scholarly journals HREM at orthogonal projections of GaAs islands on silicon

1989 ◽  
Vol 47 ◽  
pp. 586-587
Author(s):  
F. A. Ponce ◽  
C. J. D. Hetherington
Keyword(s):  
Three Dimensional ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Silicon Substrates ◽  
Orthogonal Projections ◽  
Nominal Thickness ◽  
Gaas Films ◽  
Metal Organic ◽  
Trimethyl Gallium

HREM studies typically examine only one projection of a structure and information in the electron beam direction is lost. In most cases, the structure in this direction is uniform and already known, but in others a second projection needs to be observed. This could involve preparing a second specimen sectioned at right angles to the first, or as described here, tilting a specimen through ±45° and observing the same volume in orthogonal projections. The specimen used here was of GaAs islands on <001> silicon, examined in the Atomic Resolution Microscope at LBL.In the effort to grow defect-free GaAs films on silicon substrates, understanding of the early stages of growth is required. For this experiment we chose a specimen of ultra-thin GaAs grown on silicon substrate by metal-organic chemical vapor deposition (MOCVD). The GaAs was grown at 550°C for a nominal thickness of20nm from trimethyl gallium and arsine sources.The growth conditions lead to three-dimensional growth of islands bound by {111}A planes, terminated on Ga layers.

MOCVD Growth of SiC Nanowires Aiming at the Control of their Shape

2007 ◽  
Vol 26-28 ◽  
pp. 657-660 ◽  
Author(s):  
S. Takao ◽  
Hideo Kohno ◽  
Seiji Takeda
Keyword(s):  
Chemical Vapor ◽  
Growth Conditions ◽  
High Yield ◽  
Organic Chemical ◽  
Ni Catalyst ◽  
Silicon Substrates ◽  
Sic Nanowires ◽  
Mocvd Growth ◽  
Transmission Electron ◽  
Metal Organic

We report the growth of silicon carbide (SiC) nanowires on silicon substrates by metal organic chemical vapor deposition (MOCVD) using dimethylvinyllsilane [CH2CHSi(CH3)Cl2] as a source gas and metal catalysts of Ni and Fe. Various growth conditions such as the growth temperature and the pressure of the source gas are examined to achieve high yield growth of SiC nanowires and to control their shape. No SiC nanowires were formed when using Fe. In contrast, by using Ni catalyst, numerous SiC nanowires of about 30 nm thick can be grown at the pressure of the source gas of 30 Pa at 800 °C. Their microstructure is revealed by scanning electron microscopy (SEM) and transmission electron microscope (TEM).

Ingan Quantum Dots Fabricated On Aigan Surfaces -Growth Mechanism And Optical Propertiesh-

1997 ◽  
Vol 482 ◽  
Author(s):  
H. Hirayama ◽  
S. Tanaka ◽  
P. Ramvall ◽  
Y. Aoyagi
Keyword(s):  
Quantum Dots ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Energy Shift ◽  
Organic Chemical ◽  
Self Assembling ◽  
Atomic Force ◽  
Peak Energy ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

AbstractWe demonstrate photoluminescence from self- assembling InGaN quantum dots (QDs), which are artificially fabricated on AlGaN surfaces via metal- organic chemical vapor deposition. InGaN QDs are successfully fabricated by the growth mode transition from step- flow to three dimensional island formation by using anti-surfactant silicon on AlGaN surface. The diameter and height of the fabricated InGaN QDs are estimated to be ˜10nm and ˜5nm, respectively, by an atomic- force- microscope (AFM). Indium mole fraction of InxGal−x N QDs is controlled from x=˜0.22 to ˜0.52 by varying the growth temperature of QDs. Intense photoluminescence is observed even at room temperature from InGaN QDs embedded with the GaN capping layers. In addition, the temperature- dependent energy shift of the photoluminescence peak- energy shows a localization behavior.

Novel Design of MOCVD Reactor with Three Radial Inward Flows for Epitaxial Growth of GaN Thin Films

2011 ◽  
Vol 308-310 ◽  
pp. 1037-1040
Author(s):  
Liao Qiao Yang ◽  
Jian Zheng Hu ◽  
Zun Miao Chen ◽  
Jian Hua Zhang ◽  
Alan G. Li
Keyword(s):  
Gas Flow ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Operating Pressure ◽  
Axisymmetric Mode ◽  
Mocvd Reactor ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition ◽  
D Model

In this paper, a novel super large metal organic chemical vapor deposition (MOCVD) reactor with three inlets located on the periphery of reactor was proposed and numerical evaluation of growth conditions for GaN thin film was characterized. In this design, the converging effects of gas flow in the radial direction could counterbalance the dissipation of metal organics source. CFD was used for the mathematical solution of the fluid flow, temperature and concentration fields. A 2-D model utilizing axisymmetric mode to simulate the gas flow in a MOCVD has been developed. The growth of GaN films using TMGa as a precursor, hydrogen as carrier gas was investigated. The effects of flow rates, mass fraction of various species, operating pressure, and gravity were analyzed and discussed, respectively. The numerical simulation results show all the fields distributions were in an acceptable range.

scholarly journals Investigation of AlGaN/GaN Heterostructures Grown on Sputtered AlN Templates with Different Nucleation Layers

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4050 ◽  
Author(s):  
Chuan-Yang Liu ◽  
Ya-Chao Zhang ◽  
Sheng-Rui Xu ◽  
Li Jiang ◽  
Jin-Cheng Zhang ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Layer Growth ◽  
Organic Chemical ◽  
Propagation Mechanism ◽  
Nucleation Layer ◽  
Low Dislocation Density ◽  
Structural And Electrical Properties ◽  
Metal Organic

