MO-CVD GaAs Grown by Direct Deposition on Si

1987 ◽  
Vol 91 ◽  
Author(s):  
S. M. Vernon ◽  
S. J. Pearton ◽  
J. M. Gibson ◽  
R. Caruso ◽  
C. R. Abernathy ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Gaas Layer ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Transmission Electron ◽  
Activation Data ◽  
Threading Dislocation Density ◽  
Donor Activity

ABSTRACTGaAs layers were grown directly on misoriented (2° off (100)→[011]) Si substrates by Metalorganic Chemical Vapor Deposition. The threading dislocation density at the surface of 4 μm thick layers was typically 108cm−2, as determined by both preferential etching and transmission electron microscopy. Rapid thermal annealing (900°C, 10s) improved the crystalline quality of the GaAs near the heterointerface while allowing no detectable Si diffusion into this layer. Two deep electron traps were observed in the undoped GaAs, but were present at a low concentration (∼ 1013 cm−3 ). The (400) x-ray diffraction peak width from the GaAs was significantly reduced with increasing GaAs layer thickness, indicating improved material quality. This is supported by Si implant activation data, which shows higher net donor activity in thicker layers.

Correlation Between Defect Density and Process Variables In Step-Graded, Relaxed Si0.7Ge0.3 Grown on Si by Rtcvd

1993 ◽  
Vol 303 ◽  
Author(s):  
G. Patrick Watson ◽  
Eugene A. Fitzgerald ◽  
Bahram Jalali ◽  
Ya-Hong Xie ◽  
Bonnie Weir ◽  
...  
Keyword(s):  
Defect Density ◽  
Chemical Vapor ◽  
Dark Spot ◽  
Threading Dislocation ◽  
Dark Line ◽  
Si Substrates ◽  
Transmission Electron ◽  
Threading Dislocation Density ◽  
Line Defects ◽  
Threading Defects

ABSTRACTThe effect of the average grading rate and of the number of incremental Ge alloy steps on the threading dislocation density has been studied in 30% Ge relaxed films formed by rapid thermal chemical vapor deposition (RTCVD) on Si substrates. Electron beam induced current (EBIC) images and transmission electron microscopy (TEM) show that threading defects fall in two categories: individual threading dislocations (dark spot defects), and organized clusters of these threads (pile-ups, or dark line defects). The overall surface defect density must include both categories to properly characterize the material. The lowest defect density, 4 × 105cm−2, was found in specimens grown at an average grading rate of 10% Ge per pm thickness.

Defect Reduction in GaAs Grown on Si by Using Saw-Tooth-Patterned Substrates

1992 ◽  
Vol 281 ◽  
Author(s):  
Jane G. Zhu ◽  
M. M. Al-Jassim ◽  
N. H. Karam ◽  
K. M. Jones
Keyword(s):  
Dislocation Density ◽  
Chemical Vapor ◽  
Growth Front ◽  
Organic Chemical ◽  
Threading Dislocation ◽  
Defect Reduction ◽  
Dislocation Configuration ◽  
Si Substrates ◽  
Transmission Electron ◽  
Threading Dislocation Density

ABSTRACTEpitaxial GaAs layers have been grown on saw-tooth-patterned (STP) Si substrates by metal-organic chemical vapor deposition and analyzed by transmission electron microscopy. The utilization of this special interface feature is effective in suppressing the formation of antiphase boundaries and reducing the threading dislocation density. The growth of GaAs has been studied with the epilayer thicknesses ranging from several hundred angstroms to several microns. Very flat growth front on (100) plane above the STP region is observed. The dislocation density decreases very rapidly in the area farther away from the interface. The dislocation configuration at this STP interface is very different from that at the extensively studied two-dimensional planar interface.

Impact of Small Miscuts of (0001) Sapphire on the Growth of AlxGa1-xN/AlN

2005 ◽  
Vol 864 ◽  
Author(s):  
Zheng Gong ◽  
Wenhong Sun ◽  
Jianping Zhang ◽  
Mikhail E. Gaevski ◽  
Hongmei Wang ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
Step Flow ◽  
Atomic Force ◽  
Full Structure ◽  
Threading Dislocation Density ◽  
Flow Morphology ◽  
Surface Morphologies

AbstractIn this paper, using chemical etching, atomic force microscope (AFM) and High- resolution X-ray diffraction (HRXRD), we report a study of the effect of various small miscuts of (0001) sapphire substrate (<1°) and the way to further improve the material quality. A set of AlN epilayers and AlN/AlxGa1-xN Superlattices (SLs) were grown by Migration-enhanced Metalorganic Chemical Vapor Deposition (MEMOCVD) on vicinal (0001) sapphire substrates. The threading dislocation density was found to be very sensitive to the miscut angles. The etch pit density reduced to 7×106 cm-2 for normal-oriented (0°-off) from the starting value of 7×107 cm-2 for 0.5°-off. We found the surface morphologies can be easily controlled by the different substrate miscut angles. The 1-2 Monolayers (MLs) step flow morphology for normal- oriented substrate changed to step bunches of 10 MLs height for 0.5°-off substrate. Correspondingly, AFM Root Mean Square (RMS) increased from 1.52 to 9.15 Å with a 5um×5um scan. This finding may help enhance the quality of full structure UVLED material and eventually improve the lifetime of UVLEDs.

