Comparative Analysis of Strain and Stress in MBE and MOCVD grown GaN thin films on sapphire

1997 ◽  
Vol 482 ◽  
Author(s):  
Joachim Krüger ◽  
Sudhir G.S. ◽  
Dorina Corlatan ◽  
Yonah Cho ◽  
Viihwan Kim ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Hydrostatic Stress ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Mocvd Growth ◽  
Stress Components ◽  
Metal Organic ◽  
The Difference ◽  
Organic Chemical Vapor Deposition ◽  
Physical Principles

AbstractIn this study, the causes of biaxial and hydrostatic stress components in epitaxially grown thin GaN films on sapphire are analyzed. It is observed that growth by Molecular Beam Epitaxy (MBE) and by Metal Organic Chemical Vapor Deposition (MOCVD) are governed by very similar physical principles. Differences in the absolute stress values are mainly due to the difference in growth temperature. It is argued that in the case of MOCVD growth the onset of plasticity for higher growth temperatures is responsible for a larger stress relaxation in the buffer layer. It is further found that either process can result in highly off-stoichiometric GaN layers, as manifested by the large variations in the a and c lattice parameters caused by intrinsic point defects.

MOCVD Growth of Ga(Al)N/InGaN/Ga(Al)N-Heterostructures: Influence of the Buffer Layer Al-Concentration and Growth Duration on the In-Incorporation in InGaN

2001 ◽  
Vol 680 ◽  
Author(s):  
Marco Schowalter ◽  
Brigitte Neubauer ◽  
Andreas Rosenauer ◽  
Dagmar Gerthsen ◽  
Oliver Schön ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Organic Chemical ◽  
Growth Duration ◽  
Mocvd Growth ◽  
Transmission Electron ◽  
Metal Organic ◽  
Composition Fluctuations ◽  
Organic Chemical Vapor Deposition

ABSTRACTTransmission electron microscopy (TEM) has been applied to analyze the thickness and the In-concentration of InGaN layers in GaN/InGaN/GaN- and AlGaN/InGaN/AlGaN-quantum well (QW) structures. Two series of samples were grown by metal organic chemical vapor deposition varying either only the growth duration for the InGaN QW or by changing the Al- concentration in the buffer layers at unaltered InGaN growth conditions. A rising average In- concentration from 6.5 to 15.4 % and a decreasing growth rate are observed with increasing growth duration. The increase of the Al-concentration in the buffer layers from 0 to 36 % strongly affects the In-incorporation during the InGaN growth, which decreases from 17.5 to 2.5 %. All samples are characterized by an inhomogeneous In-distribution containing In-rich agglomerates with a size of only a few nanometers and less pronounced composition fluctuations on a scale of 100 nm.

Improvement in the FF over 0.700 by Controlling the Interface Quality

2009 ◽  
Vol 1165 ◽  
Author(s):  
Katsumi Kushiya ◽  
Y. Tanaka ◽  
H. Hakuma ◽  
S. Kijima ◽  
T. Aramoto ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Deposition Process ◽  
Organic Chemical ◽  
Surface Layers ◽  
Shunt Resistance ◽  
Interface Quality ◽  
Metal Organic ◽  
The Difference ◽  
Organic Chemical Vapor Deposition ◽  
Mocvd Technique

AbstractIn this study, the pn hetero-interface between Zn(O,S,OH)x buffer and Cu(InGa)(SSe)2 (CIGSS) surface layers is discussed in order to achieve the fill factor (FF) over 0.73 and the circuit efficiency of 16 % on aperture area of over 800 cm2. Two resistances, i.e. shunt resistance (Rsh) and series resistance (Rs), in the circuits are employed as a yardstick to evaluate the interface quality. Since there are no realistic yardsticks on the Rs, the difference between Voc and optimum-power voltage (Vop) (i.e. Voc-Vop [V/cell]) is applied as a simple tool to evaluate the Rs. It is emphasized that it is important to reduce the Rs mainly correlated to the buffer deposition process and, as a result, the interface quality. We consider the Rs is dependent on the remaining Zn(OH)2 concentration in the Zn(O,S,OH)x buffer deposited by a chemical-bath deposition (CBD) technique. As an approach to make the Rs minimize and the Rsh maximize simultaneously, adjusting the thickness of a CBD-Zn(O,S,OH)x buffer layer and a non-doped ZnO layer deposited by a metal-organic chemical vapor deposition (MOCVD) technique has been effective to reduce the remaining Zn(OH)2 concentration. Determining the optimized deposition procedure to achieve the FF over 0.700 consistently, the circuit efficiency of 15.3 % with aperture area of 856 cm2 and the FF of 0.717 has been achieved.

Dependence on MOCVD Growth Temperature of The Photoluminescence Properties of ZnSe, ZnTe, and ZnSe(1-x)Te(x) Alloys and ZnSe/ZnTe Superlattices

1992 ◽  
Vol 263 ◽  
Author(s):  
B.E. Ponga ◽  
J. Calas ◽  
M. Averous ◽  
T. Cloitre ◽  
O. Briot ◽  
...  
Keyword(s):  
Low Temperature ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Physical Situation ◽  
Temperature Growth ◽  
Mocvd Growth ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition ◽  
Ethyl Amine

ABSTRACTIt has been recently shown that high quality ZnSe and ZnTc filns can be grown on GaAs using low temperature growth techniques such as Metal-Organic Chemical Vapor Deposition ( MOCVD). All samples: ZnSe, ZnTe, ZnSc(l−x)Tc(x) epilayers and ZnSe/ZnTc superlattices were grown using a novel zinc precursor, the Tri-Ethyl-Amine Di-Methyl-Zinc, while we used the classical precursors H2Se and Di-Isopropyl-Tellurium for selenium and tellurium. Investigation of the photoluminescence (PL) properties of ZnSc and ZnTe single layers enabled us to optimize the growth conditions of these compounds. The crystal growth conditions for mixed alloys and superlattices were determined by direct comparison to the aspect of low-temperature PL features. Strong PL spectra were obtained from these materials, suggesting us that tellurium has the ability to behave like an iso-clectronic center. At low concentration of tellurium in ZnSe, an interesting physical situation is observed, which we have interpreted in terms of extrinsic exciton “self-trapping” mechanism.

