Structural Characterization of Thick Gan Films Grown by Hydride Vapor Phase Epitaxy

1996 ◽  
Vol 423 ◽  
Author(s):  
L. T. Romano ◽  
R. J. Molnar ◽  
B. S. Krusor ◽  
G. A. Anderson ◽  
D. P. Bour ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Defect Density ◽  
Vapor Phase Epitaxy ◽  
Hydride Vapor Phase Epitaxy ◽  
Structural Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Zno Buffer Layer ◽  
Dislocation Annihilation

AbstractThe structural quality of GaN films grown by hydride vapor phase epitaxy (HVPE) was characterized by transmission electron microscopy (TEM), x-ray diffraction (XRD), and atomic force microscopy (AFM). Films were grown up to 40μm on sapphire with either a GaC1 pretreatment prior to growth or on a ZnO buffer layer. Dislocation densities were found to decrease with increasing film thickness. This is attributed to the mixed nature of the defects present in the film which enabled dislocation annihilation. The thickest film had a defect density of 5×107 dislocations/cm2.

scholarly journals Structural and Stress Properties of AlGaN Epilayers Grown on AlN-Nanopatterned Sapphire Templates by Hydride Vapor Phase Epitaxy

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 704 ◽  
Author(s):  
Chi-Tsung Tasi ◽  
Wei-Kai Wang ◽  
Sin-Liang Ou ◽  
Shih-Yung Huang ◽  
Ray-Hua Horng ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Sapphire Substrate ◽  
Vapor Phase Epitaxy ◽  
Hydride Vapor Phase Epitaxy ◽  
Threading Dislocation ◽  
Force Microscopy ◽  
Al Content ◽  
Atomic Force ◽  
Transmission Electron ◽  
Biaxial Tensile Stress

In this paper, we report the epitaxial growth and material characteristics of AlGaN (Al mole fraction of 10%) on an AlN/nanopatterned sapphire substrate (NPSS) template by hydride vapor phase epitaxy (HVPE). The crystalline quality, surface morphology, microstructure, and stress state of the AlGaN/AlN/NPSS epilayers were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The results indicate that the crystal quality of the AlGaN film could be improved when grown on the AlN/NPSS template. The screw threading dislocation (TD) density was reduced to 1.4 × 109 cm−2 for the AlGaN epilayer grown on the AlN/NPSS template, which was lower than that of the sample grown on a flat c-plane sapphire substrate (6.3 × 109 cm−2). As examined by XRD measurements, the biaxial tensile stress of the AlGaN film was significantly reduced from 1,187 MPa (on AlN/NPSS) to 38.41 MPa (on flat c-plane sapphire). In particular, an increase of the Al content in the overgrown AlGaN layer was confirmed by the TEM observation. This could be due to the relaxation of the in-plane stress through the AlGaN and AlN/NPSS template interface.

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.

High Quality AlN Layer Grown on Patterned Sapphire Substrates by Hydride Vapor-Phase Epitaxy: A Route for Cost Efficient AlN Templates for Deep Ultraviolet Light Devices

2021 ◽  
Vol 21 (9) ◽  
pp. 4881-4885
Author(s):  
Seung-Jae Lee ◽  
Seong-Ran Jeon ◽  
Young Ho Song ◽  
Young-Jun Choi ◽  
Hae-Gon Oh ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Vapor Phase Epitaxy ◽  
Hydride Vapor Phase Epitaxy ◽  
Threading Dislocation ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Order Of Magnitude ◽  
Cost Efficient ◽  
Patterned Sapphire Substrates

We report the characteristics of AlN epilayers grown directly on cylindrical-patterned sapphire substrates (CPSS) by hydride vapor-phase epitaxy (HVPE). To evaluate the effect of CPSS, we analyzed the threading dislocation densities (TDDs) of AlN films grown simultaneously on CPSS and flat sapphire substrate (FSS) by transmission electron microscopy (TEM). The corresponding TDD is measured to be 5.69 x 108 cm−2 for the AlN sample grown on the CPSS that is almost an order of magnitude lower than the value of 3.43 × 109 cm−2 on the FSS. The CPSS contributes to reduce the TDs originated from the AlN/sapphire interface via bending the TDs by lateral growth during the coalescence process. In addition, the reduction of direct interface area between AlN and sapphire by CPSS reduce the generation of TDs.