Defect Reduction in Cd1-xZnxTe Epilayers on GaAs Substrates

1994 ◽  
Vol 299 ◽  
Author(s):  
Saket Chadda ◽  
Kevin Malloy ◽  
John Reno
Keyword(s):  
Threading Dislocation ◽  
Full Width ◽  
X Ray Diffraction ◽  
Defect Reduction ◽  
X Ray ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Threading Dislocation Density ◽  
Optimum Period ◽  
Bulk Alloys

AbstractCd0.91Zn0.09Te/CdTe multilayers of various period thicknesses were inserted into Cd0.955Zn0.045Te bulk alloys grown on (001) GaAs. The net strain of the multilayer on the underlying Cd0.955Zn0.045Te was designed to be zero. X-ray diffraction full width at half maximum (FWHM) was used as a means to optimize the period thickness of the multilayer. Transmission electron microscopy of the optimum period thickness samples demonstrated four orders of magnitude decrease in the threading dislocation density. Mechanism of bending by equi-strained multilayers is discussed.

Ge Growth on Nanostructured Silicon Surfaces

2005 ◽  
Vol 862 ◽  
Author(s):  
Ganesh Vanamu ◽  
Abhaya K. Datye ◽  
Saleem H. Zaidi
Keyword(s):  
Electron Microscopy ◽  
Dislocation Density ◽  
Full Width Half Maximum ◽  
Defect Density ◽  
Chemical Vapor ◽  
Silicon Surfaces ◽  
X Ray Diffraction ◽  
Etch Pit ◽  
Transmission Electron

AbstractWe report highest quality Ge epilayers on nanoscale patterned Si structures. 100% Ge films of 10 μm are deposited using chemical vapor deposition. The quality of Ge layers was examined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution x-ray diffraction (HRXRD) measurements. The defect density was evaluated using etch pit density measurements. We have obtained lowest dislocation density (5×105 cm-2) Ge films on the nanopatterned Si structures. The full width half maximum peaks of the reciprocal space maps of Ge epilayers on the nanopatterned Si showed 93 arc sec. We were able to get rid of the crosshatch pattern on the Ge surface grown on the nanopatterned Si. We also showed that there is a significant improvement of the quality of the Ge epilayers in the nanopatterned Si compared to an unpatterned Si. We observed nearly three-order magnitude decrease in the dislocation density in the patterned compared to the unpatterned structures. The Ge epilayer in the patterned Si has a dislocation density of 5×105 cm-2 as compared to 6×108 cm-2 for unpatterned Si.

Improved Structural Quality and Carrier Decay Times in GaN Epitaxy on SiN and TiN Porous Network Templates

2006 ◽  
Vol 527-529 ◽  
pp. 1505-1508
Author(s):  
Ümit Özgür ◽  
Y. Fu ◽  
Cole W. Litton ◽  
Y.T. Moon ◽  
F. Yun ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Structural Quality ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
Porous Network ◽  
X Ray ◽  
Radiative Efficiency ◽  
Decay Times ◽  
Threading Dislocation Density

Improved structural quality and radiative efficiency were observed in GaN thin films grown by metalorganic chemical vapor deposition on in situ-formed SiN and TiN porous network templates. The room temperature carrier decay time of 1.86 ns measured for a TiN network sample is slightly longer than that for a 200 μm-thick high quality freestanding GaN (1.73 ns). The linewidth of the asymmetric X-Ray diffraction (XRD) (1012) peak decreases considerably with the use of SiN and TiN layers, indicating the reduction in threading dislocation density. However, no direct correlation is yet found between the decay times and the XRD linewidths, suggesting that point defect and impurity related nonradiative centers are the main parameters affecting the lifetime.

