scholarly journals A TEM study of GaN grown by ELO on (0001) 6H-SiC

2000 ◽  
Vol 5 (S1) ◽  
pp. 76-82
Author(s):  
P. Ruterana ◽  
B. Beaumont ◽  
P. Gibart ◽  
Y. Melnik
Keyword(s):  
Lattice Mismatch ◽  
Early Stage ◽  
Vapour Phase ◽  
Epitaxial Layers ◽  
Prismatic Plane ◽  
Vapour Phase Epitaxy ◽  
Hexagonal Shape ◽  
To Come ◽  
Image Position

The 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 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.

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.

Residual and thermal strain of ZnS epitaxial layers grown on (100)-GaAs by vapour phase epitaxy

1995 ◽  
Vol 28 (4A) ◽  
pp. A125-A128 ◽  
Author(s):  
C Giannini ◽  
L Tapfer ◽  
T Peluso ◽  
N Lovergine ◽  
L Vasanelli
Keyword(s):  
Thermal Strain ◽  
Vapour Phase ◽  
Epitaxial Layers ◽  
Vapour Phase Epitaxy

Optically-Pumped Lasing of Doped ZnSe Epitaxial Layers Grown by Metal-Organic Vapour-Phase Epitaxy

1997 ◽  
Vol 159 (2) ◽  
pp. 543-557 ◽  
Author(s):  
G. P. Yablonskii ◽  
A. L. Gurskii ◽  
E. V. Lutsenko ◽  
I. P. Marko ◽  
H. Hamadeh ◽  
...  
Keyword(s):  
Vapour Phase ◽  
Epitaxial Layers ◽  
Optically Pumped ◽  
Vapour Phase Epitaxy ◽  
Metal Organic ◽  
Organic Vapour

The Composition Pulling Effect in InGaN Growth on the GaN and AlGaN Epitaxial Layers Grown by MOVPE

1996 ◽  
Vol 449 ◽  
Author(s):  
Yasutoshi Kawaguchi ◽  
Masaya Shimizu ◽  
Kazumasa Hiramatsu ◽  
Nobuhiko Sawaki
Keyword(s):  
Mole Fraction ◽  
Vapor Phase ◽  
Growth Stage ◽  
Lattice Mismatch ◽  
Metalorganic Vapor Phase Epitaxy ◽  
Crystalline Quality ◽  
Epitaxial Layers ◽  
Initial Growth ◽  
Initial Growth Stage

ABSTRACTInGaN has been grown on GaN and AlGaN epitaxial layers by metalorganic vapor phase epitaxy (MOVPE) and ‘the composition pulling effect’ at the initial growth stage of InGaN has been studied in relation to the lattice mismatch between InGaN and the bottom epitaxial layers. Crystalline quality of InGaN is good near the interface of InGaN/GaN and the composition of InGaN is close to that of GaN. With increasing growth thickness, the crystalline quality becomes worse and the indium mole fraction is increased. The composition pulling effect becomes stronger with increasing lattice mismatch.

Submicron Highly Doped Silicon Epitaxial Layers Grown by Lpvpe

1986 ◽  
Vol 71 ◽  
Author(s):  
L. Vescan ◽  
H. Beneking ◽  
O. Meyer
Keyword(s):  
Epitaxial Growth ◽  
Schottky Barrier ◽  
Boron Doping ◽  
Low Pressure ◽  
Vapour Phase ◽  
Doping Profile ◽  
Epitaxial Layers ◽  
Vapour Phase Epitaxy ◽  
Doped Silicon

AbstractBy low pressure vapour phase epitaxy (LPVPE) epitaxial growth down to 760ºC has been achieved in the SiC12H2/H2 system, as revealed by RBS and channeling measurements ( min ∼4.0%). High and relative homogeneous doping was obtained with boron resp. phosphorus in the range 1x1018 -5x1019 cm-3 for T: 800º - 900ºC. Sharp transitions in the boron doping profile to the substrate, of the order of 15mn, result only for temperatures much lower than 850ºC. Schottky barrier enhanced diodes with promising performances were formed with Ti evaporated on p+n layers grown selectively on n+ substrates.

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.

Ion Scattering Studies of Defects In Gan Thin Films on C-Oriented Sapphire

1998 ◽  
Vol 512 ◽  
Author(s):  
B. Holländer ◽  
S. Mantl ◽  
M. Mayer ◽  
C. Kirchner ◽  
A. Pelzmann ◽  
...  
Keyword(s):  
Lattice Mismatch ◽  
Vapour Phase ◽  
Structural Defects ◽  
Ion Scattering ◽  
Vapour Phase Epitaxy ◽  
Screw Dislocations ◽  
Ion Channeling ◽  
Thermal Expansion Coefficients ◽  
Organic Vapour ◽  
Edge Dislocations

ABSTRACTEpitaxial GaN films grown by metal organic vapour phase epitaxy (MOVPE) or gas source molecular beam epitaxy (GSMBE) have opened up new applications in short wavelength photonic devices as well as high-power and high-temperature devices. The large lattice mismatch of 14% between GaN and sapphire, which is frequently used as the substrate, and the different thermal expansion coefficients generally lead to high densities of structural defects. We investigate the defect structure of MOVPE- and GSMBE-grown GaN layers on sapphire by Rutherford backscattering and ion channeling measurements. Channeling along the c-axis revealed χmin-values as low as 1.2% even in samples with dislocation densities in the order of 109 cm−2. Channeling measurements along different crystal planes were performed in order to improve the sensitivity to dechanneling by crystalline defects. Angular yield scans around the c-axis indicate clearly the hexagonal symmetry of the GaN lattice. Dechanneling results were combined with transmission electron microscopy investigations (TEM). The results suggest that the dechanneling-cross-section of edge dislocations is about 4 times larger than the dechannelingcross-section of screw dislocations. screw dislocations.

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