Horizontal Hot-wall Reactor Research Articles

Numerical modeling of SiC–CVD in a horizontal hot-wall reactor

A numerical simulation was carried out on SiC–CVD in a horizontal hot-wall reactor. In order to explain the effect of surface polarity, Si-face and C-face, the surface reaction model was improved. Then, the growth processes and doping features of both Si-face and C-face were analyzed. The role of conditions at growing surface, such as surface mass flux of both Si-containing and C-containing species, surface concentration of Si-containing and C-containing species and their ratio, is investigated. Then, the deposition and etching rates, and doping concentration are analyzed as the function of those parameters. In addition, surface morphology of growing epitaxial layer is also investigated in connection with growing surface condition.

Horizontal hot wall reactor design for epi‐SiC growth

AbstractThe model adopted for the simulation of a new industrial size type of horizontal cold wall reactor for epitaxial silicon carbide deposition is reviewed. The attention is focalized on the chemical mechanism adopted and on the comparison with some growth rate data and temperature profiles for the system ethylene, silane, hydrogen and the deposition of undoped silicon carbide. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Cobalt hexafluoroacetylacetonate polyether adducts for thin films of cobalt oxides

The novel [Co(C 5F 6HO 2) 2 · 2H 2O · CH 3(OCH 2CH 2) 2OCH 3] and [Co(C 5F 6HO 2) 2 · 2H 2O · CH 3(OCH 2CH 2) 3OCH 3] low-melting adducts have been synthesized and characterized by elemental analysis, IR spectroscopy, mass spectra and TG–DTG thermal measurements. The former adduct is liquid at room temperature, whilst very mild heating of the latter results in a thermal stable liquid compound. Both adducts can easily be evaporated. Deposition experiments, in a low-pressure horizontal hot-wall reactor, on optical transparent SiO 2 substrates, using these precursors, result in CoO or Co 3O 4 films, depending on the deposition conditions. XRD measurements provide evidence that CoO and Co 3O 4 consist of cubic, highly oriented, (2 0 0) and (3 1 1) crystals, respectively. The mean crystallite sizes were evaluated from the XRD line broadening. Both optical spectra and resistivity measurements of Co 3O 4 films show that they are semi-conducting and their band-gap was determined from the optical induced transitions. The film cross section and the surface atomic composition were investigated by SEM and XPS analyses, respectively.

Numerical Analysis of Growth Condition on SiC-CVD in the Horizontal Hot-Wall Reactor

Growth, etching, and doping features of SiC-CVD in a horizontal hot-wall reactor were numerically analyzed using the improved heterogeneous model. The improved model was able to explain the growth and etching features accurately. In addition, we propose the surface flux, surface carbon and silicon concentration, and its ratio as the universal parameter of the SiC-CVD process. Concerning doping features, the improved model showed that nitrogen and aluminum doping incorporation could be explained by the site competition model, while taking into account the amount of surface silicon and surface carbon, respectively.

Modeling of SiC-CVD on Si-face/C-face in a horizontal hot-wall reactor

To explain the difference between SiC-CVD on the Si-face and C-face, a heterogeneous model was improved, in which the etching, growth and doping features of SiC-CVD in a horizontal hot-wall reactor were numerically analyzed. The improved model was able to explain the etching and growth features accurately. There was no difference between the Si- and C-face. In addition, we propose the surface C/Si ratio as the universal parameter of the SiC-CVD process. Concerning doping features, the improved model showed that nitrogen and aluminum doping incorporation could be explained by the site competition model, while taking into account the amount of surface silicon and surface carbon, respectively.

Modeling of epitaxial silicon carbide deposition

The availability of reliable chemical kinetics data is still a key factor in designing epitaxial deposition reactors able to obtain electronic grade surface quality for SiC films. Here, a literature mechanism was considered for the gas phase while a new multi species surface one was introduced. That detailed mechanism was embedded in a series of reactor models of different complexity (1D–3D) to realize a multi hierarchy modeling approach. In the framework of horizontal hot wall reactor with multiwafer rotating susceptor, several process parameters were examined.

Modeling and simulation of SiC CVD in the horizontal hot-wall reactor concept

This paper summarizes recent experimental and simulation results on etching, growth rates and nitrogen incorporation in silicon carbide epitaxial layers grown in a horizontal hot-wall chemical vapor deposition reactor. The combination of heat and mass transfer modeling, process simulation and experimental studies allows the identification and the quantification of the growth and doping histories. It is demonstrated that, in this high temperature technology, (a) it is difficult to optimize the deposition rate uniformity for large-scale substrates and (b) hydrogen etching during growth is of great importance. Finally, new results concerning the influence of hydrogen etched nitrogen on the nitrogen doping profile in the epilayer are shown. A simple model taking only into account N 2 adsorption is not sufficient to correctly explain the doping variations. Specific experiments have been realized to identify and quantify additional phenomena such as the etching of nitrogen by H 2 during the deposition process.

