KINETICS, MICROSTRUCTURE AND STRAIN IN GaN THIN FILMS GROWN VIA PENDEO-EPITAXY

2004 ◽  
Vol 14 (01) ◽  
pp. 21-37
Author(s):  
A. M. ROSKOWSKI ◽  
E. A. PREBLE ◽  
S. EINFELDT ◽  
P. M. MIRAGLIA ◽  
J. SCHUCK ◽  
...  

Maskless pendeo-epitaxy involves the lateral and vertical growth of cantilevered "wings" of material from the sidewalls of unmasked etched forms. Gallium Nitride films grown at 1020°C via metalorganic vapor phase epitaxy on GaN / AlN /6 H - SiC (0001) substrates previously etched to form [Formula: see text]-oriented stripes exhibited similar vertical [0001] and lateral [Formula: see text] growth rates, as shown by cross-sectional scanning electron microscopy. Increasing the temperature increased the growth rate in the latter direction due to the higher thermal stability of the [Formula: see text] surface. The [Formula: see text] surface was atomically smooth under all growth conditions with a root mean square (RMS)=0.17 nm. High resolution X-ray diffraction and atomic force microscopy of the pendeo-epitaxial films confirmed transmission electron microscopy results regarding the significant reduction in dislocation density in the wings. This result is important for the properties of both optoelectronic and microelectronic devices fabricated in III-Nitride structures. Measurement of strain indicated that the wing material is crystallographically relaxed as evidenced by the increase in the c-axis lattice parameter and the upward shift of the E2 Raman line frequency. A strong D°X peak at 3.466 eV was also measured in the wing material. However, tilting of the wings of ≤0.15° occurred due to the tensile stresses in the stripes induced by the mismatch in the coefficients of thermal expansion between the GaN and the underlying substrate.

2020 ◽  
Vol MA2020-02 (24) ◽  
pp. 1750-1750
Author(s):  
Andrea Quintero Colmenares ◽  
Patrice Gergaud ◽  
Jean-Michel Hartmann ◽  
Vincent Delaye ◽  
Nicolas Bernier ◽  
...  

2020 ◽  
Vol 1004 ◽  
pp. 414-420
Author(s):  
Junro Takahashi ◽  
Kotaro Kawaguchi ◽  
Kazuhiko Kusunoki ◽  
Tomoyuki Ueyama ◽  
Kazuhito Kamei

We have studied the microstructure of the growth surface of the 4H-SiC grown by the m-face solution growth. Atomic Force Microscopy (AFM) revealed the micro-striped morphology with the asperity of several nm in the band-like morphology region. The cross-sectional Transmission Electron Microscopy (XTEM) showed that the growth surface consisted of a bunch of nanofacets and vicinal surface. This peculiar morphology is totally different from that of conventional spiral growth on c-face, which can be closely related with the growth mechanism of the m-face solution growth.


2008 ◽  
Vol 381-382 ◽  
pp. 525-528 ◽  
Author(s):  
B.L. Wang ◽  
Han Huang ◽  
Jin Zou ◽  
Li Bo Zhou

Silicon (100) substrates machined by chemo-mechanical-grinding (CMG) and chemicalmechanical- polishing (CMP) were investigated using atomic force microscopy, cross-sectional transmission electron microscopy and nanoindentation. It was found that the substrate surface after CMG was slightly better than machined by CMP in terms of roughness. The transmission electron microscopy analysis showed that the CMG-generated subsurface was defect-free, but the CMP specimen had a crystalline layer of about 4 nm in thickness on the top of the silicon lattice as evidenced by the extra diffraction spots. Nanoindentation results indicated that there exists a slight difference in mechanical properties between the CMG and CMP machined substrates.


1998 ◽  
Vol 535 ◽  
Author(s):  
P. Kopperschmidt ◽  
S T. Senz ◽  
R. Scholz ◽  
G. Kästner ◽  
U. Gösele ◽  
...  

