scholarly journals Strain relaxation in GaN layers grown on porous GaN sublayers

1999 ◽  
Vol 4 (1) ◽  
Author(s):  
M. Mynbaeva ◽  
A. Titkov ◽  
A. Kryzhanovski ◽  
I. Kotousova ◽  
A.S. Zubrilov ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Strain Relaxation ◽  
Vapour Phase ◽  
Crystalline Quality ◽  
Epitaxial Layers ◽  
High Quality ◽  
High Crystalline Quality ◽  
Vapour Phase Epitaxy ◽  
X Ray ◽  
Good Surface

We have studied epitaxial GaN layers grown by hydride vapour phase epitaxy (HVPE) on porous GaN sublayers formed on SiC substrates. It was shown that these layers can be grown with good surface morphology and high crystalline quality. X-ray, Raman and photoluminescent (PL) measurements showed that the stress in the layers grown on porous GaN was reduced to 0.1-0.2 GPa, while the stress in the layers grown directly on 6H-SiC substrates remains at its usual level of about 1 GPa. Thus, we have shown that growth on porous GaN sublayer is a promising method for fabrication of high quality epitaxial layers of GaN with low strain values.

scholarly journals MOVPE growth optimization of high quality InGaN films.

1997 ◽  
Vol 2 ◽  
Author(s):  
W. Van der Stricht ◽  
I. Moerman ◽  
P. Demeester ◽  
L. Considine ◽  
E. J. Thrush ◽  
...  
Keyword(s):  
Rotating Disk ◽  
Vapour Phase ◽  
Band Edge Emission ◽  
Edge Emission ◽  
High Quality ◽  
Vapour Phase Epitaxy ◽  
Rocking Curve ◽  
X Ray ◽  
Growth Optimization ◽  
Sapphire Substrates

In this paper growth of high quality InGaN films on (0001) sapphire substrates by atmospheric pressure organometallic vapour phase epitaxy in a vertical rotating disk reactor is investigated. The InGaN layers grown above 800 °C are transparent and show no In-droplets on the surface. The In-content varies between 56 and 9 % for growth temperatures between 700 and 850 °C. The DC X-ray rocking curve of InGaN typically shows a FWHM between 8 and 15 arcmin. Room temperature PL shows an intense band edge emission with a FWHM between 100 and 200 meV for an In-content of 9 and 56 %. The initial efforts on QW growth are discussed.

A Tem study of GaN Grown by ELO on (0001) 6H-SiC

1999 ◽  
Vol 595 ◽  
Author(s):  
P. Ruterana ◽  
B. Beaumont ◽  
P. Gibart ◽  
Y. Melnik
Keyword(s):  
Basal Plane ◽  
Lattice Mismatch ◽  
Early Stage ◽  
Vapour Phase ◽  
Epitaxial Layers ◽  
Prismatic Plane ◽  
Vapour Phase Epitaxy ◽  
Hexagonal Shape ◽  
To Come

AbstractThe misfit between GaN and 6H-SiC is 3.5% instead of 16% with sapphire, the epitaxial layers have similar densities of defects on both substrates. Moreover, the lattice mismatch between AlN and 6H-SiC is only 1%. Therefore, epitaxial layer overgrowth (ELO) of GaN on AlN/6H-SiC could be a route to further improve the quality of epitaxial layers. AlN has been grown by Halide Vapour Phase Epitaxy (HVPE) on (0001) 6H-SiC, thereafter a dielectric SiO2 mask was deposited and circular openings were made by standard photolithography and reactive ion etching. We have examined GaN layers at an early stage of coalescence in order to identify which dislocations bend and try to understand why. The analysed islands have always the same hexagonal shape, limited by {0110} facets. The a type dislocations are found to fold many times from basal to the prismatic plane, whereas when a+c dislocations bend to the basal plane, they were not seen to come back to a prismatic one.

Electronic structure of short-period ZnSe/ZnTe superlattices grown by MOVPE at 300ºC

1993 ◽  
Vol 308 ◽  
Author(s):  
N. Briot ◽  
T. Cloitre ◽  
O. Briot ◽  
P. Boring ◽  
B.E. Ponga ◽  
...  
Keyword(s):  
Growth Temperature ◽  
Lattice Mismatch ◽  
Stokes Shift ◽  
Vapour Phase ◽  
Potential Candidate ◽  
High Quality ◽  
Vapour Phase Epitaxy ◽  
Light Emitting Devices ◽  
Short Period ◽  
Movpe Growth

