Optimization of GaN Barriers During the Growth of InGaN/GaN Quantum Wells at Low Temperature

2008 ◽  
Vol 1108 ◽  
Author(s):  
Kalyan R Kasarla ◽  
Wenyu Chiang ◽  
Ronak Rahimi ◽  
D. Korakakis
Keyword(s):  
Low Temperature ◽  
Quantum Wells ◽  
Defect Density ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Organic Vapor ◽  
Atomic Force ◽  
Metal Organic ◽  
Tapping Mode Afm ◽  
Surface Morphologies

AbstractInGaN/GaN MQWs are grown on c-plane sapphire substrates using a low pressure metal organic vapor phase epitaxy (MOVPE) system. Trimethylgallium (TMGa), Triethylgallium (TEGa), Trimethylindium (TMIn) and ammonia were used as precursors for Ga, In and N, respectively and the growths were carried out at low temperature. Structural properties of grown MQWs are characterized using atomic force microscopy (AFM), and scanning electron microscope (SEM) and x-ray diffraction technique (XRD) is used to calculate the Indium incorporation in these MQWs. Surface morphologies over large areas of InGaN/GaN MQWs are observed using the tapping mode AFM; results indicate the surface roughness depends on the barrier thickness. Density of V- defects, effect of barrier width on the surface morphology and also on V-defect density will be presented and discussed.

Growth of High Quality c-plane AlN on a-plane Sapphire

2009 ◽  
Vol 1202 ◽  
Author(s):  
Reina Miyagawa ◽  
Jiejun Wu ◽  
Hideto Miyake ◽  
Kazumasa Hiramatsu
Keyword(s):  
Vapor Phase ◽  
Vapor Phase Epitaxy ◽  
Hydride Vapor Phase Epitaxy ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Organic Vapor ◽  
Atomic Force ◽  
Metal Organic ◽  
Dislocations Density ◽  
Reactor Pressure

Abstractc-plane (0001) AlN layers were grown on sapphire (11-20) and (0001) substrates by hydride vapor phase epitaxy (HVPE) and metal-organic vapor phase epitaxy (MOVPE), respectively. The growth temperatures were adjusted from 1430-1500 °C and the reactor pressure was kept constant at 30 Torr. Mirror and flat c-plane AlN were obtained grown on both a-plane and c-plane sapphire. Crystalline quality and surface roughness are improved with increasing growth temperature, detected by high resolution X-ray diffraction (HRXRD) and atomic force microscopy (AFM). The Full widths at half maximum (FWHM) values of (10-12) diffraction are 519 and 1219 arcsec for c-plane AlN grown on a-plane sapphire and c-plane sapphire, respectively. It indicates that a-plane sapphire substrate benefits to decrease dislocations density.

Dielectric Properties of Sol-Gel Derived MgAl2O4 Thin Films

2012 ◽  
Vol 151 ◽  
pp. 314-318
Author(s):  
Ching Fang Tseng ◽  
Cheng Hsing Hsu ◽  
Chun Hung Lai
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Dissipation Factor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Preheating Temperature ◽  
Surface Morphologies

This paper describes microstructure characteristics of MgAl2O4 thin films were deposited by sol-gel method with various preheating temperatures and annealing temperatures. Particular attention will be paid to the effects of a thermal treatment in air ambient on the physical properties. The annealed films were characterized using X-ray diffraction. The surface morphologies of treatment film were examined by scanning electron microscopy and atomic force microscopy. At a preheating temperature of 300oC and an annealing temperature of 700oC, the MgAl2O4 films with 9 μm thickness possess a dielectric constant of 9 at 1 kHz and a dissipation factor of 0.18 at 1 kHz.

Formation of Self-Assembled Nanometer-Scale InP Islands on Silicon Substrates

2000 ◽  
Vol 618 ◽  
Author(s):  
A.S. Bakin ◽  
D. Piester ◽  
H.-H. Wehmann ◽  
A.A. Ivanov ◽  
A. Schlachetzki ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Atomic Force Microscopy ◽  
Vapor Phase ◽  
Three Dimensional ◽  
Nanometer Scale ◽  
Silicon Substrates ◽  
Force Microscopy ◽  
Organic Vapor ◽  
Atomic Force ◽  
Metal Organic

ABSTRACTThree-dimensional islands of InP have been reproducibly grown in the Stranski-Krastanow growth mode on Si (001) and (111) by using metal-organic vapor phase epitaxy in order to obtain nanometer-scale quantum dots. Atomic-force microscopy was used to determine the morphology of the samples and to evaluate the dimensions of the islands. Formation of three-dimensional islands with densities as high as 2.5×1010 cm−2 and small sizes have been observed. The evolution of island morphology is explained in terms of strain-relaxing mechanisms at the first stages of InP/Si heteroepitaxy.

