Initial Growth Mode of GaN Film on Stepped Sapphire

2007 ◽  
Vol 124-126 ◽  
pp. 61-64
Author(s):  
Min Su Yi ◽  
Tae Sik Cho ◽  
Hyun Hwi Lee
Keyword(s):  
Sapphire Substrate ◽  
Early Stage ◽  
Growth Mode ◽  
Atomic Step ◽  
Layer By Layer ◽  
Initial Growth ◽  
Nucleation Layer ◽  
X Ray ◽  
Metal Organic ◽  
Gan Film

The initial GaN growth mode on stepped sapphires by plasma enhanced metal organic molecular beam epitaxy (PEMOMBE) has been analyzed using in-situ, real time synchrotron x-ray diffraction and x-ray absorption. The sapphire substrate annealed at high temperature had flat terraces and regular atomic steps. The crystal quality and the vicinal angle of sapphire substrate had an effect on the width of terraces and the step arrangement. The initial growth mode of the GaN film on the regular atomic step (AS) surface was the layer-by-layer mode and changed to the 3D growth mode within 2 bilayer thickness. In the meanwhile, the growth mode of the GaN film grown on the sapphire with random roughness (RR) surface made the flat surface in the early stage and changed the 3D growth mode. As increasing the film thickness, the nucleation layer grows strain-free hexagonal GaN on stepped sapphires

scholarly journals Initial Growth and Crystallization Onset of Plasma Enhanced-Atomic Layer Deposited ZnO

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 291
Author(s):  
Alberto Perrotta ◽  
Julian Pilz ◽  
Roland Resel ◽  
Oliver Werzer ◽  
Anna Maria Coclite
Keyword(s):  
Atomic Layer ◽  
Layer Growth ◽  
Growth Mode ◽  
Ex Situ ◽  
Native Oxide ◽  
Layer By Layer ◽  
Initial Growth ◽  
Island Growth ◽  
X Ray ◽  
Crystallization Onset

Direct plasma enhanced-atomic layer deposition (PE-ALD) is adopted for the growth of ZnO on c-Si with native oxide at room temperature. The initial stages of growth both in terms of thickness evolution and crystallization onset are followed ex-situ by a combination of spectroscopic ellipsometry and X-ray based techniques (diffraction, reflectivity, and fluorescence). Differently from the growth mode usually reported for thermal ALD ZnO (i.e., substrate-inhibited island growth), the effect of plasma surface activation resulted in a substrate-enhanced island growth. A transient region of accelerated island formation was found within the first 2 nm of deposition, resulting in the growth of amorphous ZnO as witnessed with grazing incidence X-ray diffraction. After the islands coalesced and a continuous layer formed, the first crystallites were found to grow, starting the layer-by-layer growth mode. High-temperature ALD ZnO layers were also investigated in terms of crystallization onset, showing that layers are amorphous up to a thickness of 3 nm, irrespective of the deposition temperature and growth orientation.

Growth of CaFeOX/LaFeO3 Superlattice on SrTiO3(100) Substrates

2011 ◽  
Vol 1292 ◽  
Author(s):  
Nobuyuki Iwata ◽  
Mark Huijben ◽  
Guus Rijnders ◽  
Hiroshi Yamamoto ◽  
Dave H. A. Blank
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Layer Growth ◽  
Laser Deposition ◽  
Growth Mode ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Reciprocal Space Mapping ◽  
X Ray

ABSTRACTThe CaFeOX(CFO) and LaFeO3(LFO) thin films as well as superlattices were fabricated on SrTiO3(100) substrates by pulsed laser deposition (PLD) method. The tetragonal LFO film grew with layer-by-layer growth mode until approximately 40 layers. In the case of CFO, initial three layers showed layer-by-layer growth, and afterward the growth mode was transferred to two layers-by-two layers (TLTL) growth mode. The RHEED oscillation was observed until the end of the growth, approximately 50nm. Orthorhombic twin CaFeO2.5 (CFO2.5) structure was obtained. However, it is expected that the initial three CFO layers are CaFeO3 (CFO3) with the valence of Fe4+. The CFO and LFO superlattice showed a step-terraces surface, and the superlattice satellite peaks in a 2θ-θ and reciprocal space mapping (RSM) x-ray diffraction (XRD) measurements, indicating that the clear interfaces were fabricated.

scholarly journals Growth mode and surface morphology of a GaN film deposited along the N-face polar direction on c-plane sapphire substrate

2000 ◽  
Vol 88 (2) ◽  
pp. 1158-1165 ◽  
Author(s):  
M. Sumiya ◽  
K. Yoshimura ◽  
T. Ito ◽  
K. Ohtsuka ◽  
S. Fuke ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Sapphire Substrate ◽  
Growth Mode ◽  
Polar Direction ◽  
Gan Film

Effect of Graded AlxGa1-xN Interlayer Buffer on the Strain of GaN Grown on Si (111) Using MOCVD Method

2008 ◽  
Vol 1068 ◽  
Author(s):  
KungLiang Lin ◽  
Edward-Yi Chang ◽  
Tingkai Li ◽  
Wei-Ching Huang ◽  
Yu-Lin Hsiao ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Buffer Layers ◽  
Organic Chemical ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
X Ray ◽  
Metal Organic ◽  
Proper Design ◽  
Organic Chemical Vapor Deposition ◽  
Gan Film

ABSTRACTGaN film grown on Si substrate with AlN/AlxGa1−xN buffer is studied by low pressure metal organic chemical vapor deposition (MOCVD) method. The AlxGa1−xN film with Al composition varying from 0∼ 0.66 was used. The correlation of the Al composition in the AlxGa1−xN film with the stress of the GaN film grown was studied using high resolution X-ray diffraction including symmetrical and asymmetrical ω/2θscans and reciprocal space maps. It is found that with proper design of the Al composition in the AlxGa1−xN buffer layer, crack-free GaN films can be successfully grown on Si (111) substrates using AlN and AlxGa1−xN buffer layers.