Modeling and simulation of SiC CVD in the horizontal hot-wall reactor concept

Modeling and simulation of SiC CVD in the horizontal hot-wall reactor concept

Viable route for the synthesis of the anhydrous Co(hfac)2adduct with monoglyme: a useful precursor for thin films of CoO

The [Co(hfac)2·CH3OCH2CH2OCH3] adduct was synthesised and investigated by X-ray crystal structure, mass spectra, TG-DTG thermal measurements and infrared transmittance spectroscopy. X-Ray single crystal data provide evidence of a slightly distorted octahedral cobalt cation, coordinated with four oxygen atoms of two hfac anions and two oxygens of the monoglyme molecule. Deposition experiments, in a low-pressure horizontal hot-wall reactor, on optically transparent SiO2 substrates, using the title complex, resulted in CoO films. XRD measurements show that CoO consists of cubic, highly oriented, crystals. The surface atomic composition of the films was investigated by XPS. No fluorine contamination was detected.

Uniformity of 4H–SiC epitaxial layers grown on 3-in diameter substrates

Uniformity of thickness and carrier concentration of homo-epitaxial films grown on 3-in diameter 4H–SiC substrates using a horizontal hot-wall reactor has been investigated. From the comparison between the experimental results and temperature and gas flow simulation, it is found that the thickness (growth rate) distribution is closely related to the gas velocity distribution, and the carrier concentration distribution has strong correlation with the temperature distribution not on the surface of the susceptor plate but in the gas phase. It is pointed out that the growth rate uniformity of 3-in diameter wafer is degraded by the gas flow disturbance near the susceptor’s side walls, and the carrier concentration uniformity is strongly related to the gas phase reaction of nitrogen containing species, such as N 2 and/or others.

Large Third-Order Nonlinear Optical Properties of Cadmium Oxide Thin Films

This study represents the first investigation on CdO films by the z-scan technique. Deposition experiments in a low-pressure horizontal hot-wall reactor on SiO2 substrates result in CdO thin films that show large third-order nonlinear optical properties. Optical properties of CdO were tuned by varying the deposition conditions. AFM images suggest that MOCVD under more oxidizing condition results in smaller crystal sizes. The decrease of the particle dimension causes larger optical nonlinearity. Monotonic increase of the χ(3) values with the increase of the laser pulse duration is observed by comparing our results with similar literature data for metal oxides.

Effect of Cl/H input ratio on the growth rate of MoSi 2 coatings formed by chemical vapor deposition of Si on Mo substrates from SiCl 4–H 2 precursor gases

Under chemical vapor deposition (CVD) conditions of Si on Mo substrate limited by mass transport of reactant gas species through a gas boundary layer, the effect of the Cl/H input ratio on the growth rate of MoSi 2 coating at 1200 °C was investigated using a horizontal hot-wall reactor and SiCl 4–H 2 gas mixtures. The growth kinetic of the MoSi 2 coating obeyed a parabolic rate law irrespective of Cl/H input ratios. The growth rate of MoSi 2 coating initially increased with increasing Cl/H input ratio until the maximum growth rate was reached, and then decreased inversely proportional to the Cl/H input ratio at higher Cl/H input ratio. This suggests that there is a limit to the increase in growth rate for MoSi 2 coating due to the etching effect of Si with respect to the input ratio of Cl/H. The etching effect of the Cl/H input ratio on the growth rate of the MoSi 2 coating was explained by thermodynamic calculations based on the variation of silicon activity on the surface of the MoSi 2 coating. The mass balance between the Si flux supplied by the mass transport step and that consumed by solid-state diffusion to form MoSi 2 coating was considered to be responsible for the activity of silicon.

Formation process and microstructural evolution of Ni-silicide layers grown by chemical vapor deposition of Si on Ni substrates

The formation process and microstructural evolution of Ni-silicide layers formed by chemical vapour deposition (CVD) of Si on Ni substrate at deposition temperatures between 900 and 1050 °C using horizontal hot-wall reactor and SiCl 4–H 2 gas mixtures was investigated. The Ni-silicide layers grew sequentially in a series of γ-Ni 5Si 2, δ-Ni 2Si and θ-Ni 2Si layers with increasing deposition time. After an incubation time necessary for nucleation of each Ni-silicide phase, the growth kinetics of each layer obeyed a parabolic rate law and was controlled by solid-state diffusion of Ni leading to void formation at the interface of the Ni-silicide layers and the Ni substrate. The growth rates of γ-Ni 5Si 2 and δ-Ni 2Si layers were faster at the early deposition stage than those at the later deposition stage. The formation process and microstructures of each Ni-silicide layer was influenced by the effect of deposition parameters especially on the difference between the Si flux supplied by CVD process and the Ni flux diffusing through each Ni-silicide layer.

