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).

Epitaxial thin films of PbTiO3/SnO2 heterostructures on sapphire

1994 ◽  
Vol 9 (12) ◽  
pp. 3108-3112 ◽  
Author(s):  
H.L.M. Chang ◽  
H. Zhang ◽  
Z. Shen ◽  
Q. Wang
Keyword(s):  
Material Selection ◽  
Single Layer ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Epitaxial Thin Films ◽  
Ferroelectric Films ◽  
Epitaxial Relationship ◽  
Transmission Electron ◽  
Wide Range ◽  
Metal Organic

Epitaxial films of single-layer SnO2 and PbTiO3/SnO2 heterostructures were obtained on (0001) sapphire (α-Al2O3) substrates by metal-organic chemical vapor deposition. X-ray diffraction and transmission electron microscopy were used to characterize the structural properties of these films. The epitaxial relationship for the heterostructure PbTiO3/SnO2/sapphire was found to be (111) [011]PbTiO3 ‖ (100) [001]SnO2 ‖ (0001) [1100]α-Al2O3. The fact that epitaxial ferroelectric films were obtainable in such a structurally highly heterogeneous system suggests that a wide range of material selection is possible in exploring the kind of applications that need to utilize epitaxial ferroelectric films in a multilayered heterostructure.

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.

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.

TEM Study of MOCVD Grown InSb/GaAs Heterostructures with and without TMIn Predeposited Layers

1994 ◽  
Vol 340 ◽  
Author(s):  
L. H. Kuo ◽  
Susan Z. Hua ◽  
L. Salamanca-Riba ◽  
D. L. Partin ◽  
L. Green ◽  
...  
Keyword(s):  
Vapor Deposition ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Threading Dislocations ◽  
High Quality ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Metal Organic ◽  
Step Growth ◽  
Organic Chemical Vapor Deposition

ABSTRACTHigh quality InSb epilayers were grown on GaAs substrates by metal organic chemical vapor deposition using a two-step growth procedure involving trimethal indium (TMIn) predeposition. From transmission electron microscopy studies, we found that an interdiffusion layer of thickness of 10 Å forms at the interface when the substrate is exposed to TMIn for approximately 6 secs prior to the growth of the InSb filns. Hall mobilities up to σ 52,000 cm2/V-s were obtained at 300 K on a 2.1-μm-thick InSb heteroepitaxial film. In contrast, samples without TMIn predeposition showed polycrystallinity of the InSb films grown on single crystalline GaAs substrates. The effect. of TMNIn predeposition is to minimize the misorientation of the grains, suppress the polycrystallinity, decrease the density of threading dislocations, and increase the electron mobilities in the films. However, we found that too much TMIn predeposition gives rise t.o an intermixing layer at the InSb/GaAs interface which deteriorates the film quality. Details of the effect of the TMIn predeposition on the microstructure of InSb/GaAs with different predeposition times (zero, 6, and 12 secs) are discussed.

scholarly journals Microstrip Array Ring FETs with 2D p-Ga2O3 Channels Grown by MOCVD

Photonics ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 578
Author(s):  
Manijeh Razeghi ◽  
Junhee Lee ◽  
Lakshay Gautam ◽  
Jean-Pierre Leburton ◽  
Ferechteh H. Teherani ◽  
...  
Keyword(s):  
Field Effect Transistors ◽  
Chemical Vapor ◽  
Drain Current ◽  
Significant Advance ◽  
Growth Time ◽  
Organic Chemical ◽  
Transmission Electron ◽  
Metal Organic ◽  
P Type ◽  
Type Conduction

Gallium oxide (Ga2O3) thin films of various thicknesses were grown on sapphire (0001) substrates by metal organic chemical vapor deposition (MOCVD) using trimethylgallium (TMGa), high purity deionized water, and silane (SiH4) as gallium, oxygen, and silicon precursors, respectively. N2 was used as carrier gas. Hall measurements revealed that films grown with a lower VI/III ratio had a dominant p-type conduction with room temperature mobilities up to 7 cm2/Vs and carrier concentrations up to ~1020 cm−3 for thinner layers. High resolution transmission electron microscopy suggested that the layers were mainly κ phase. Microstrip field-effect transistors (FETs) were fabricated using 2D p-type Ga2O3:Si, channels. They achieved a maximum drain current of 2.19 mA and an on/off ratio as high as ~108. A phenomenological model for the p-type conduction was also presented. As the first demonstration of a p-type Ga2O3, this work represents a significant advance which is state of the art, which would allow the fabrication of p-n junction based devices which could be smaller/thinner and bring both cost (more devices/wafer and less growth time) and operating speed (due to miniaturization) advantages. Moreover, the first scaling down to 2D device channels opens the prospect of faster devices and improved heat evacuation.

Pinning of 90° domain boundaries at interface dislocations in BaTiO3/LaAIO3 {100}

1996 ◽  
Vol 54 ◽  
pp. 124-125
Author(s):  
Z.-R. Dai ◽  
Z.L. Wang ◽  
X.F. Duan ◽  
J. Zhang
Keyword(s):  
Thin Films ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Epitaxial Thin Films ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Potential Applications ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Epitaxially grown BaTiO3 thin films have potential applications in microelectronics and integrated photonics. The ferroelectric property of this material is largely determined by the domain structure. It is believed that the structure of the substrate would have profound effect on the quality of BaTiO3 epitaxial thin films. This paper reports our studies on the pinning of 90° domain boundaries at interface dislocations.Epitaxial BaTiO3 thin films were deposited on single crystalline LaAIO3 (100) substrates at 800°C by metal-organic chemical vapor deposition (MOCVD). Cross-section specimens of the films were studied at 200 kV using an JEOL 2010 high-resolution transmission electron microscope (HRTEM).

MOCVD Growth of Ga(Al)N/InGaN/Ga(Al)N-Heterostructures: Influence of the Buffer Layer Al-Concentration and Growth Duration on the In-Incorporation in InGaN

2001 ◽  
Vol 680 ◽  
Author(s):  
Marco Schowalter ◽  
Brigitte Neubauer ◽  
Andreas Rosenauer ◽  
Dagmar Gerthsen ◽  
Oliver Schön ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Organic Chemical ◽  
Growth Duration ◽  
Mocvd Growth ◽  
Transmission Electron ◽  
Metal Organic ◽  
Composition Fluctuations ◽  
Organic Chemical Vapor Deposition

ABSTRACTTransmission electron microscopy (TEM) has been applied to analyze the thickness and the In-concentration of InGaN layers in GaN/InGaN/GaN- and AlGaN/InGaN/AlGaN-quantum well (QW) structures. Two series of samples were grown by metal organic chemical vapor deposition varying either only the growth duration for the InGaN QW or by changing the Al- concentration in the buffer layers at unaltered InGaN growth conditions. A rising average In- concentration from 6.5 to 15.4 % and a decreasing growth rate are observed with increasing growth duration. The increase of the Al-concentration in the buffer layers from 0 to 36 % strongly affects the In-incorporation during the InGaN growth, which decreases from 17.5 to 2.5 %. All samples are characterized by an inhomogeneous In-distribution containing In-rich agglomerates with a size of only a few nanometers and less pronounced composition fluctuations on a scale of 100 nm.

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