Mg Segregation, Difficulties of P-Doping in GaN

1999 ◽  
Vol 595 ◽  
Author(s):  
Z. Liliental-Weber ◽  
M. Benamara ◽  
W. Swider ◽  
J. Washburn ◽  
I. Grzegory ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Bulk Crystals ◽  
Planar Defects ◽  
Polar Direction ◽  
Internal Surfaces ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
Metal Organic

AbstractTransmission electron microscopy has been used to study defects formed in Mg-doped GaN crystals. Three types of crystals have been studied: bulk crystals grown by a high pressure and high temperature process with Mg added to the Ga solution and two types of crystals grown by metal-organic chemical vapor deposition (MOCVD) where Mg was either delta-doped or continuously doped. Spontaneous ordering was observed in bulk crystals. The ordering consists of Mg rich planar defects on basal planes separated by 10.4 nm and occurs only for growth in the N to Ga polar direction (000 1N polarity). These planar defects exhibit the characteristics of stacking faults with a shift vector of a 1/3 [1100] +c/2 but some other features identify these defects as inversion domains. Different type of defects were formed on the opposite site of the crystal (Ga to N polar direction), where the growth rate is also an order of magnitude faster compared to the growth with N-polarity. These defects are three-dimensional: pyramidal and rectangular, empty inside with Mg segregation on internal surfaces. The same types of defects seen for the two growth polarities in the bulk crystals were also observed in the MOCVD grown GaN samples with Mg delta doping, but were not observed in the crystals where Mg was added continuously.

scholarly journals Mg Segregation, Difficulties of P-Doping in GaN

2000 ◽  
Vol 5 (S1) ◽  
pp. 500-506
Author(s):  
Z. Liliental-Weber ◽  
M. Benamara ◽  
W. Swider ◽  
J. Washburn ◽  
I. Grzegory ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Bulk Crystals ◽  
Planar Defects ◽  
Polar Direction ◽  
Internal Surfaces ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
Metal Organic

Transmission electron microscopy has been used to study defects formed in Mg-doped GaN crystals. Three types of crystals have been studied: bulk crystals grown by a high pressure and high temperature process with Mg added to the Ga solution and two types of crystals grown by metal-organic chemical vapor deposition (MOCVD) where Mg was either delta-doped or continuously doped. Spontaneous ordering was observed in bulk crystals. The ordering consists of Mg rich planar defects on basal planes separated by 10.4 nm and occurs only for growth in the N to Ga polar direction (000 N polarity). These planar defects exhibit the characteristics of stacking faults with a shift vector of a 1/3 [1 00] +c/2 but some other features identify these defects as inversion domains. Different type of defects were formed on the opposite site of the crystal (Ga to N polar direction), where the growth rate is also an order of magnitude faster compared to the growth with N-polarity. These defects are three-dimensional: pyramidal and rectangular, empty inside with Mg segregation on internal surfaces. The same types of defects seen for the two growth polarities in the bulk crystals were also observed in the MOCVD grown GaN samples with Mg delta doping, but were not observed in the crystals where Mg was added continuously.

Structural and electronic properties of defects in semiconductors

1995 ◽  
Vol 53 ◽  
pp. 4-5
Author(s):  
J.L. Batstone
Keyword(s):  
Semiconductor Device ◽  
Chemical Vapor ◽  
Misfit Strain ◽  
Organic Chemical ◽  
Extended Defects ◽  
Transmission Electron ◽  
Semiconductor Thin Films ◽  
Wide Range ◽  
Metal Organic ◽  
Film Substrate

The development of growth techniques such as metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy during the last fifteen years has resulted in the growth of high quality epitaxial semiconductor thin films for the semiconductor device industry. The III-V and II-VI semiconductors exhibit a wide range of fundamental band gap energies, enabling the fabrication of sophisticated optoelectronic devices such as lasers and electroluminescent displays. However, the radiative efficiency of such devices is strongly affected by the presence of optically and electrically active defects within the epitaxial layer; thus an understanding of factors influencing the defect densities is required.Extended defects such as dislocations, twins, stacking faults and grain boundaries can occur during epitaxial growth to relieve the misfit strain that builds up. Such defects can nucleate either at surfaces or thin film/substrate interfaces and the growth and nucleation events can be determined by in situ transmission electron microscopy (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.

Microstructural Characterization of GaN Grown on SiC

2019 ◽  
Vol 25 (6) ◽  
pp. 1383-1393
Author(s):  
Sabyasachi Saha ◽  
Deepak Kumar ◽  
Chandan K. Sharma ◽  
Vikash K. Singh ◽  
Samartha Channagiri ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Raman Spectroscopy ◽  
Surface Morphology ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Organic Chemical ◽  
Nucleation Layer ◽  
Transmission Electron ◽  
Vapor Deposition Technique ◽  
Metal Organic

AbstractGaN films have been grown on SiC substrates with an AlN nucleation layer by using a metal organic chemical vapor deposition technique. Micro-cracking of the GaN films has been observed in some of the grown samples. In order to investigate the micro-cracking and microstructure, the samples have been studied using various characterization techniques such as optical microscopy, atomic force microscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy (TEM). The surface morphology of the AlN nucleation layer is related to the stress evolution in subsequent overgrown GaN epilayers. It is determined via TEM evidence that, if the AlN nucleation layer has a rough surface morphology, this leads to tensile stresses in the GaN films, which finally results in cracking. Raman spectroscopy results also suggest this, by showing the existence of considerable tensile residual stress in the AlN nucleation layer. Based on these various observations and results, conclusions or propositions relating to the microstructure are presented.

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.

scholarly journals Horizontal Assembly of Single Nanowire Diode Fabricated byp-nJunction GaN NW Grown by MOCVD

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ji-Hyeon Park ◽  
Suthan Kissinger ◽  
Yong Ho Ra ◽  
Kang San ◽  
Min Ji Park ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Uv Light ◽  
Light Exposure ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Chemical Vapor Deposition Method ◽  
Transport Studies ◽  
Transmission Electron ◽  
Metal Organic ◽  
Parallel Assembly

Uniaxiallyp-njunction gallium nitride nanowires have been synthesized via metal-organic chemical vapor deposition method. Nanowires prepared on Si(111) substrates were found to grow perpendicular to the substrate, and the transmission electron microscopy studies demonstrated that the nanowires had singlecrystalline structures with a <0001> growth axis. The parallel assembly of thep-njunction nanowire was prepared on a Si substrate with a thermally grown SiO2layer. The transport studies of horizontal gallium nitride nanowire structures assembled fromp- andn-type materials show that these junctions correspond to well-definedp-njunction diodes. Thep-njunction devices based on GaN nanowires suspended over the electrodes were fabricated and their electrical properties were investigated. The horizontally assembled gallium nitride nanowire diodes suspended over the electrodes exhibited a substantial increase in conductance under UV light exposure. Apart from the selectivity to different light wavelengths, high responsivity and extremely short response time have also been obtained.

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