The Effect of a GaN Nucleation Layer on GaN Film Properties Grown by Metalorganic Chemical Vapor Deposition

1995 ◽  
Vol 395 ◽  
Author(s):  
W. Van Der Stricht ◽  
I. Moerman ◽  
P. Demeester ◽  
J.A Crawley ◽  
E.J. Thrush ◽  
...  
Keyword(s):  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
Rotating Disk ◽  
X Ray Diffraction ◽  
Film Properties ◽  
Double Crystal ◽  
Nucleation Layer ◽  
X Ray ◽  
Sapphire Substrates ◽  
Gan Film

ABSTRACTIn this paper GaN films are examined, which are grown on basal plane (0001) sapphire substrates. Growth is performed in a novel type of vertical rotating disk reactor. Results on the effect of a GaN nucleation layer on the properties of the overgrown GaN epilayer are presented. Characterisation includes surface morphology studies, DC X-ray diffraction and optical characterisation. Best film quality so far has a double crystal X-ray half width of 85 arcsec at approximately 1 μm thickness.

HVPE Growth of GaN Layers on Cleaved β-Ga2O3 Substrates

2016 ◽  
Vol 674 ◽  
pp. 302-307 ◽  
Author(s):  
V.I. Nikolaev ◽  
A.I. Pechnikov ◽  
S.I. Stepanov ◽  
V.M. Krymov ◽  
V.N. Maslov ◽  
...  
Keyword(s):  
Deposition Time ◽  
Substrate Surface ◽  
Vapour Phase ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
Nucleation Layer ◽  
Vapour Phase Epitaxy ◽  
X Ray ◽  
Gan Film

GaN epitaxial layers were successfully grown by hydride vapour phase epitaxy (HVPE) on β-Ga2O3 substrates produced by cleaving. The initial stages of GaN epitaxial growth on β-Ga2O3 were studied by scanning electron microscopy (SEM) and x-ray diffraction analysis (XRD). The nucleation and the transition from the nucleation layer to a continuous GaN film were studied. It was found that the growth starts with formation of small crystallites on the substrate surface. As the growth continues, crystallites transform into pyramidal islands which increase in size and merge together. It was found that the structural quality of the GaN layers rapidly improves with increasing thickness. The full width at half maximum of x-ray ω rocking curves for (0002) peak decreased from 1370 to 540 arcsec as the deposition time was increased from 30 to 120 sec. This corresponds to the variation of the nominal layer thickness from 250 nm to 1000 nm.

X-Ray Photoelectron and Auger Electron Forward-Scattering Studies of the Epitaxial Growth of Fe on Ag(100).

1991 ◽  
Vol 229 ◽  
Author(s):  
William F. Egelhoff
Keyword(s):  
Electron Diffraction ◽  
Auger Electron ◽  
High Energy ◽  
Layer Growth ◽  
Forward Scattering ◽  
Energy Electron ◽  
Atomic Step ◽  
Layer By Layer ◽  
X Ray ◽  
Place Exchange

AbstractA controversy has arisen in the past year over whether or not the growth of Fe on Ag(100) at room temperature occurs by a layer-by-layer mechanism. The present work attempts to address this controversy with an investigation of the issues, primarily by x-ray photoelectron (XPS) and Auger electron forward scattering, but with important supporting data from low-energy electron diffraction (LEED), and reflection high-energy electron diffraction (RHEED) oscillations. The results of this work suggest that the origin of the controversy lies in different substrate preparation techniques which produce different atomic step densities on the Ag(100) surface. The step sites are implicated as being the initiators of major departures from a layer-by-layer growth mode whenever most of the deposited Fe atoms have sufficient mobility to reach these steps. However, even when the Fe atoms cannot reach these steps it appears that atomic place-exchange occurs with ≥25% of the top-layer Ag atoms. Atomic place-exchange mechanisms, which could account for this intermixing, have been observed in recent molecular-dynamics simulations of epitakial growth. Thus it seems probable that under the conditions that appear to produce layer-by-layer growth, the growth begins as layer-by-layer growth of an FeAg alloy, and only becomes layer-by-layer in pure Fe as the segregating Ag atoms gradually get left behind in the growing Fe film.

scholarly journals Growth mode study of MgCl2 on Au foil and Si (111) 7x7, under Ultra High Vacuum by XPS

2011 ◽  
Vol 1 (1) ◽  
pp. 13-16
Author(s):  
S. Karakalos
Keyword(s):  
Surface Roughness ◽  
Photoelectron Spectroscopy ◽  
Magnesium Chloride ◽  
High Vacuum ◽  
Layer Growth ◽  
Ultra High Vacuum ◽  
Growth Mode ◽  
Layer By Layer ◽  
X Ray ◽  
Reconstructed Surface

The growth mode of MgCl2 on Au foil and Si (111) 7x7 reconstructed surface under UHV conditions, was investigated by X-ray Photoelectron Spectroscopy (XPS). Magnesium chloride grows with the Frank-van der Merve, (FM) growth mode on the Au foil. On Si surface there is evidence for the layer by layer growth of MgCl2 but leaving uncovered silicon areas at the first steps of deposition due to the Si (111)7x7 surface roughness.

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