scholarly journals Review of polarity determination and control of GaN

2004 ◽  
Vol 9 ◽  
Author(s):  
M. Sumiya ◽  
S. Fuke
Keyword(s):  
Molecular Beam ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Hydride Vapor Phase Epitaxy ◽  
Nitride Semiconductors ◽  
Sapphire Substrates ◽  
Polarity Determination ◽  
And Control ◽  
Systematic Control ◽  
Growth Methods

Polarity issues affecting III-V nitride semiconductors are reviewed with respect to their determination and control. A set of conditions crucial to the polarity control of GaN is provided for each of the following growth techniques; molecular beam epitaxy (MBE), pulsed laser deposition (PLD) and hydride vapor phase epitaxy (HVPE). Although GaN films might have been deposited by identical growth methods using the same buffer layer technologies, there is often a conflict between the resulting polarities achieved by different research groups. In this paper, we present the implications of the conditions used in each of the processes used for two-step metalorganic chemical vapor deposition (MOCVD), demonstrating systematic control of the polarity of GaN films on sapphire substrates. The potential for confusion in polarity control will be explained, taking into account the implications clarified in our studies. The correlation between the polarity and the growth conditions will be discussed in order to provide a mechanism for the determination and control of the crystal polarity during the growth of GaN films.

Possibilities of Monte Carlo simulation for examination of nanowhisker growth

2010 ◽  
Vol 82 (11) ◽  
pp. 2017-2025 ◽  
Author(s):  
Alla G. Nastovjak ◽  
Igor G. Neizvestny ◽  
Nataliya L. Shwartz
Keyword(s):  
Monte Carlo ◽  
Vapor Deposition ◽  
Molecular Beam ◽  
Whisker Growth ◽  
Kinetic Monte Carlo ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Vapor Liquid Solid ◽  
Whisker Morphology ◽  
Deposition Conditions

The kinetic Monte Carlo (MC) model of nanowhisker (NW) growth is suggested. Two variants of growth are possible in the model—molecular beam epitaxy (MBE) and chemical vapor deposition (CVD). The effect of deposition conditions and growth regimes on the whisker morphology was examined within the framework of the vapor–liquid–solid (VLS) mechanism. A range of model growth conditions corresponding to NW and nanotube formation was determined. The suggested MC model was used for analyses of the morphology of the catalyst–whisker interface and for examination of Si–Ge whisker growth.

scholarly journals Спонтанное формирование кластеров In в эпитаксиальных слоях InN, выращенных методом молекулярно-пучковой эпитаксии

2018 ◽  
Vol 44 (4) ◽  
pp. 42
Author(s):  
Т.А. Комиссарова ◽  
В.Н. Жмерик ◽  
С.В. Иванов
Keyword(s):  
Molecular Beam ◽  
Indium Nitride ◽  
Growth Conditions ◽  
Nitrogen Plasma ◽  
Nitrogen Flow ◽  
Model Approximation ◽  
Mbe Growth ◽  
Flow Rates ◽  
Sapphire Substrates ◽  
The Magnetic Field

AbstractWe have studied the influence of growth conditions on the number of metallic indium clusters formed spontaneously in indium nitride (InN) layers grown by nitrogen plasma-assisted molecular-beam epitaxy (PAMBE). InN epilayers of N-and In-polarity were grown on c-sapphire substrates and GaN and AlN templates, respectively. N-polar layers were obtained in the standard PAMBE regime, while In-polar layers were grown using a three-stage regime including the stages of epitaxy with enhanced atomic migration and interruption of growth under nitrogen flow. A series of samples were prepared at various growth temperatures and relative In/N flow rates. Measurement of the magnetic-field dependences of the Hall-effect coefficient and its model approximation were used to determine the percentage content of In clusters in various InN layers and the minimum amount of such inclusions that can be achieved by varying the conditions of MBE growth.

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.

Monitoring and Control in Vapor phase Epitaxy

1997 ◽  
Vol 502 ◽  
Author(s):  
T. P. Pearsall
Keyword(s):  
Control System ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Temperature Control System ◽  
Monitoring And Control ◽  
Non Invasive ◽  
Innovative Solutions ◽  
Precision And Accuracy ◽  
And Control

ABSTRACTMonitoring and control in epitaxy based on chemical vapor deposition is a challenge created by growth conditions that often preclude more common sensors like thermocouples and mass spectrometry. We report results of experiments to measure and control temperature and flux by non-invasive optical sensing. We have developed a temperature control system with precision and accuracy better that 5°C. Satisfactory control of flux poses difficulties that will require innovative solutions before a useful control system can be developed.

