Laser-Assisted Deposition of Fe and W: Photodecomposition of Fe(CO)5, and W(CO)6 on Si(111)-(7×7)

1987 ◽  
Vol 101 ◽  
Author(s):  
Jon R. Swanson ◽  
C.M. Friend ◽  
Y.J. Chabal
Keyword(s):  
Vapor Deposition ◽  
Electronic Excitation ◽  
Chemical Vapor ◽  
Temperature Programmed Desorption ◽  
Observable Effect ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Temperature Programmed ◽  
Molecular Desorption ◽  
Initial Results

ABSTRACTThe laser-assisted chemical vapor deposition (LCVD) of Fe and W on Si(lll)-(7×7) was investigated under ultrahigh vacuum conditions at 120 K. Multiple internal reflection Fourier transform infrared and Auger electron spectroscopies and temperature programmed desorption and low energy electron diffraction were used to study the adsorption and decomposition of Fe(C0)5 and w(C0)6 on the surface. Neither of the molecules thermally reacts in temperature programmed desorption experiments. Reversible molecular desorption is exclusively observed. Decomposition of both molecules via electronic excitation was induced by ultraviolet, but not visible photons. This was shown by measuring the photodecomposition yield as a function of wavelength. Visible photolysis (λ=720 nm) had no observable effect on either molecule. No surface stable, partially decarbonylated, Fe(C0), x<5, fragments observable with infrared spectroscopy were produced by photolysis. Also, no new features were observed in temperature programmed desorption experiments and only iron was detected on the surface after photolysis. In contrast, initial results indicate that photolysis of W(C0)fi does produce surface stable, W(C0), x<6, fragments.

Heteroepitaxial System of h-BN/Monolayer Graphene on Ni(111)

2003 ◽  
Vol 10 (04) ◽  
pp. 697-703 ◽  
Author(s):  
T. Tanaka ◽  
A. Itoh ◽  
K. Yamashita ◽  
E. Rokuta ◽  
C. Oshima
Keyword(s):  
Vapor Deposition ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Elevated Temperatures ◽  
Chemical Vapor ◽  
Low Energy ◽  
Monolayer Graphene ◽  
Low Energy Electron Diffraction ◽  
Ni Substrate ◽  
Low Energy Electron

A heteroepitaxial system of h-BN/monolayer graphene on Ni(111) has been investigated by means of vibrational spectroscopy, accompanied by low energy electron diffraction (LEED) and Auger electron spectroscopy (AES). The system was prepared in an epitaxial manner on a Ni(111) surface by chemical vapor deposition (CVD). We found that phonon peaks in observed spectra showed typical features of Fuchs–Kliewer (FK) phonons. The vibrational spectra of h-BN films ranging in thickness from 0 to 8.7 monolayers have been compared with theoretical spectra based on a dielectric theory. Detailed analysis has revealed new types of phonons, of which the vibrational amplitudes are localized at edges of h-BN nanocrystals. In addition, we have observed subsidence phenomena of the graphene and h-BN layers into Ni substrate at elevated temperatures.

The Interaction of HCl With polycrystalline β-SiC: Evidence for a Site-Blocking Mechanism for HCl Inhibition of SiC CVD

1995 ◽  
Vol 410 ◽  
Author(s):  
Michelle T. Schulberg ◽  
Mark D. Allendorf ◽  
Duane A. Outka
Keyword(s):  
Vapor Deposition ◽  
Electron Spectroscopy ◽  
Chemical Vapor ◽  
Temperature Programmed Desorption ◽  
Etching Mechanism ◽  
Temperature Programmed ◽  
A Site ◽  
Site Blocking ◽  
Blocking Mechanism ◽  
Initial Sticking

ABSTRACTChlorine-containing precursors are attractive for chemical vapor deposition (CVD) of SiC because they are less hazardous and more economical than silane precursors. The reactivity of HCl, a by-product of these reactions, on SiC is of particular interest because it has been reported that HCl inhibits SiC CVD, but the mechanism for this inhibition has not been identified. In this work the adsorption of HCl on polycrystalline β-SiC was examined with Auger Electron Spectroscopy (AES) and Temperature Programmed Desorption (TPD). HCl adsorbs readily on SiC, with an initial sticking probability of 0.1 at 300 K, and forms a strong bond, with an activation energy for desorption of 64 kcal/mol. The only product detected by TPD is HCl, which desorbs in a peak centered at 1010 K. There are no Si- or C-containing desorption products, demonstrating that HCl does not etch SiC under TPD conditions. These results are consistent with a site-blocking mechanism for HCl inhibition of SiC CVD, but not with an etching mechanism.

