A polycentric growth model of gallium arsenide epitaxial layers from the gas phase with simultaneous diffusion, adsorption and chemical reaction

1988 ◽  
Vol 53 (12) ◽  
pp. 2995-3013
Author(s):  
Emerich Erdös ◽  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma
Keyword(s):  
Growth Rate ◽  
Gallium Arsenide ◽  
Epitaxial Growth ◽  
Gas Phase ◽  
Surface Reaction ◽  
Quantitative Description ◽  
The Other ◽  
Rate Equations ◽  
Impact Interaction ◽  
Partial Pressures

For a quantitative description of the epitaxial growth rate of gallium arsenide, two models are proposed including two rate controlling steps, namely the diffusion of components in the gas phase and the surface reaction. In the models considered, the surface reaction involves a reaction triple - or quadruple centre. In both models three mechanisms are considered which differ one from the other by different adsorption - and impact interaction of reacting particles. In every of the six cases, the pertinent rate equations were derived, and the models have been confronted with the experimentally found dependences of the growth rate on partial pressures of components in the feed. The results are discussed with regard to the plausibility of individual mechanisms and of both models, and also with respect to their applicability and the direction of further investigations.

A dual site growth model of gallium arsenide epitaxial layers from the gas phase

1987 ◽  
Vol 52 (5) ◽  
pp. 1131-1159
Author(s):  
Emerich Erdös ◽  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma
Keyword(s):  
Growth Rate ◽  
Gallium Arsenide ◽  
Gas Phase ◽  
Quantitative Description ◽  
The Other ◽  
Rate Equations ◽  
Partial Pressures ◽  
The Individual ◽  
Rate Controlling Step ◽  
Dual Site

For a quantitative description of the epitaxial growth rate of gallium arsenide, a model is proposed including two rate controlling steps. One of these steps is the diffusion of gaseous components between the gas phase and the epitaxial layer surface, and the other step is of chemical nature, i.e. either the surface reaction or adsorption or desorption of one of the gaseous components. In the model considered, an active dual site is involved in the second rate controlling step, and twelve mechanisms are proposed for which the pertinent rate equations are derived. The individual mechanisms differ one from the other not only by the kind of the rate controlling step but also by the occupation of the dual site, viz. in the both direct and reversed direction. The proposed model is confronted with the dependences of the growth rate on partial pressures of components in the feed found by experiment. The results are discussed with regard to the possibility of individual mechanisms and of the model as a whole, and also with respect to their applicability and to the direction of further investigations.

A quantitative model of epitaxial layers growth from the gas phase with a simultaneous participation of diffusion, adsorption, and chemical reaction

1986 ◽  
Vol 51 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Emerich Erdös ◽  
Jiří Laitner ◽  
Josef Stejskal ◽  
Přemysl Klíma
Keyword(s):  
Growth Rate ◽  
Gas Phase ◽  
Epitaxial Layer ◽  
Chemical Nature ◽  
Quantitative Description ◽  
Physical Nature ◽  
Rate Equations ◽  
Layer Surface ◽  
Active Centre ◽  
Rate Controlling Step

For a quantitative description of the epitaxial growth rate of gallium arsenide, a model has been proposed including two rate controlling steps, namely one step of physical nature and the other one of chemical nature. As the step of physical nature, the diffusion of gaseous components between the gas phase and the epitaxial layer surface has been considered, and from the steps of chemical nature the adsorption of gaseous components on the epitaxial layer surface and a heterogenous surface reaction have been taken into account. According to the kind of the chemical rate controlling step, five mechanisms have been proposed, where a one - centre model was used in all cases, i.e. the idea that the rate controlling step takes place under participation of one active centre. For all the mechanisms considered, the pertaining rate equations have been derived, which were confronted with the experimentally found dependences of the growth rate on partial pressures of components in the feed. The results are discussed both from the view point of plausibility of individual mechanisms and from the point of view of their applicability and of the next research direction.

Direct Nucleation of Crystalline SiGe on Substrates by Reactive Thermal CVD with Si2H6 and GeF4

1997 ◽  
Vol 467 ◽  
Author(s):  
Fumio Yoshizawa ◽  
Kunihiro Shiota ◽  
Daisuke Inoue ◽  
Jun-ichi Hanna
Keyword(s):  
Growth Rate ◽  
Gas Phase ◽  
Heterogeneous Nucleation ◽  
Homogeneous Nucleation ◽  
Film Growth ◽  
Early Stage ◽  
Gaseous Mixture ◽  
The Other ◽  
Thermal Cvd ◽  
Initial Deposition

ABSTRACTPolycrystalline SiGe (poly-SiGe) film growth by reactive thermal CVD with a gaseous mixture of Si2H6 and GeF4 was investigated on various substrates such as Al,Cr, Pt, Si, ITO, ZnO and thermally grown SiO2.In Ge-rich film growth, SEM observation in the early stage of the film growth revealed that direct nucleation of crystallites took place on the substrates. The nucleation was governed by two different mechanisms: one was a heterogeneous nucleation on the surface and the other was a homogeneous nucleation in the gas phase. In the former case, the selective nucleation was observed at temperatures lower than 400°C on metal substrates and Si, where the activation of adsorbed GeF4 on the surface played a major role for the nuclei formation, leading to the selective film growth.On the other hand, the direct nucleation did not always take place in Si-rich film growth irrespective of the substrates and depended on the growth rate. In a growth rate of 3.6nm/min, the high crystallinity of poly-Si0.95Ge0.05in a 220nm-thick film was achieved at 450°C due to the no initial deposition of amorphous tissue on SiO2 substrates.