ABSTRACTThe ZnSe-ZnTe combination is a potential candidate for the realisation of visible light-emitting devices. The lattice mismatch between bulk ZnSe and bulk ZnTe is important (∼ 8%). Therefore, their hetero-structures are strained and high quality superlattices will only be grown if having small periods. This prescription can be fulfilled in the case of metal organic vapour phase epitaxy (MOVPE) growth by combining triethylamine dimethyl zinc adduct with di-isopropyl telluride as precursors for the growth of the ZnTe layers. The growth of high quality ZnTe can then be performed at a temperature of 300ºC , close to the best MOVPE-growth temperature for ZnSe (280ºC). Lowering the growth temperature of ZnTe to this value, we could thus obtain sharp interfaces. This work reports on ZnSe-ZnTe superlattices grown on ZnSe and ZnTe buffers deposited on GaAs substrates. We demonstrate that the stokes-shift between the reflectance and photoluminescence features ( ∼ 40 meV ) measured when the thickness of ZnSe layers does not exceed 20 Å, drastically increases for layer thicknesses beyond this critical value. This, we interpret in terms of the onset of plastic relaxation which favours tellurium diffusion in the ZnSe slices. Then photoluminescence spectra broaden ( contributions of trapped-excitons dominate), and observation of free excitons in reflectance become impossible. We have studied in detail the optical properties of the superlattices and compared our findings with the predictions of a multiband envelope function calculation. We show that both zone centre excitons as well as excitons associated with the miniband dispersions (saddle-point excitons) are observed in these superlattices.

Stress Relaxation in Uniquely Oriented SiGe/Si Epitaxial Layers

1999 ◽  
Vol 594 ◽  
Author(s):  
M. E. Ware ◽  
R. J. Nemanich
Keyword(s):  
Stress Relaxation ◽  
Surface Morphology ◽  
Strain Relaxation ◽  
Epitaxial Layers ◽  
Misfit Dislocations ◽  
Strained Layers ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Deposited Films

AbstractThis study explores stress relaxation of epitaxial SiGe layers grown on Si substrates with unique orientations. The crystallographic orientations of the Si substrates used were off-axis from the (001) plane towards the (111) plane by angles, θ = 0, 10, and 22 degrees. We have grown 100nm thick Si(1−x) Ge(x) epitaxial layers with x=0.3 on the Si substrates to examine the relaxation process. The as-deposited films are metastable to the formation of strain relaxing misfit dislocations, and thermal annealing is used to obtain highly relaxed films for comparison. Raman spectroscopy has been used to measure the strain relaxation, and atomic force microscopy has been used to explore the development of surface morphology. The Raman scattering indicated that the strain in the as-deposited films is dependent on the substrate orientation with strained layers grown on Si with 0 and 22 degree orientations while highly relaxed films were grown on the 10 degree substrate. The surface morphology also differed for the substrate orientations. The 10 degree surface is relatively smooth with hut shaped structures oriented at predicted angles relative to the step edges.

Silane controlled three dimensional GaN growth and recovery stages on a cone-shape nanoscale patterned sapphire substrate by MOCVD

CrystEngComm ◽  
2015 ◽  
Vol 17 (24) ◽  
pp. 4469-4474 ◽  
Author(s):  
J. Z. Li ◽  
Z. Z. Chen ◽  
Q. Q. Jiao ◽  
Y. L. Feng ◽  
S. Jiang ◽  
...  
Keyword(s):  
Sapphire Substrate ◽  
Strain Relaxation ◽  
Three Dimensional ◽  
Crystalline Quality ◽  
High Crystalline Quality ◽  
Patterned Sapphire Substrate ◽  
Specular Surface

The silane-controlled 3D growth led to a high crystalline quality, much strain relaxation and a specular surface for the GaN epilayers on NPSS.

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.

scholarly journals Aluminium incorporation in polar, semi- and non-polar AlGaN layers: a comparative study of x-ray diffraction and optical properties

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Duc V. Dinh ◽  
Nan Hu ◽  
Yoshio Honda ◽  
Hiroshi Amano ◽  
Markus Pristovsek
Keyword(s):  
Room Temperature ◽  
Optical Emission ◽  
Vapour Phase ◽  
Optical Data ◽  
Bandgap Energy ◽  
X Ray Diffraction ◽  
Vapour Phase Epitaxy ◽  
X Ray ◽  
Metal Organic ◽  
Organic Vapour

Abstract Growth of AlxGa1−xN layers (0 ≤ x ≤ 1) simultaneously on polar (0001), semipolar ($$10\bar{{\rm{1}}}$$ 10 1 ¯ 3) and ($$11\bar{{\rm{2}}}2$$ 11 2 ¯ 2 ), as well as nonpolar ($$10\bar{{\rm{1}}}0$$ 10 1 ¯ 0 ) and ($$11\bar{{\rm{2}}}0$$ 11 2 ¯ 0 ) AlN templates, which were grown on planar sapphire substrates, has been investigated by metal-organic vapour phase epitaxy. By taking into account anisotropic in-plane strain of semi- and non-polar layers, their aluminium incorporation has been determined by x-ray diffraction analysis. Optical emission energy of the layers was obtained from room-temperature photoluminescence spectra, and their effective bandgap energy was estimated from room-temperature pseudo-dielectric functions. Both x-ray diffraction and optical data consistently show that aluminium incorporation is comparable on the polar, semi- and non-polar planes.

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