The Reaction of NH3 With TiN: Implications for CVD

1995 ◽  
Vol 410 ◽  
Author(s):  
Michelle T. Schulberg ◽  
Mark D. Allendorf ◽  
Duane A. Outka
Keyword(s):  
Activation Energy ◽  
Chemical Vapor Deposition ◽  
Reaction Temperature ◽  
Vapor Deposition ◽  
High Probability ◽  
Film Growth ◽  
Chemical Vapor ◽  
Temperature Programmed Desorption ◽  
Surface Sites ◽  
Temperature Programmed

ABSTRACTSince NH3 is an important component of TiN chemical vapor deposition (CVD) processes, understanding the NH3/TiN surface interaction is crucial to developing a model for the overall reaction. Temperature programmed desorption experiments show that NH3 adsorbs molecularly on amorphous TiN surfaces. Chemisorption occurs at only ∼5% of the surface sites, with an activation energy for desorption of 24 kcal/mol. The sticking probability into this state is 0.06 at 100 K. In addition, NH3 adsorbs with high probability into a multilayer state with an activation energy for desorption of 7.3 kcal/mol, similar to that found in other systems. NH3 does not dissociate on TiN. Under CVD conditions, however, the reactivity of NH3 on TiN may increase and surface reactions may play a part in film growth.

Surface morphology and structure of hydrogen etched 3C-SiC(001) on Si(001)

2006 ◽  
Vol 911 ◽  
Author(s):  
Camilla Coletti ◽  
Martin Hetzel ◽  
Chariya Virojanadara ◽  
Ulrich Starke ◽  
Stephen E. Saddow
Keyword(s):  
Vapor Deposition ◽  
Atmospheric Pressure ◽  
Surface Defects ◽  
Chemical Vapor ◽  
Atomic Scale ◽  
Force Microscopy ◽  
Low Energy Electron Diffraction ◽  
Atomic Force ◽  
Different Temperatures ◽  
Low Energy Electron

AbstractThe surface of 3C-SiC(001) single-crystal epilayers grown on Si(001) substrates is well known to be inhomogeneous and defective. Therefore, the control and understanding at the atomic scale of 3C-SiC surfaces is a key issue. We study the effect of hydrogen etching at different temperatures on the morphology of 3C-SiC(001) surfaces by using Nomarksi optical microscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM). As-grown 3C-SiC(001) samples have been hydrogen etched in a horizontal hot-wall chemical vapor deposition (CVD) reactor at atmospheric pressure for different times and temperatures. Flat, high-quality surfaces presenting defined atomic terraces were observed within the 3C-SiC grain boundaries after etching at 1200°C for 30 minutes. Higher etching temperatures resulted in surfaces with step bunching and enlarged surface defects. Samples etched under the best conditions have been studied using low-energy electron diffraction (LEED) and Auger electron spectroscopy (AES).

Adsorption and Reaction of TiCl4 on W(100)

1993 ◽  
Vol 334 ◽  
Author(s):  
Wei Chen ◽  
Jeffrey T. Roberts
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Titanium Tetrachloride ◽  
Bound State ◽  
Temperature Programmed Desorption ◽  
X Ray ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Temperature Programmed

AbstractThe adsorption and reaction of titanium tetrachloride (TiC14) on W(100) was investigated using temperature programmed desorption mass spectrometry (TPRS), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and low energy electron diffraction (LEED). TiC14 adsorbs molecularly on W(100) at 100 K. Desorption from the molecularly bound state occurs near 220 K. Competing with desorption is dissociation to adsorbed TiCl3, which reacts to form gaseous TiCl4 near 450 K. TiC13 also decomposes into atomically adsorbed Ti and Cl on the surface upon heating to 700 K.

Surface Chemistry of Fluorine-Containing Molecules Related to CVD Process on Silicon Nitride: SiF4, XeF2, and HF

1991 ◽  
Vol 250 ◽  
Author(s):  
Duane A. Outka
Keyword(s):  
Silicon Nitride ◽  
Vapor Deposition ◽  
Electron Spectroscopy ◽  
Polycrystalline Silicon ◽  
Auger Electron ◽  
Chemical Vapor ◽  
Temperature Programmed Desorption ◽  
Auger Peak ◽  
Rate Determining Step ◽  
Temperature Programmed

AbstractThe reactivity of several fluorine-containing molecules on a polycrystalline silicon nitride (Si3N4) surface is studied under ultrahigh vacuum (UHV) conditions using temperature programmed desorption (TPD) and Auger electron spectroscopy (AES). The chemistry of fluorine on Si3N4 is of interest in understanding the high temperature chemical vapor deposition (CVD) of Si3N4, which uses SiF4 as a starting material. XeF2 is reacted with a Si3N4 surface to prepare and characterize various surface SiFx (1 ≤ × ≤ 3) species. These are identified by the chemical shift induced by the fluorine atoms in the Si (LMM) Auger peak and by changes in the TPD. Of these species, SiF2 is stable to the highest temperature. SiF2 is also formed by the reaction of SiF4 with a Si3N4. Because SiF2 is so stable, its decomposition is proposed as a rate-determining step in the CVD deposition of Si3N4 from SiF4. Gaseous HF, which is a product of the CVD process, does not dissociate on Si3N4 and is therefore unlikely to cause the etch-like marks on the Si3N4 coating that are observed under certain conditions.

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