Bulk Gan Crystal With Low Defect Density Grown By Hydride Vapor Phase Epitaxy

1997 ◽  
Vol 482 ◽  
Author(s):  
A. Usui
Keyword(s):  
Vapor Phase ◽  
Flat Surface ◽  
Defect Density ◽  
Vapor Phase Epitaxy ◽  
Hydride Vapor Phase Epitaxy ◽  
Extended Defect ◽  
New Approach ◽  
Bulk Gan ◽  
Gan Crystal ◽  
Reflectance Measurements

AbstractA new approach to grow thick GaN layers by hydride vapor phase epitaxy (HVPE) is described. Selective growth is carried out at the beginning of growth. The coalescence of selectively grown facet structures makes it possible to achieve a flat surface over the entire substrate. As a result, crack-free GaN films with mirror-like surfaces are successfully grown even to a thickness of about 100 μm on a 2-inch-diameter sapphire substrate. The extended defect density is as low as 6×107 cm−2. The reduction mechanism for dislocation is discussed based on TEM observation. The high optical properties of FIELO GaN are confirmed by 5 K photoluminescence and reflectance measurements.

scholarly journals High carrier mobility in single-crystal PtSe2 grown by molecular beam epitaxy on ZnO(0001)

2D Materials ◽  
2021 ◽  
Author(s):  
Frédéric Bonell ◽  
Alain Marty ◽  
Céline Vergnaud ◽  
Vincent Consonni ◽  
Hanako Okuno ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
High Mobility ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
High Carrier Mobility ◽  
Insulating Substrates

Abstract PtSe2 is attracting considerable attention as a high mobility two-dimensional material with envisioned applications in microelectronics, photodetection and spintronics. The growth of high quality PtSe2 on insulating substrates with wafer-scale uniformity is a prerequisite for electronic transport investigations and practical use in devices. Here, we report the growth of highly oriented few-layers PtSe2 on ZnO(0001) by molecular beam epitaxy. The crystalline structure of the films is characterized with electron and X-ray diffraction, atomic force microscopy and transmission electron microscopy. The comparison with PtSe2 layers grown on graphene, sapphire, mica, SiO2 and Pt(111) shows that among insulating substrates, ZnO(0001) yields films of superior structural quality. Hall measurements performed on epitaxial ZnO/PtSe2 with 5 monolayers of PtSe2 show a clear semiconducting behaviour and a high mobility in excess of 200 cm2V-1s-1 at room temperature and up to 447 cm2V-1s-1 at low temperature.

Structural Characterization of Nc-Si/A-Sio2 Superlattices Subjected To Thermal Treatment

1998 ◽  
Vol 536 ◽  
Author(s):  
G. F. Grom ◽  
L. Tsybeskov ◽  
K. D. Hirschman ◽  
P. M. Fauchet ◽  
J. P. McCaffrey ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Defect Density ◽  
High Temperature Annealing ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Si Nanocrystals

AbstractThe morphology of nanocrystalline (nc)-Si/amorphous (a)-SiO2 superlattices (SLs) is studied using Raman spectroscopy in the acoustic and optical phonon ranges, transmission electron microscopy (TEM), and atomic force microscopy (AFM). It is demonstrated that high temperature annealing (up to 1100°C) and oxidation in O2/H2O ambient do not destroy the SL structure, which retains its original periodicity and nc-Si/a-SiO2 interface abruptness. It is found that oxidation at high temperatures reduces the defect density in nc-Si/a-SiO2 SLs and induces the lateral coalescence of Si nanocrystals (NCs). The size, shape, packing density, and crystallographic orientation of the Si nanocrystals are studied as a function of the oxidation time.

Studies towards freestanding GaN in hydride vapor phase epitaxy by in-situ etching of a sacrificial ZnO buffer layer

2009 ◽  
Vol 6 (S2) ◽  
pp. S352-S355 ◽  
Author(s):  
Frank Lipskil ◽  
Sarad B. Thapa ◽  
Joachim Hertkorn ◽  
Thomas Wunderer ◽  
Stephan Schwaiger ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Vapor Phase ◽  
Vapor Phase Epitaxy ◽  
Hydride Vapor Phase Epitaxy ◽  
Zno Buffer Layer
Sign in / Sign up

Export Citation Format

Share Document