scholarly journals Comparaciones ópticas y estructurales de las películas de Óxido de Silicio rico en Silicio (SRO) depositadas por las técnicas LPCVD y HFCVD

2019 ◽  
pp. 19-25
Author(s):  
Haydee Patricia Martínez Hernández ◽  
José Alberto Luna-López ◽  
Adán Luna-Flores ◽  
José Álvaro David Hernández-De la Luz
Keyword(s):  
Electron Microscopy ◽  
Silicon Nanocrystals ◽  
Chemical Vapor ◽  
Band Gap Energy ◽  
Thermal Treatments ◽  
Electroluminescent Devices ◽  
Transmission Electron ◽  
Hot Filament ◽  
Structural Characterizations ◽  
Deposition Techniques

In this work, we conducted a comparative study of the optical and structural properties of Silicon Rich Oxide (SRO) films deposited by two chemical vapor deposition techniques: at Low Pressure (LPCVD) and activated by Hot Filament (HFCVD). SRO-LPCVD films were deposited at a silane and nitrous oxide pressures (R_0=P_(N_2 O)/P_(〖SiH〗_4 )) rate of R0=10 y R0=25. SRO-HFCVD films were deposited at a hydrogen pressure of 25 and 100 sccm, at a distance between source and substrate of 8 mm. To improve the optical properties, we have subjected the films obtained by both techniques to thermal treatments at high temperatures. The optical and structural characterizations that we used for comparison of the films were: Null Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR) and Photoluminescence (FL), Scanning Electron Microscopy (SEM) and High-Resolution Transmission Electron Microscopy (HRTEM). The SEM microscopy corroborates the thicknesses of the SRO films obtained by Null Spectroscopy, likewise, the HRTEM microscopy corroborates the diameter size of the silicon nanocrystals (ncs-Si), which also were calculated theoretically with the band gap energy (Eg) obtained in the FL spectra. These characterizations show that either of the two techniques are excellent alternatives for obtaining SRO films with photoluminescent emission, which can be used for photodetector and electroluminescent devices.

Synthesis of Crystalline C3N4 films and the new C-N Phases

1996 ◽  
Vol 441 ◽  
Author(s):  
Yan Chen ◽  
D. J. Johnson ◽  
R. H. Prince ◽  
Liping Guo ◽  
E. G. Wang
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Growth Parameters ◽  
Chemical Vapor ◽  
Monoclinic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Transmission Electron ◽  
Hot Filament

AbstractCrystalline C-N films composed of α- and β-C3N4, as well as other C-N phases, have been synthesized via bias-assisted hot-filament chemical vapor deposition using a gas mixture of nitrogen and methane. Scanning electron microscopy(SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the films. Lattice constants of the α- and β-C3N4 phases obtained coincide very well with the theoretical values. In addition to these phases, two new C-N phases in the films have been identified by TEM and XRD; one having a tetragonal structure with a = 5.65 Å, c = 2.75Å, and the second having a monoclinic structure with a = 5.065 Å, b= 11.5 Å, c = 2.801 Å and β = 96°. Their stoichiometric values and atomic arrangements have not yet been identified. Furthermore, variation in growth parameters, for example methane concentration, bias voltage, etc., can yield preferred growth of different C-N phases.

scholarly journals Study of the Thermal Annealing on Structural and Morphological Properties of High-Porosity A-WO3 Films Synthesized by HFCVD

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1298 ◽  
Author(s):  
M. Cruz-Leal ◽  
O. Goiz ◽  
F. Chávez ◽  
G. F. Pérez-Sánchez ◽  
N. Hernández-Como ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Annealing ◽  
Chemical Vapor ◽  
Morphological Properties ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Vapor Deposition Technique ◽  
Hot Filament

High-porosity nanostructured amorphous tungsten OXIDE (a-WO3) films were synthesized by a Hot Filament Chemical Vapor Deposition technique (HFCVD) and then transformed into a crystalline WO3 by simple thermal annealing. The a-WO3 films were annealed at 100, 300, and 500 °C for 10 min in an air environment. The films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-Raman spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and UV–vis spectroscopy. Results revealed that the a-WO3 films were highly porous, composed of cauliflower-like structures made of nanoparticles with average sizes of 12 nm. It was shown that the effect of annealing on the morphology of the a-WO3 films leads to a sintering process. However, the morphology is conserved. It was found that at annealing temperatures of 100 °C, the a-WO3 films are of an amorphous nature, while at 300 °C, the films crystallize in the monoclinic phase of WO3. The calculated bandgap for the a-WO3 was 3.09 eV, and 2.53 eV for the film annealed at 500 °C. Finally, the results show that porous WO3 films preserve the morphology and maintain the porosity, even after the annealing at 500 °C.