In this work, a sputtered AlN template is employed to grow high-quality AlGaN/GaN heterostructures, and the effects of AlN nucleation layer growth conditions on the structural and electrical properties of heterostructures are investigated in detail. The optimal growth condition is obtained with composited AlN nucleation layers grown on a sputtered AlN template, resulting in the smooth surface morphology and superior transport properties of the heterostructures. Moreover, high crystal quality GaN material with low dislocation density has been achieved under the optimal condition. The dislocation propagation mechanism, stress relief effect in the GaN grown on sputtered AlN, and metal organic chemical vapor deposition AlN nucleation layers are revealed based on the test results. The results in this work demonstrate the great potential of AlGaN/GaN heterostructures grown on sputtered AlN and composited AlN nucleation layers for microelectronic applications.

scholarly journals O-Band Emitting InAs Quantum Dots Grown by MOCVD on a 300 mm Ge-Buffered Si (001) Substrate

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2450
Author(s):  
Oumaima Abouzaid ◽  
Hussein Mehdi ◽  
Mickael Martin ◽  
Jérémy Moeyaert ◽  
Bassem Salem ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Chemical Vapor ◽  
Lattice Parameter ◽  
Organic Chemical ◽  
Silicon Substrates ◽  
Wafer Level ◽  
Si Substrate ◽  
Si Substrates ◽  
Transmission Electron ◽  
Metal Organic

The epitaxy of III-V semiconductors on silicon substrates remains challenging because of lattice parameter and material polarity differences. In this work, we report on the Metal Organic Chemical Vapor Deposition (MOCVD) and characterization of InAs/GaAs Quantum Dots (QDs) epitaxially grown on quasi-nominal 300 mm Ge/Si(001) and GaAs(001) substrates. QD properties were studied by Atomic Force Microscopy (AFM) and Photoluminescence (PL) spectroscopy. A wafer level µPL mapping of the entire 300 mm Ge/Si substrate shows the homogeneity of the three-stacked InAs QDs emitting at 1.30 ± 0.04 µm at room temperature. The correlation between PL spectroscopy and numerical modeling revealed, in accordance with transmission electron microscopy images, that buried QDs had a truncated pyramidal shape with base sides and heights around 29 and 4 nm, respectively. InAs QDs on Ge/Si substrate had the same shape as QDs on GaAs substrates, with a slightly increased size and reduced luminescence intensity. Our results suggest that 1.3 μm emitting InAs QDs quantum dots can be successfully grown on CMOS compatible Ge/Si substrates.

Analysis of the Physical and Chemical Factors Determining Compositional Variations in the MOCVD Growth of Indium Gallium Arsenide

1990 ◽  
Vol 204 ◽  
Author(s):  
Erik O. Einset ◽  
Klavs F. Jensen ◽  
Thomas F. Kuech
Keyword(s):  
Transport Model ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Lattice Parameter ◽  
Organic Chemical ◽  
Mocvd Growth ◽  
Metal Organic ◽  
Compositional Variations ◽  
Wall Depletion ◽  
Physical And Chemical

ABSTRACTWe present an analysis of compositional variations in the growth of the compound semiconductor, InxGal-xAs, by metal organic chemical vapor deposition (MOCVD). A three dimensional transport model for fluid flow, heat, and mass transfer is solved using the finite element method. The Delta Lattice Parameter (DLP) model is used to describe the thermodynamics of the solid solution, and the Hertz-Langmuir equation is used to calculate the evaporation rate of indium from the growing crystal. Wall depletion is incorporated by allowing for explicit wall deposition of In vapor throughout the reactor.Comparison of model predictions with experimental observations by MOCVD of InGaAs in a horizontal reactor suggests that transport phenomena lead to composition variations across the substrate, and that solution thermodynamics have little effect on the InAs incorporation rate at a given deposition temperature. However, thermodynamic factors appear to influence the change in indium incorporation with growth temperature.

Atomic Scale Aluminum and Strain Distribution in a Gan/AlxGa1−XN Heterostructure

1997 ◽  
Vol 482 ◽  
Author(s):  
Christian Kisielowski ◽  
Olaf Schmidt ◽  
Jinwei Yang
Keyword(s):  
Three Dimensional ◽  
Chemical Vapor ◽  
High Resolution Electron Microscopy ◽  
Atomic Scale ◽  
Organic Chemical ◽  
Well Test ◽  
Lattice Constants ◽  
Resolution Electron ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

AbstractA GaN/AlxGalxN multi-quantum well test structure with Al concentrations 0 ≤ xAl ≤ 1 was utilized to investigate the growth of AlxGal–xN barrier layers deposited by metal organic chemical vapor deposition (MOCVD). A transition from a two dimensional (2D) to a three dimensional (3D) growth mode was observed in AlxGa1–xN barriers with XAl ≥ 0.75. It is argued that the transition occurs because of growth at temperatures that are low compared with the materials melting points Tmelt. The resulting rough AlxGa1–xN surfaces can be planarized by overgrowth with GaN. Quantitative high resolution electron microscopy (HREM) was applied to measure composition and strain profiles across the GaN/AlxGa1−xN stacks at an atomic level. The measurements reveal a substantial variation of lattice constants at the AlxGa1−xN/GaN interfaces that is attributed to an Al accumulation.

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