Influence of Thermal Treatments on the Chemistry and Self-Assembly of Ge Nanoparticles on SiO2 Surfaces

2004 ◽  
Vol 830 ◽  
Author(s):  
Scott K. Stanley ◽  
Shawn S. Coffee ◽  
John G. Ekerdt
Keyword(s):  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Chemical Vapor ◽  
Thermal Treatments ◽  
X Ray ◽  
Agglomeration Process ◽  
Oxide Substrate ◽  
Temperature Programmed ◽  
Hot Filament ◽  
Substrate Temperatures

ABSTRACTGeH4 is thermally cracked over a hot filament depositing 0.7–15 ML Ge onto 2–7 nm SiO2/Si(100) at substrate temperatures of 300–970 K. Ge, GeHx, GeO, and GeO2 desorption is monitored through temperature programmed desorption in the temperature range 300–1000 K. Ge bonding changes are analyzed during annealing from 300–1000 K with X-ray photoelectron spectroscopy (XPS). Low temperature desorption features are attributed to GeO and GeH4. No GeO2 desorption is observed, but GeO2 decomposition to Ge through high temperature pathways is seen above 700 K. Germanium oxidization results from Ge etching of the oxide substrate, which is demonstrated through XPS. Ge nanoparticle formation on SiO2 is demonstrated using the agglomeration process. With these results, explanations for the difficulties of conventional chemical vapor deposition to produce Ge nanocrystals on SiO2 surfaces are proposed.

Interactions of Ge Atoms with High- ê Oxide Dielectric Surfaces

2005 ◽  
Vol 879 ◽  
Author(s):  
Scott K. Stanley ◽  
John G. Ekerdt
Keyword(s):  
Oxide Layer ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Temperature Programmed Desorption ◽  
Tungsten Filament ◽  
X Ray ◽  
Dielectric Surfaces ◽  
Temperature Programmed ◽  
The Stability ◽  
Ge Nanocrystals

AbstractGe is deposited on HfO2 surfaces by chemical vapor deposition (CVD) with GeH4. 0.7-1.0 ML GeHx (x = 0-3) is deposited by thermally cracking GeH4 on a hot tungsten filament. Ge oxidation and bonding are studied at 300-1000 K with X-ray photoelectron spectroscopy (XPS). Ge, GeH, GeO, and GeO2 desorption are measured with temperature programmed desorption (TPD) at 400-1000 K. Ge initially reacts with the dielectric forming an oxide layer followed by Ge deposition and formation of nanocrystals in CVD at 870 K. 0.7-1.0 ML GeHx deposited by cracking rapidly forms a contacting oxide layer on HfO2 that is stable from 300-800 K. Ge is fully removed from the HfO2 surface after annealing to 1000 K. These results help explain the stability of Ge nanocrystals in contact with HfO2.

A STUDY OF ALUMINA THIN FILMS GROWN BY LOW PRESSURE MOCVD: XPS AND AES

2002 ◽  
Vol 16 (08) ◽  
pp. 1261-1267 ◽  
Author(s):  
M. P. SINGH ◽  
S. A. SHIVASHANKAR ◽  
T. SHRIPATHI
Keyword(s):  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
Alumina Film ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron ◽  
Low Pressure Mocvd ◽  
Substrate Temperatures

We have studied the chemical composition of alumina ( Al 2 O 3) films grown on Si(100) at different substrate temperatures by metalorganic chemical vapor deposition (MOCVD) using aluminium acetylactonate { Al(acac) 3} as the precursor. We have found that the resulting films of Al 2 O 3 contain substantial amounts of carbon. X-ray photoelectron spectroscopy (XPS) was employed to study the chemical state of carbon present in such films. The XPS spectrum reveals that the carbon present in Al 2 O 3 film is graphitic in nature. Auger electron spectroscopy (AES) was employed to study the distribution of carbon in the Al 2 O 3 films. The AES depth profile reveals that carbon is present throughout the film. The AES study on Al 2 O 3 films corroborates the XPS findings. An investigation of the Al 2 O 3/ Si (100) interface was carried out using cross-sectional transmission electron microscopy (XTEM). The TEM study reveals textured growth of alumina film on Si(100), with very fine grains of alumina embedded in an amorphous carbon-containing matrix.