Structural Characterization of Crystalline Si-C-N Films

1997 ◽  
Vol 498 ◽  
Author(s):  
E. G. Wang ◽  
Cheng-Zhang Wang ◽  
Changfeng Chen ◽  
Yan Chen
Keyword(s):  
Electron Microscopy ◽  
Structural Characterization ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Hot Filament ◽  
Microscopy Images ◽  
Insight Into

ABSTRACTHigh quality crystalline Si-C-N films on silicon substrate have been synthesized by bias-assisted hot filament chemical vapor deposition (CVD) using a gas mixture of nitrogen and methane. Scanning electron microscopy images show that the Si-C-N clusters are composed of many columnar crystals with hexagonal facets. X-ray diffraction and transmission electron microscopy analyses confirm the formation of Si-C-N crystals with lattice parameters a=7.06Å and c=2.72Å. First principles calculations are performed for β-Si3–nCnN4 (n=0,1,2,3). The calculated results support the experimental structural characterization and provide further insight into the property of the system. With increasing amount of C substitution, the bulk modulus progressively increases to 4.44 Mbar, comparable to that of diamond (4.43 Mbar), and both a and c are reduced but the ratio c/a shows little variation.

Heteroepitaxial Diamond Formed on Silicon Wafer Observed by High Resolution Electron Microscopy

1994 ◽  
Vol 357 ◽  
Author(s):  
Jie Yang ◽  
Zhangda Lin ◽  
Li-Xin Wang ◽  
Sing Jin ◽  
Ze Zhang
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Diamond Films ◽  
Chemical Vapor ◽  
High Resolution Electron Microscopy ◽  
Cross Sectional ◽  
Diamond Crystals ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Hot Filament

AbstractDiamond films with high preferential orientation (111) on silicon (100) crystalline orientation substrates had been obtained by hot-filament chemical vapor deposition (HFCVD) method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and high-resolution cross-sectional transmission electron microscopy (HREM) are used to characterizate the structure and morphology of the synthesised diamond films. Diamond (111) plans had been local grown epitaxially on the Si(100) substrate observed by HREM. SEM photographes show that plane diamond crystals have been obtained.

SYNTHESIS OF HIGH QUALITY CRYSTALLINE C-N FILMS ON SILICON

1996 ◽  
Vol 10 (12) ◽  
pp. 567-571 ◽  
Author(s):  
YAN CHEN ◽  
E.G. WANG ◽  
FENG CHEN ◽  
LIPING GUO
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Interfacial Layer ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Transmission Electron ◽  
Hot Filament ◽  
Microscopy Images

High quality crystalline C–N films have been synthesized via hot filament chemical vapor deposition using a gas mixture of nitrogen and methane. Scanning electron microscopy images show that a high density of crystalline clusters has been achieved. The clusters are composed of small columnar crystals (20–200 nm across) with hexagonal facets. Energy dispersive X ray analysis indicates a relative nitrogen:carbon composition of 1.30–2.5. X ray diffraction results indicate the films composed of β- and α- C 3 N 4 phases. Together with transmission electron microscopy analyses, we suggest that an interfacial layer C 3−x Si x N 4 is formed between the silicon substrate and the crystalline carbonnitride films.

Electron Microscopy Studies on the Growth of Well-Aligned NiSi/SiC Core-Shell Nanowires Synthesized by HWCVD

2017 ◽  
Vol 264 ◽  
pp. 21-24
Author(s):  
Najwa binti Hamzan ◽  
Muhammad Firdaus Omar ◽  
Huang Nay Ming ◽  
Boon Tong Goh
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor ◽  
Core Shell ◽  
Transmission Electron ◽  
Hot Wires ◽  
P Type ◽  
Hot Filament ◽  
Amorphous Sic ◽  
Type Crystal ◽  
Shell Nanowires

Well-aligned NiSi/SiC core-shell nanowires were grown on Ni-coated p-type crystal Si (100) substrates by using hot-wires chemical vapor deposition (HWCVD) technique. The growth of the nanowires was performed at a substrate temperature of 450°C and facilitated by a hot-filament at a temperature above 1800°C. Electron microscopy characterizations were employed to investigate the morphology, and microstructure properties of the nanowires. A high-resolution transmission electron microscopy (TEM) images indicate that the nanowires were structured by single crystalline NiSi and amorphous SiC as the core and shell respectively. Moreover, the TEM images showed presence of 3C-SiC nano-crystallites embedded within an amorphous matrix in the shell.