Fabrication of PZT Based Capacitor with SrRuO3 Electrode for Memory Device Applications

1998 ◽  
Vol 541 ◽  
Author(s):  
Ashok Kumar ◽  
H. Rahman ◽  
M. Shamsuzzoha
Keyword(s):  
Ferroelectric Properties ◽  
Ruthenium Oxide ◽  
Memory Device ◽  
Ferroelectric Material ◽  
Test System ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Transmission Electron ◽  
Device Applications

AbstractStrontium ruthenium oxide (SrRuO3) was deposited on Pt/(100)Si substrates at varying temperatures and 300 mTorr oxygen pressure using the pulsed laser deposition method and was found to be highly crystalline and textured when deposited over 450°C. After achieving highly crystalline SrRuO3 films, capacitors using the ferroelectric material - PZT (PbZr0.5Ti0.48O3) were successfully fabricated on Pt/(100)Si substrates. The ferroelectric properties of the films were determined by the RT66A Standardized Ferroelectric Test System. The structural properties of the films were analyzed by X-ray diffraction. Transmission electron microscopy was used to determine the crystallinity and quality of interfaces among different layers.

Microstructure and Physical Properties of GaN Films on Sapphire Substrates

1999 ◽  
Vol 595 ◽  
Author(s):  
Zhizhong Chen ◽  
Rong Zhang ◽  
Jianming Zhu ◽  
Bo Shen ◽  
Yugang Zhou ◽  
...  
Keyword(s):  
Physical Properties ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Band Edge Emission ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Order Of Magnitude

AbstractTransmission electron microscopy (TEM), x-ray diffraction (XRD), photoluminescence (PL) and Raman scattering measurements were applied to study the correlation between the microstructure and physical properties of the GaN films grown by light radiation heating metalorganic chemical vapor deposition (LRH-MOCVD), using GaN buffer layer on sapphire substrates. When the density of the threading dislocation (TD) increases about one order of magnitude, the yellow luminescence (YL) intensity is strengthened from negligible to two orders of magnitude higher than the band edge emission intensity. The full width of half maximum (FWHM) of the GaN (0002) peak of the XRD rocking curve was widened from 11 min to 15 min, and in Raman spectra, the width of E2 mode is broadened from 5 cm-1 to 7 cm-1. A “zippers” structure at the interface of GaN/sapphire was observed by high-resolution electron microscope (HREM). Furthermore the origins of TD and relationship between physical properties and microstructures combining the growth conditions are discussed.

Strain Evaluation of GaAs Layers Grown on Ultrahigh-Pressure-Annealed Strain-Free GaAs-On-Si Structures

1997 ◽  
Vol 486 ◽  
Author(s):  
Takehito Jimbo ◽  
Hiroshi Ishiwara
Keyword(s):  
Chemical Vapor ◽  
Xrd Analysis ◽  
Gaas Layer ◽  
Ultrahigh Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Gaas On Si ◽  
Gaas Films ◽  
Regeneration Effect

AbstractIn order to form strain-free GaAs films on Si substrates, GaAs-on-Si structures have been formed by molecular beam epitaxy (MBE) or metalorganic chemical vapor deposition (MOCVD) and subsequently annealed under ultrahigh pressure at 2 GPa. The samples were then reannealed at atmospheric pressure in order to investigate the regeneration effect of strain in the GaAs films. It was found from X-ray diffraction (XRD) analysis and photoluminescence (PL) measurement that in the reannealed samples the strain near the surface of GaAs film was smaller than that near the interface with Si. Finally, additional GaAs layers were grown using MBE on both as-grown and strain-free GaAs-on-Si structures and it was found that the residual strain in the GaAs layer on strain-free GaAs-on-Si structure was smaller than in the as-grown case.

scholarly journals On the Study of Dislocation Density in MBE GaSb-Based Structures

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1074
Author(s):  
Agata Jasik ◽  
Dariusz Smoczyński ◽  
Iwona Sankowska ◽  
Andrzej Wawro ◽  
Jacek Ratajczak ◽  
...  
Keyword(s):  
High Resolution ◽  
Dislocation Density ◽  
Measurement Techniques ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
Gaas Sample ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Threading Dislocation Density

The results of the study on threading dislocation density (TDD) in homo- and heteroepitaxial GaSb-based structures (metamorphic layers, material grown by applying interfacial misfit array (IMF) and complex structures) deposited using molecular beam epitaxy are presented. Three measurement techniques were considered: high-resolution x-ray diffraction (HRXRD), etch pit density (EPD), and counting tapers on images obtained using atomic force microscopy (AFM). Additionally, high-resolution transmission electron microscopy (HRTEM) was used for selected samples. The density of dislocations determined using these methods varied, e.g., for IMF-GaSb/GaAs sample, were 6.5 × 108 cm−2, 2.2 × 106 cm−2, and 4.1 × 107 cm−2 obtained using the HRXRD, EPD, and AFM techniques, respectively. Thus, the value of TDD should be provided together with information about the measurement method. Nevertheless, the absolute value of TDD is not as essential as the credibility of the technique used for optimizing material growth. By testing material groups with known parameters, we established which techniques can be used for examining the dislocation density in GaSb-based structures.

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