AbstractWe realized “compliant” substrates in the square centimeter range by twist-wafer bonding of an (100) GaAs handle wafer to another (100) GaAs wafer with a several nm thick epitaxially grown GaAs layer followed by an appropriate back-etch procedure. The twist angle between the two GaAs wafers was chosen between 4 and 15 degrees. The twisted layers were characterized by area scanned X-ray diffraction, optical and electron microscopy and atomic force microscopy. Occasionally we observed regions showing pinholes in the transferred thin twistbonded GaAs layer.After epitaxial deposition of 300 nm InP and InGaAs films with different degrees of mismatch on these substrates, transmission electron microscopy revealed grains which are epitaxially oriented to either the substrate or the twist-bonded layer. The grain boundaries between the twisted and untwisted grains probably collect threading dislocations, thus reducing their density in the areas free of boundaries.


2015 ◽  
Vol 821-823 ◽  
pp. 213-216
Author(s):  
S.M. Ryndya ◽  
N.I. Kargin ◽  
A.S. Gusev ◽  
E.P. Pavlova

Silicon carbide thin films were obtained on Si (100) and (111) substrates by means of vacuum laser ablation of α-SiC ceramic target. The influence of substrate temperature on composition, structure and surface morphology of experimental samples was examined using Rutherford backscattering spectrometry (RBS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), conventional and high-resolution transmission electron microscopy (TEM/HRTEM), atomic force microscopy (AFM), selected area electron diffraction (SAED) and X-ray diffraction (XRD) methods.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Angela De Bonis ◽  
Agostino Galasso ◽  
Antonio Santagata ◽  
Roberto Teghil

A MgB2target has been ablated by Nd:glass laser with a pulse duration of 250 fs. The plasma produced by the laser-target interaction, showing two temporal separated emissions, has been characterized by time and space resolved optical emission spectroscopy and ICCD fast imaging. The films, deposited on silicon substrates and formed by the coalescence of particles with nanometric size, have been analyzed by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, micro-Raman spectroscopy, and X-ray diffraction. The first steps of the films growth have been studied by Transmission Electron Microscopy. The films deposition has been studied by varying the substrate temperature from 25 to 500°C and the best results have been obtained at room temperature.


1995 ◽  
Vol 399 ◽  
Author(s):  
H. Lafontaine ◽  
D.C. Houghton ◽  
B. Bahierathan ◽  
D.D. Perovic ◽  
J.-M. Baribeau

ABSTRACTSeveral Si1-xGex/Si heterostructures were grown at 525°C using a commercially available UHV-CVD reactor. Layers with a germanium fraction ranging from 0.15 to 0.5 were examined by means of cross-sectional transmission electron microscopy and atomic force microscopy. Surface waves were found in layers with a thickness above a critical value which decreases rapidly as the Ge fraction is increased. Both experimental and modeling results show that surface waves are generated before misfit dislocations for Ge fractions above 0.3.


Author(s):  
S. S. Srinivasan ◽  
N. Kislov ◽  
Yu. Emirov ◽  
D. Y. Goswami ◽  
E. K. Stefanakos

Nanoparticles of Zinc Ferrite (ZnFe2O4) prepared by both wet- and dry- high-energy ball milling (HEBM), have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), surface area and pore size distribution (BET) and wavelength-dependent diffuse reflectance and scattering turned into absorption coefficient estimation using the Kubelka-Munk theory. It was found that after 72 hours of HEBM, the particle size was decreased from 220 nm for the initial material to 16.5 nm and 9.4 nm for the wet- and dry-milled samples, respectively. The optical absorption analysis revealed that the energy gap is increased (blue shift) by 0.45 eV for wet-milled and decreased (“anomalous” red shift) by 0.15 eV for dry-milled samples of ZnFe2O4 as the particle size decreased.


2019 ◽  
Vol 29 (4) ◽  
pp. 67
Author(s):  
Barakat A. F. Kamel

In this research work, the nanoparticles of aluminum oxide were synthesized by two ways. The first way is the biological by using (Pseudomonas aeruginosa) bacteria with a rate diameter (102.35) nm. The second way is the electrochemical with a rate diameter (62) nm. These nanoparticles were characterized by Atomic Force Microscopy (AFM), X-Ray diffraction technique (XRD), Transmission Electron Microscopy (TEM) and Scanninig Electron Microscopy (SEM). Alumina nanoparticles are thermodynamically stable particles over a wide temperature range . The biological activity of these nanoparticles toward different species of pathogenic bacteria (Staphylococcus aureus ) and (Pseudo monas) has been investigated. The results stated that the nanoparticles prepared by chemical way was more effective on the inhibition of bacteria than the nanoparticles prepared by biological way


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