The Role of Nitrogen-Induced Localization and Defects in InGaAsN (? 2% N): Comparison of InGaAsN Grown by Molecular Beam Epitaxy and Metal-Organic Chemical Vapor Deposition

2001 ◽  
Vol 692 ◽  
Author(s):  
Steven R Kurtz ◽  
A. A. Allermana ◽  
J. F. Klem ◽  
R. M. Sieg ◽  
C. H. Seager ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Molecular Beam Epitaxy ◽  
Vapor Deposition ◽  
Molecular Beam ◽  
Minority Carrier ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Carrier Diffusion ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

AbstractNitrogen vibrational mode spectra, Hall mobilities, and minority carrier diffusion lengths are examined for InGaAsN (≈ 1.1 eV bandgap) grown by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD). Independent of growth technique, annealing promotes the formation of In-N bonding, and lateral carrier transport is limited by large scale (Ęmean free path ) material inhomogeneities. Comparing solar cell quantum efficiencies for devices grown by MBE and MOCVD, we find significant electron diffusion in the MBE material (reversed from the hole diffusion occurring in MOCVD material), and minority carrier diffusion in InGaAsN cannot be explained by a “universal”, nitrogen-related defect.

Thermodynamic Constraints for the In Situ MOCVD Growth of Superconducting Tl-Ba-Ca-Cu-O Thin Films

1993 ◽  
Vol 335 ◽  
Author(s):  
William L. Holstein
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Mocvd Growth ◽  
Metal Organic ◽  
Deposition Processes ◽  
Organic Chemical Vapor Deposition

AbstractIn spite of several attempts, superconducting Tl-Ba-Ca-Cu-O thin films have not been successfully prepared in situ by metal organic chemical vapor deposition (MOCVD). Preparation of a phase by MOCVD requires that it be thermodynamically stable with respect to its decomposition into volatile species and other condensed phases. For MOCVD growth of Tl-Ba- Ca-Cu-O compounds in the presence of oxygen from reagents containing only C-H or C-H-O ligands, Tl2O(g) and TIOH(g) exhibit appreciable volatility. If reagents with ligands containing fluorine are used, the formation of volatile TIF(g) must also be considered. Thermodynamic data for these materials are compiled, and thermodynamic relationships between these gases, H2O(g) and HF(g) are established. The thermodynamic stability of TIOH(g) and TIF(g) makes the in situ growth of Tl-Ba-Ca-Cu-O compounds by MOCVD more difficult than their in situ growth by physical vapor deposition processes, for which Tl2O(g) is the only volatile TI-containing species present.

Persistent Photoconductivity in p-Type GaN Epilayers and n-Type AlGaN/GaN Heterostructures

1996 ◽  
Vol 449 ◽  
Author(s):  
J. Z. Li ◽  
J. Y. Lin ◽  
H. X. Jiang ◽  
M. A. Khan ◽  
Q. Chen ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Persistent Photoconductivity ◽  
Dimensional Electron ◽  
Metal Organic ◽  
Dimensional Electron Gas ◽  
Gan Heterostructure ◽  
P Type ◽  
Organic Chemical Vapor Deposition

ABSTRACTPersistent photoconductivity (PPC) effect has been observed in p-type GaN epilayers grown both by metal-organic chemical vapor deposition (MOCVD) and reactive molecular beam epitaxy (MBE) as well as in a two-dimensional electron gas (2DEG) system formed by an AlGaN/GaN heterostructure grown by MOCVD. Its properties have been investigated at different conditions.

Photo-Assisted Mocvd Growth of High Dielectric (Ba,Sr)TiO3 Thin Films on Ni/TiN/Si Substrate for Dram Application

1999 ◽  
Vol 596 ◽  
Author(s):  
Y. M. Chen ◽  
N. J. Wu ◽  
A. Ignatiew
Keyword(s):  
Thin Films ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Strontium Titanium Oxide ◽  
Mocvd Growth ◽  
Barium Strontium ◽  
Metal Organic ◽  
Current Densities ◽  
High Dielectric ◽  
Organic Chemical Vapor Deposition

AbstractHigh dielectric constant barium strontium titanium oxide (BST) thin films have been deposited on Ni/TiN/Si by photo-assisted metal organic chemical vapor deposition (PhAMOCVD). Planar capacitors based on the Ni/BST/Ni/TiN/Si heterostructure with BST-layer thickness of 50nm exhibited storage densities of about 30 fF/μm2 and leakage current densities of less than 10–7 A/cm2 under bias below 1.8V at room temperature. Nickel as a bottom electrode in this newly designed capacitor structure, can be easily patterned by reactive ion etching, and satisfies the requirement for integration with silicon.

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