Gallium Nitride Growth Using Diethylgallium Chloride as an Alternative Gallium Source

1998 ◽  
Vol 537 ◽  
Author(s):  
Ling Zhang ◽  
Rong Zhang ◽  
Marek P. Boleslawski ◽  
T.F. Kuech
Keyword(s):  
Growth Conditions ◽  
Rocking Curve ◽  
X Ray ◽  
Force Microscopy ◽  
Organic Vapor ◽  
Atomic Force ◽  
Curve Line ◽  
Metal Organic ◽  
Increasing Temperature ◽  
Trimethyl Gallium

AbstractMetal organic vapor phase epitaxy (MOVPE) of GaN has been carried out using diethyl gallium chloride (DEGaCI) and ammonia. The growth rate and efficiency of the DEGaCl-based growth decreases with increasing temperature when compared to trimethyl gallium (TMG)-based growth under similar conditions. Both low temperature buffer and the high temperature GaN layers were grown using the DEGaCI-NH3 precursor combination on the basal plane of sapphire and compared to similar structures grown using TMG and NH3. DEGaCl-based growth reveals an improved growth behavior under identical growth conditions to the conventional TMGa and ammonia growth. X-ray, Hall, and atomic force microscopy (AFM) measurements have been carried out on these samples providing a direct comparison of materials properties associated with these growth precursors. For the DEGaCl-based growth, the x-ray rocking curve line width, using the (0002) reflection, is as low as 300 arcsec on a 2.5-micron thick film. A RMS surface roughness of ∼0.5nm measured over a 10x10 micron area.

The Initial Stages of Growth of Ordered GaInP and GaInAs Grown by Metal Organic Vapor Phase Epitaxy

1999 ◽  
Vol 583 ◽  
Author(s):  
M. C. Hanna ◽  
A. Mascarenhas ◽  
Hyeonsik M. Cheong
Keyword(s):  
Raman Spectroscopy ◽  
Atomic Force Microscopy ◽  
Direct Evidence ◽  
Force Microscopy ◽  
Step Flow ◽  
Organic Vapor ◽  
Stages Of Growth ◽  
Atomic Force ◽  
Metal Organic ◽  
Step Flow Growth

AbstractWe have used atomic force microscopy (AFM) and Raman spectroscopy to investigate the development of the surface morphology of (001) direct and vicinal GaInP and GaInAs grown under conditions to produce strong CUPtB ordering. Raman spectroscopy provided direct evidence of CuPtB ordering in layers as thin as 10 nm for GaInP and 5 nm for GaInAs. We find that the morphology of GaInP and GaInAs on (001)6B substrates consists of ridges, which are aligned predominately along the [110] direction (A-direction). These ridges are well developed even at layer thicknesses of 2 nm, and their sides consist of step-bunches and near (001) terraces. On (001) direct substrates, the GaInP morphology is similar to that obtained on 6B substrates, although the step bunches have no preferential orientation, while GaInAs (001) growth proceeds by a combination of 2D-island and step flow growth. We discuss possible reasons for the differences in the morphology of ordered GaInP and GaInAs. The results of this work suggest it may be difficult to produce abrupt heterointerfaces in structures containing ordered GalnP and GaInAs alloys.

scholarly journals Gallium Nitride Growth Using Diethylgallium Chloride as an Alternative Gallium Source

1999 ◽  
Vol 4 (S1) ◽  
pp. 351-356
Author(s):  
Ling Zhang ◽  
Rong Zhang ◽  
Marek P. Boleslawski ◽  
T.F. Kuech
Keyword(s):  
Growth Conditions ◽  
Rocking Curve ◽  
X Ray ◽  
Force Microscopy ◽  
Organic Vapor ◽  
Atomic Force ◽  
Curve Line ◽  
Metal Organic ◽  
Increasing Temperature ◽  
Trimethyl Gallium

Metal organic vapor phase epitaxy (MOVPE) of GaN has been carried out using diethyl gallium chloride (DEGaCl) and ammonia. The growth rate and efficiency of the DEGaCl-based growth decreases with increasing temperature when compared to trimethyl gallium (TMG)-based growth under similar conditions. Both low temperature buffer and the high temperature GaN layers were grown using the DEGaCl-NH3 precursor combination on the basal plane of sapphire and compared to similar structures grown using TMG and NH3. DEGaCl-based growth reveals an improved growth behavior under identical growth conditions to the conventional TMGa and ammonia growth. X-ray, Hall, and atomic force microscopy (AFM) measurements have been carried out on these samples providing a direct comparison of materials properties associated with these growth precursors. For the DEGaCl-based growth, the x-ray rocking curve line width, using the (0002) reflection, is as low as 300 arcsec on a 2.5-micron thick film. A RMS surface roughness of ∼0.5nm measured over a 10×10 micron area.

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