Microstructures of SiC and Si3N4 with fibrous inclusions

1986 ◽  
Vol 44 ◽  
pp. 492-493
Author(s):  
N. J. Tighe ◽  
J. Sun ◽  
R.-M. Hu
Keyword(s):  
Vapor Deposition ◽  
Chemical Vapor ◽  
Crack Deflection ◽  
Fiber Bundles ◽  
High Temperature Strength ◽  
Graphite Fiber ◽  
Triple Junctions ◽  
Transmission Electron ◽  
Compact Graphite ◽  
Deposition Techniques

Particles of BN,and C are added in amounts of 1 to 40% to SiC and Si3N4 ceramics in order to improve their mechanical properties. The ceramics are then processed by sintering, hot-pressing and chemical vapor deposition techniques to produce dense products. Crack deflection at the particles can increase toughness. However the high temperature strength and toughness are determined byphase interactions in the environmental conditions used for testing. Examination of the ceramics by transmission electron microscopy has shown that the carbon and boron nitride particles have a fibrous texture. In the sintered aSiC ceramic the carbon appears as graphite fiber bundles in the triple junctions and as compact graphite particles within some grains. Examples of these inclusions are shown in Fig. 1A and B.

Transmission Electron Microscopy (TEM) Specimen Preparation Technique using Focused Ion Beam (FIB): Application to Material Characterization of Chemical Vapor Deposition of Tungsten (W) and Tungsten Silicides (WSix)

1997 ◽  
Author(s):  
K. Doong ◽  
J.-M. Fu ◽  
Y.-C. Huang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Transmission Electron

Abstract The specimen preparation technique using focused ion beam (FIB) to generate cross-sectional transmission electron microscopy (XTEM) samples of chemical vapor deposition (CVD) of Tungsten-plug (W-plug) and Tungsten Silicides (WSix) was studied. Using the combination method including two axes tilting[l], gas enhanced focused ion beam milling[2] and sacrificial metal coating on both sides of electron transmission membrane[3], it was possible to prepare a sample with minimal thickness (less than 1000 A) to get high spatial resolution in TEM observation. Based on this novel thinning technique, some applications such as XTEM observation of W-plug with different aspect ratio (I - 6), and the grain structure of CVD W-plug and CVD WSix were done. Also the problems and artifacts of XTEM sample preparation of high Z-factor material such as CVD W-plug and CVD WSix were given and the ways to avoid or minimize them were suggested.

Low Temperature Large Scale CVD Synthesis of Nano Onion-Like Fullerenes

2012 ◽  
Vol 490-495 ◽  
pp. 3211-3214 ◽  
Author(s):  
Lei Shan Chen ◽  
Cun Jing Wang
Keyword(s):  
Electron Microscopy ◽  
Low Temperature ◽  
Aluminum Hydroxide ◽  
Large Scale ◽  
Iron Catalyst ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Naoh Solution ◽  
Synthesis Reactions

Synthesis reactions were carried out by chemical vapor deposition using iron catalyst supported on aluminum hydroxide at 400 °C and 420 °C, in the presence of argon as carrier gas and acetylene as carbon source. The aluminum hydroxide support was separated by refluxing the samples in 40% NaOH solution for 2 h and 36% HCl solution for 24 h, respectively. The samples were characterized by field-emission scanning electron microscopy, energy dispersive spectroscopy, high-resolution transmission electron microscopy and X-ray diffraction. The results show that carbon nanotubes were the main products at 420 °C, while large scale high purity nano onion-like fullerenes encapsulating Fe3C, with almost uniform sizes ranging from 10-50 nm, were obtained at the low temperature of 400 °C.

Sign in / Sign up

Export Citation Format

Share Document