Development of HgCdTe for LWIR Imagers

1986 ◽  
Vol 90 ◽  
Author(s):  
Joseph L. Schmit
Keyword(s):  
Room Temperature ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Zone Melting ◽  
Phase Growth ◽  
Large Area ◽  
Long Wavelength ◽  
Atmospheric Window ◽  
Long Wavelength Infrared ◽  
Growth Methods

ABSTRACTThis paper provides a historical perspective on the emergency of HgCdTe as the material of choice for long wavelength infrared (LWIR) imagers. The need for devices which see room temperature objects through the atmospheric window actually drove the development of this material. The lack of elemental or compound semiconductors having the desired wavelength response forced the choice of the alloy semiconductor, HgCdTe. The development of this material in several countries and companies beginning in the late 1950's is traced. The crystal growth methods used to grow HgCdTe have included melt growth techniques such as Bridgman, zone-melting, quench-anneal and slushgrowth. The solution growth techniques include growth from HgTe-rich, Te-rich and Hg-rich solutions. Vapor phase growth has included evaporation, sputtering, molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD). No perfect method has yet been developed, but several have provided material for the large area arrays needed for modern imagers.

scholarly journals Characteristics of Deep Centers Observed in n-GaN Grown by Reactive Molecular Beam Epitaxy

2000 ◽  
Vol 5 (S1) ◽  
pp. 943-949 ◽  
Author(s):  
Z-Q. Fang ◽  
D. C. Look ◽  
Wook Kim ◽  
H. Morkoç
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Deep Level ◽  
Strong Electric Field ◽  
Chemical Vapor ◽  
Hydride Vapor Phase Epitaxy ◽  
Electric Field Effects ◽  
Deep Centers ◽  
Si Doped ◽  
Transient Spectroscopy

Deep centers in Si-doped n-GaN samples grown on sapphire by reactive molecular beam epitaxy, using different ammonia flow rates (AFRs), have been studied by deep level transient spectroscopy. In addition to five electron traps, which were also found in n-GaN layers grown by both metalorganic chemical-vapor deposition and hydride vapor-phase epitaxy, two new centers C1 (0.43-0.48 eV) and E1 (0.25 eV) have been observed. C1, whose parameters show strong electric-field effects and anomalous electron capture kinetics, might be associated with dislocations. E1, which is very dependent on the AFR, exhibits an activation energy close to that of a center created by electron irradiation and is believed to be a defect complex involving VN.

Non-Polar GaN/AlN Superlattices on A-plane AlN (500nm) Buffer Layers Grown by RF-MBE

2004 ◽  
Vol 831 ◽  
Author(s):  
Takayuki Morita ◽  
Akihiko Kikuchi ◽  
Katsumi Kishino
Keyword(s):  
Molecular Beam ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates ◽  
Frequency Plasma ◽  
Diffraction Peaks ◽  
Rich Side

ABSTRACTThe growth conditions of A-plane AlN and GaN epitaxial layers by radio-frequency plasma assisted molecular beam epitaxy on R-plane sapphire substrates were investigated. The growth temperature and V/III supply ratio dependency on structural quality and surface roughness was described. The optimum V/III ratio for A-plane GaN and AlN layers was shifted to nitrogen rich side compared to the C-plane layers. A-plane GaN/AlN superlattices (SLs) were also grown on R-plane sapphire substrates. The X-ray diffraction peaks from a primary and a 1st satellite were observed. From a comparison of low temperature photoluminescence peak wavelength between A-plane and C-plane SLs, the built-in electrostatic field originated from spontaneous and piezoelectric polarization is negligible for A-plane SLs.

Characteristics of Deep Centers Observed in n-GaN Grown by Reactive Molecular Beam Epitaxy

1999 ◽  
Vol 595 ◽  
Author(s):  
Z-Q. Fang ◽  
D. C. Look ◽  
Wook Kim ◽  
H. Morkoç
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Deep Level ◽  
Strong Electric Field ◽  
Chemical Vapor ◽  
Hydride Vapor Phase Epitaxy ◽  
Electric Field Effects ◽  
Deep Centers ◽  
Si Doped ◽  
Transient Spectroscopy

AbstractDeep centers in Si-doped n-GaN samples grown on sapphire by reactive molecular beam epitaxy, using different ammonia flow rates (AFRs), have been studied by deep level transient spectroscopy. In addition to five electron traps, which were also found in n-GaN layers grown by both metalorganic chemical-vapor deposition and hydride vapor-phase epitaxy, two new centers C1 (0.43-0.48 eV) and E1 (0.25 eV) have been observed. C1, whose parameters show strong electric-field effects and anomalous electron capture kinetics, might be associated with dislocations. E1, which is very dependent on the AFR, exhibits an activation energy close to that of a center created by electron irradiation and is believed to be a defect complex involving VN.

Photoluminescence in wurtzite GaN containing carbon

2005 ◽  
Vol 892 ◽  
Author(s):  
Michael A. Reshchikov ◽  
Random H. Patillo ◽  
Kathleen C. Travis
Keyword(s):  
Chemical Vapor ◽  
Growth Conditions ◽  
Shallow Donor ◽  
Clear Correlation ◽  
Acceptor Pair ◽  
Deep Acceptor ◽  
Shallow Acceptor ◽  
Low Intensity ◽  
Sapphire Substrates ◽  
Donor Acceptor

AbstractWe studied photoluminescence (PL) from a set of GaN layers grown on sapphire substrates by metalorganic chemical vapor deposition with the concentration of carbon varied by the growth conditions. One of the remarkable features in these samples is the extremely low intensity of the shallow donor-acceptor pair band. Analysis of the PL data gives the shallow acceptor concentration of less than 1014 cm-3 in most of the C-doped GaN layers. This result shows that C does not form a shallow acceptor, CN, in appreciable concentrations in wurtzite GaN. As for the YL band, there is no clear correlation between its intensity and the degree of C-doping. The question of identification of the deep acceptor responsible for the YL band in undoped and C-doped GaN still remains to be solved.

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