s):  
B. Gerard ◽  
D. Pribat ◽  
R. Bisaro ◽  
E. Costard ◽  
J. Nagle ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Dislocation Density ◽  
The Self ◽  
Epitaxial Lateral Overgrowth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lateral Overgrowth ◽  
State Of Stress ◽  
Low Dislocation Density ◽  
Gaas Films

ABSTRACTConformal growth is a confined epitaxial lateral overgrowth technique capable of yielding low dislocation density GaAs films on Si. This technique makes extensive use of selective epitaxy and crystal growth is confined by a dielectric cap as well as by the self-passivated Si surface itself.In this paper, we have performed a detailed characterisation of the state of stress of the GaAs films in various configurations (after conformal growth and removal of the seed regions, and after the regrowth of an MBE layer) by photoluminescence measurements at 5K and X-ray diffraction experiments. Although the as-grown conformal films are found in the same state of stress than reference MOCVD GaAs epilayers on Si, we report a significant decrease of this stress after MBE regrowth on conformal films.

Synchrotron X-ray Topography Studies of Epitaxial Lateral Overgrowth of GaN on Sapphire

1999 ◽  
Vol 572 ◽  
Author(s):  
Patrick J. Mcnally ◽  
T. Tuomi ◽  
R. Rantamaki ◽  
K. Jacobs ◽  
L. Considine ◽  
...  
Keyword(s):  
Quantum Well ◽  
Sapphire Substrate ◽  
Large Scale ◽  
Epitaxial Lateral Overgrowth ◽  
Large Area ◽  
X Ray ◽  
Lateral Overgrowth ◽  
Transmission Modes ◽  
Multi Quantum Well

ABSTRACTSynchrotron white beam x-ray topography techniques, in section and large-area transmission modes, have been applied to the evaluation of ELOG GaN on A12O3. Using the openings in 100 nm thick SiO2 windows, a new GaN growth took place, which resulted in typical overgrowth thicknesses of 6.8 μm. Measurements on the recorded Laue patterns indicate that the misorientation of GaN with respect to the sapphire substrate (excluding a 30° rotation between them) varies considerably along various crystalline directions, reaching a maximum of a ∼0.66° rotation of the (0001) plane about the [01•1] axis. This is ∼3% smaller than the misorientation measured in the non-ELOG reference, which reached a maximum of 0.68°. This misorientation varies measurably as the stripe or window dimensions are changed. The quality of the ELOG epilayers is improved when compared to the non- ELOG samples, though some local deviations from lattice coherence were observed. Long range and large-scale (order of 100 μm long) strain structures were observed in all multi quantum well epilayers.

X-Ray Rocking Curve Determination of Twist and Tilt Angles in GaN Films Grown by an Epitaxial-Lateral-Overgrowth Technique

1999 ◽  
Vol 38 (Part 2, No. 6A/B) ◽  
pp. L611-L613 ◽  
Author(s):  
Kenji Kobayashi ◽  
A. Atsushi Yamaguchi ◽  
Shigeru Kimura ◽  
Haruo Sunakawa ◽  
Akitaka Kimura ◽  
...  
Keyword(s):  
Epitaxial Lateral Overgrowth ◽  
Rocking Curve ◽  
X Ray ◽  
Lateral Overgrowth ◽  
Curve Determination

White Beam Synchrotron X-ray Topography and X-ray Diffraction Measurements of Epitaxial Lateral Overgrowth of GaN

2001 ◽  
Vol 693 ◽  
Author(s):  
W.M. Chen ◽  
P.J. McNally ◽  
K. Jacobs ◽  
T. Tuomi ◽  
A.N. Danilewsky ◽  
...  
Keyword(s):  
Fill Factor ◽  
Epitaxial Lateral Overgrowth ◽  
X Ray Diffraction ◽  
Reflection Mode ◽  
Rocking Curve ◽  
X Ray ◽  
Lateral Overgrowth ◽  
White Beam ◽  
Curve Method ◽  
Opening Width

AbstractThe Epitaxial Lateral Overgrowth (ELO) of GaN on Al2O3 using a SiO2 mask with different fill factors (ratio of stripe opening width to stripe period) is examined with White Beam Synchrotron X-ray Topography (WBSXT) and X-ray rocking curve analysis. The sapphire substrate was identified with a dislocation density of the order of ~106cm-2. WBSXT in both transmission and back reflection mode is used to image the ELO GaN and confirms that crystal planes in the lateral overgrown part (wing) are tilted, and that the wing tilt increases as the fill factor increases. X-ray rocking curve and WBSXT measurements confirm the same wing tilt tendency as the fill factor changes. The WBSXT method provides a measure of the maximum wing tilt, while the X-ray rocking curve method gives the average wing tilt. The average wing tilt reaches about 1602 arcsec at a fill factor of 0.625, but the maximum wing tilts can reach values as large as 2372 arcsec when the fill factor is only 0.571. This study shows that WBSXT is an effective method in dislocation and wing tilt determination for the GaN on Al2O3 ELO epilayer system or indeed for similar systems. The tilted wings induce a slightly lower compressive stress in the coalesced region of the GaN epilayer.

The annealed (0001) α-alumina surface and its influence on thin-film growth

1995 ◽  
Vol 53 ◽  
pp. 336-337
Author(s):  
Michael W. Bench ◽  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Surface Energy ◽  
Film Growth ◽  
Thin Film Growth ◽  
Energy Calculations ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Low Energy Electron ◽  
Surface Nature

The growth of semiconductors, superconductors, metals, and other insulators has been investigated using alumina substrates in a variety of orientations. The surface state of the alumina (for example surface reconstruction and step nature) can be expected to affect the growth nature and quality of the epilayers. As such, the surface nature has been studied using a number of techniques including low energy electron diffraction (LEED), reflection electron microscopy (REM), transmission electron microscopy (TEM), molecular dynamics computer simulations, and also by theoretical surface energy calculations. In the (0001) orientation, the bulk alumina lattice can be thought of as a layered structure with A1-A1-O stacking. This gives three possible terminations of the bulk alumina lattice, with theoretical surface energy calculations suggesting that termination should occur between the Al layers. Thus, the lattice often has been described as being made up of layers of (Al-O-Al) unit stacking sequences. There is a 180° rotation in the surface symmetry of successive layers and a total of six layers are required to form the alumina unit cell.

Trenched epitaxial lateral overgrowth of fast coalesced a-plane GaN with low dislocation density

2006 ◽  
Vol 89 (25) ◽  
pp. 251109 ◽  
Author(s):  
Te-Chung Wang ◽  
Tien-Chang Lu ◽  
Tsung-Shine Ko ◽  
Hao-Chung Kuo ◽  
Min Yu ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Epitaxial Lateral Overgrowth ◽  
Lateral Overgrowth ◽  
Low Dislocation Density

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.

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