Synthesis and Characterization of Liquid MOCVD Precursors for Thin Films of Cadmium Oxide.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis and Characterization of Liquid MOCVD Precursors for Thin Films of Cadmium Oxide

Four novel Cd(C5F6HO2)2·polyether adducts were prepared through simple procedures with stoichiometric quantities of cadmium oxide, hexafluoroacetylacetone C5F6H2O2, and different polyethers. The products were characterized by elemental analysis, X-ray single-crystal analysis, mass spectra, NMR spectra, thermal measurements, and infrared transmittance spectroscopy. X-ray single-crystal data of the Cd(C5F6HO2)2·polyether adducts showed that all the oxygen atoms of the polyether molecules coordinate the cadmium cation. Very mild heating (44−74 °C) resulted in thermal stable, liquid compounds which, in turn, can be easily evaporated. Gas-phase deposition experiments, in a low-pressure horizontal hot-wall reactor, on SiO2 substrates, resulted in CdO films. XRD measurements provided evidence that they consist of cubic, (100)-oriented, crystals. UV−vis spectra showed that the transmittance of as-deposited films in the visible region is about 90%.

C-Axis oriented (Na,K)NbO 3 thin films on Si substrates using metalorganic chemical vapor deposition

Ferroelectric (Na,K)NbO 3 (NKN) thin films were synthesized using metalorganic chemical vapor deposition (MOCVD) technique for the first time. The films are deposited on Si substrates with amorphous insulating layers in a horizontal hot-wall reactor using tetramethylheptanedionate (THD) precursors. 100% [001] oriented texturing with narrow mosaic broadening was achieved in the films both on SiO 2/Si and SiN x /Si substrates. Electron Spectroscopy for Chemical Analysis (ESCA) analysis indicated that Na, K, Nb, and O are the primary elements present in the film. Dielectric spectroscopy for NKN films on SiO 2/Si substrates showed dielectric permittivity ε′ about 140 and loss tan δ less than 2% in the frequency range from 1 to 100 kHz. Current–voltage ( I– V) measurements for this film showed low current density of ∼10 −8 A/cm 2 at the field of 200 kV/cm.

Synthesis and Characterization of Thin Films of Cadmium Oxide

The Cd(C5F6HO2)2·2H2O complex was investigated by X-ray crystallography, mass spectroscopy, 1H NMR spectroscopy, TG−DTG thermal measurements, and infrared transmittance spectroscopy. X-ray single-crystal data show that the cadmium ion is chelated by the oxygens of the hfa anion ligand and bound to the oxygens of two cis-disposed water molecules. Deposition experiments, in a low-pressure horizontal hot-wall reactor, on optically transparent SiO2 substrates using the above complex result in CdO films. XRD measurements provide evidence that these complexes consist of highly oriented cubic crystals. UV−vis spectra show that the transmittance of as-deposited films in the visible region is about 70%. The surface structure of the CdO films was investigated by XPS. Resistivity measurements of the CdO films suggest TCO properties.

(Na,K)NbO 3 Thin Films Using Metal-Organic Chemical Vapor Deposition

Ferroelectric (Na,K)NbO 3 (NKN) thin films have been synthesized using metalorganic chemical vapor deposition (MOCVD) technique for the first time. The films were deposited on various substrates in a horizontal hot-wall reactor using tetramethyl-heptanedionate (THD) precursors. Epitaxial films have been prepared on SrTiO 3 (001) substrates, while nearly perfect [001]-axis oriented polycrystalline thin films have been deposited on SiO 2 /Si, SiN x /Si, and sapphire substrates. Electron Spectroscopy for Chemical Analysis (ESCA) analysis indicated that Na, K, Nb, and O are the primary elements present in the film. Dielectric spectroscopy for NKN films on SiO 2 /Si substrates showed dielectric permittivity l ' about 140 and loss tan i less than 2 % in the frequency range from 1 kHz to 120 kHz.

(Na,K)NbO 3 Thin Films Using Metal-Organic Chemical Vapor Deposition

Ferroelectric (Na,K)NbO 3 (NKN) thin films have been synthesized using metalorganic chemical vapor deposition (MOCVD) technique for the first time. The films were deposited on various substrates in a horizontal hot-wall reactor using tetramethyl-heptanedionate (THD) precursors. Epitaxial films have been prepared on SrTiO 3 (001) substrates, while nearly perfect [001]-axis oriented polycrystalline thin films have been deposited on SiO 2 /Si, SiN x /Si, and sapphire substrates. Electron Spectroscopy for Chemical Analysis (ESCA) analysis indicated that Na, K, Nb, and O are the primary elements present in the film. Dielectric spectroscopy for NKN films on SiO 2 /Si substrates showed dielectric permittivity l ' about 140 and loss tan i less than 2 % in the frequency range from 1 kHz to 120 kHz.

Epitaxial silicon carbide simulations vs. experiments: etching, growth rates and aluminum/nitrogen doping

ABSTRACTThis paper summarizes recent experimental and simulation results on etching, growth rates and aluminum/nitrogen incorporation in SiC epitaxial layers grown in a horizontal LPCVD hotwall reactor commercialized by the Epigress company. The combined use of modeling and experiments allows to identify and to quantify the main growth phenomena. In this paper, a chemistry model including surface deposition and hydrogen etching is first described. It is found that the contribution of the etching of the susceptor to the SiC growth is not negligible. A simple model is used to describe nitrogen incorporation.