Deposition and Properties of AlN Films Prepared by Low Pressure CVD with a Metalorganic Precursor

1993 ◽  
Vol 335 ◽  
Author(s):  
M. J. Cook ◽  
P. K. Wu ◽  
N. Patibandla ◽  
W. B. Hillig ◽  
J. B. Hudson
Keyword(s):  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Low Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fiber Coating ◽  
Pressure Chemical ◽  
Substrate Temperatures ◽  
Carbon Concentrations

AbstractAluminum nitride films were deposited on Si (100) and sapphire (1102) substrates by low pressure chemical vapor deposition using the metalorganic precursor trisdimethylaluminum amide, [(CH3)2AlNH2]3. Depositions were carried out in a cold wall reactor with substrate temperatures between 500 and 700 °C and precursor temperatures between 50 and 80 °C. The films were analyzed by X-ray photoelectron spectroscopy, X-ray diffraction, optical microscopy and scanning electron microscopy. The films were generally smooth and adherent with colors ranging from transparent to opaque grey. Cracking and spallation were seen to occur at high film thickness. Deposition rates ranged from 20 to 300 Å/min and increased with both precursor and substrate temperature. Carbon concentrations were small, < 5 at. %, while oxygen concentrations were higher and showed a characteristic profile versus depth in the film. High temperature compatibility testing with sapphire/AlN/MoSi2 samples was carried out to determine film effectiveness as a fiber coating in a composite.

Synthesis and characterization of B–C–N compounds on molybdenum

1999 ◽  
Vol 14 (3) ◽  
pp. 1137-1141 ◽  
Author(s):  
Jie Yu ◽  
E. G. Wang ◽  
Guichang Xu
Keyword(s):  
Substrate Temperature ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Synthesis And Characterization ◽  
Boron Carbonitride ◽  
X Ray ◽  
Hot Filament ◽  
N Compounds

B–C–N compounds were prepared on molybdenum by means of bias-assisted hot filament chemical vapor deposition (HFCVD). Effect of the substrate temperature (Ts) on the growth of B–C–N films has been investigated systematically by x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) based on the detailed analysis and calculation of the XPS. The substrate temperature plays a key role in the formation of the bonding states, the composition, and the surface morphology. Boron carbonitride is the main phase at all depositing temperatures, and the obtained compounds are as follows: B0.83C0.17 + B0.39C0.35N0.26 at 873 K, B0.30C0.34N0.36 at 973 K, B0.64C0.36 + B0.51C0.23N0.26 at 1073 K, B0.51C0.31N0.18 at 1173 K, and B0.37C0.54N0.09 at 1273 K.

Nanocrystalline Silicon Carbide Film Growth Using Hot Filament CVD

1999 ◽  
Vol 593 ◽  
Author(s):  
M.B. Yu ◽  
Rusli S.F. ◽  
Yoon J. ◽  
Cui K. Chew ◽  
J. Ahn ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Photoelectron Spectroscopy ◽  
Film Growth ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Transverse Optical ◽  
Diffraction Spectrum ◽  
Optical Phonons ◽  
X Ray ◽  
Hot Filament

ABSTRACTNanocrystalline cubic silicon carbide (nc-SiC) films embedded in an amorphous SiC matrix was fabricated by the hot filament chemical vapor deposition (HFCVD) technique using methane and silane as reactance gases. The presence of nanocrystalline grains was confirmed by the high resolution transmission electron microscope (HRTEM). x-ray photoelectron spectroscopy (XPS) measurements showed that the atomic percentages of Si and C are nearly 50%. X-ray diffraction spectrum of the sample revealed a diffraction peak of 3C-SiC (111) at 2ϕ=35.6°. Infrared absorption of the film had a strong peak at 800 cm−1 which is related to the transverse optical phonons of Si-C bonds in 3C-SiC. Raman spectrum of the sample showed that there are two peaks at 790 cm−l and 970 cm−1 which correspond to longitudinal and transverse optical phonons of SiC respectively. Room temperature photoluminescence (PL) study of these nc-SiC samples revealed a visible peak at 2.2 eV, which has not been observed so far for 3C-SiC.

scholarly journals Graphene Growth Directly on SiO2/Si by Hot Filament Chemical Vapor Deposition

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 109
Author(s):  
Sandra Rodríguez-Villanueva ◽  
Frank Mendoza ◽  
Alvaro A. Instan ◽  
Ram S. Katiyar ◽  
Brad R. Weiner ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Si Substrate ◽  
Copper Strip ◽  
X Ray ◽  
Catalytic Material ◽  
Hot Filament

We report the first direct synthesis of graphene on SiO2/Si by hot-filament chemical vapor deposition. Graphene deposition was conducted at low pressures (35 Torr) with a mixture of methane/hydrogen and a substrate temperature of 970 °C followed by spontaneous cooling to room temperature. A thin copper-strip was deposited in the middle of the SiO2/Si substrate as catalytic material. Raman spectroscopy mapping and atomic force microscopy measurements indicate the growth of few-layers of graphene over the entire SiO2/Si substrate, far beyond the thin copper-strip, while X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy showed negligible amounts of copper next to the initially deposited strip. The scale of the graphene nanocrystal was estimated by Raman spectroscopy and scanning electron microscopy.

Synthesizing Nanocrystalline Carbon Thin Films by Hot Filament Chemical Vapor Deposition and Controlling Their Microstructure

2002 ◽  
Vol 17 (7) ◽  
pp. 1820-1833 ◽  
Author(s):  
S. Gupta ◽  
B. R. Weiner ◽  
G. Morell
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Noble Gas ◽  
Ion Beam ◽  
Chemical Vapor ◽  
X Ray ◽  
Hot Filament ◽  
Methane Concentrations

Nanocrystalline carbon (n-C) thin films were deposited on Mo substrates using methane (CH4) and hydrogen (H2) by the hot-filament chemical vapor deposition (HFCVD) technique. Process parameters relevant to the secondary nucleation rate were systematically varied (0.3–2.0% methane concentrations, 700–900 °C deposition temperatures, and continuous forward and reverse bias during growth) to study the corresponding variations in film microstructure. Standard nondestructive complementary characterization tools such as scanning electron microscopy, x-ray diffraction, atomic force microscopy, Raman spectroscopy, and x-ray photoelectron spectroscopy were utilized to obtain a coherent and comprehensive picture of the microstructure of these films. Through these studies we obtained an integral picture of the material grown and learned how to control key material properties such as surface morphology (faceted versus evenly smooth), grain size (microcrystalline versus nanocrystalline), surface roughness (from rough 150 rms to smooth 70 rms), and bonding configuration (sp3 C versus sp2 C), which result in physical properties relevant for several technological applications. These findings also indicate that there exist fundamental differences between HFCVD and microwave CVD (MWCVD) for methane concentrations above 1%, whereas some similarities are drawn among films grown by ion-beam assisted deposition, HFCVD assisted by low-energy particle bombardment, and MWCVD using noble gas in replacement of traditionally used hydrogen.

Hot Filament Assisted CVD of Titanium Nitride Films

1993 ◽  
Vol 327 ◽  
Author(s):  
Sadanand V. Deshpande ◽  
Erdogan Gulari
Keyword(s):  
Thin Films ◽  
Titanium Nitride ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Titanium Chloride ◽  
X Ray ◽  
Aluminum Metallization ◽  
Temperature Deposition ◽  
Hot Filament

AbstractTitanium nitride thin films have been deposited using a novel Hot Filament Chemical Vapor Deposition (HFCVD) technique. In this technique, a resistively heated tungsten wire (∼1700°C) is used to decompose ammonia to obtain highly reactive nitrogen precursor species. This approach allows for low temperature deposition of nitride thin films. In the past, we have used this method to deposit good quality silicon and aluminum nitride films. Titanium nitride thin films have been deposited on Si(100) at substrate temperatures from 500°C to 600°C. These films were characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction, Rutherford backscattering spectroscopy (RBS) and scanning electron microscopy. The effects of deposition pressure, substrate temperature and titanium chloride flow rate on film properties have been studied. TiN films with resistivities as low as 80.0 μΩ-cm have been deposited. RBS analysis indicates that the films serve as excellent diffusion barriers for copper and aluminum metallization on silicon.

scholarly journals Oxidative chemical vapor deposition of polyaniline thin films

2017 ◽  
Vol 8 ◽  
pp. 1266-1276 ◽  
Author(s):  
Yuriy Y Smolin ◽  
Masoud Soroush ◽  
Kenneth K S Lau
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Pani Film ◽  
Antimony Pentachloride ◽  
X Ray ◽  
Substrate Temperatures ◽  
Deposited Film ◽  
Reactor Pressure

Polyaniline (PANI) is synthesized via oxidative chemical vapor deposition (oCVD) using aniline as monomer and antimony pentachloride as oxidant. Microscopy and spectroscopy indicate that oCVD processing conditions influence the PANI film chemistry, oxidation, and doping level. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) indicate that a substrate temperature of 90 °C is needed to minimize the formation of oligomers during polymerization. Lower substrate temperatures, such as 25 °C, lead to a film that mostly includes oligomers. Increasing the oxidant flowrate to nearly match the monomer flowrate favors the deposition of PANI in the emeraldine state, and varying the oxidant flowrate can directly influence the oxidation state of PANI. Changing the reactor pressure from 700 to 35 mTorr does not have a significant effect on the deposited film chemistry, indicating that the oCVD PANI process is not concentration dependent. This work shows that oCVD can be used for depositing PANI and for effectively controlling the chemical state of PANI.

Sign in / Sign up

Export Citation Format

Share Document