Role of Cl/Si Ratio in the Low-Temperature Chloro-Carbon Epitaxial Growth of SiC

2013 ◽  
Vol 740-742 ◽  
pp. 205-208
Author(s):  
Galyna Melnychuk ◽  
Siva Prasad Kotamraju ◽  
Yaroslav Koshka
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Epitaxial Growth ◽  
Growth Process ◽  
Growth Conditions ◽  
The Other ◽  
Additional Increase ◽  
Other Hand

In order to understand the influence of the Cl/Si ratio on the morphology of the low-temperature chloro-carbon epitaxial growth, HCl was added during the SiCl4/CH3Cl growth at 1300°C. Use of higher Cl/Si ratio allowed only modest improvements of the growth rate without morphology degradation, which did not go far beyond what has been achieved previously by optimizing the value of the input C/Si ratio. On the other hand, when the epitaxial growth process operated at too low or too high values of the input C/Si ratio, i.e., outside of the window of good epilayer morphology, any additional increase of the Cl/Si ratio caused improvement of the epilayer morphology. It was established that this improvement was due to a change of the effective C/Si ratio towards its intermediate values, which corresponded to more favorable growth conditions.

Increased Growth Rate in a SiC CVD Reactor Using HCl as a Growth Additive

2005 ◽  
Vol 483-485 ◽  
pp. 73-76 ◽  
Author(s):  
Rachael L. Myers-Ward ◽  
Olof Kordina ◽  
Z. Shishkin ◽  
Shailaja P. Rao ◽  
R. Everly ◽  
...  
Keyword(s):  
Growth Rate ◽  
Epitaxial Growth ◽  
Gas Phase ◽  
Hydrogen Chloride ◽  
Growth Rates ◽  
Growth Process ◽  
Cluster Formation ◽  
Film Morphology ◽  
Hydrogen Carrier ◽  
Low Crystalline

Hydrogen chloride (HCl) was added to a standard SiC epitaxial growth process as an additive gas. A low-pressure, hot-wall CVD reactor, using silane and propane precursors and a hydrogen carrier gas, was used for these experiments. It is proposed that the addition of HCl suppresses Si cluster formation in the gas phase, and possibly also preferentially etches material of low crystalline quality. The exact mechanism of the growth using an HCl additive is still under investigation, however, higher growth rates could be obtained and the surfaces were improved when HCl was added to the flow. The film morphology was studied using SEM and AFM and the quality with LTPL analysis, which are reported.

Use of SiCl4 as Silicon Precursor for Low-Temperature Halo-Carbon Epitaxial Growth of 4H-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 111-114 ◽  
Author(s):  
Siva Prasad Kotamraju ◽  
Bharat Krishnan ◽  
Galyna Melnychuk ◽  
Yaroslav Koshka
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Epitaxial Growth ◽  
Gas Phase ◽  
Homogeneous Nucleation ◽  
Process Window ◽  
Carbon Precursor ◽  
Optimal Value ◽  
Similar Growth ◽  
Si Supply

Chlorinated silicon precursor SiCl4 was investigated as an alternative to SiH4 with HCl addition as a source of additional chlorine in order to suppress the homogeneous nucleation during the low-temperature epitaxial growth at 1300°C. The homogeneous nucleation in the gas phase was further reduced compared to SiH4+HCl growth. The process window for obtaining good epilayer morphology during the CH3Cl/SiCl4 growth was found to correspond to Si supply-limited mode. At lower values of C/Si ratio formation of Si-rich polycrystalline islands/droplets took place. At high C/Si ratio, formation of polycrystalline SiC was the source of morphology degradation. The process window became increasingly narrower at higher Rg, which limited the possibility of significantly increasing Rg at such low growth temperatures. Generation of triangular defects became significant at Rg above 5-6 μm/hr, even when a nearly-optimal value of C/Si ratio was used. Similar experiments were conducted using C3H8, a more traditional precursor, instead of the halo-carbon precursor CH3Cl. While a similar growth rate could be achieved for the same SiCl4 flow rate, much lower values of the C/Si ratio were required. The morphology with C3H8 was worse within the process window. The C/Si process window for the C3H8/SiCl4 growth was much narrower compared to the CH3Cl/SiCl4 growth, and the window essentially disappeared at Rg > 3 4 μm/hr.

A dual equilibrium diffusion model for epitaxial growth of gallium arsenide layers from the gas phase and an a priori computation of growth rates

1984 ◽  
Vol 49 (11) ◽  
pp. 2425-2436 ◽  
Author(s):  
Emerich Erdös ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma
Keyword(s):  
Gallium Arsenide ◽  
Epitaxial Growth ◽  
Gas Phase ◽  
Growth Rates ◽  
Diffusion Coefficients ◽  
A Priori ◽  
Boundary Layer Theory ◽  
View Point ◽  
Chemical Equilibria ◽  
Rate Controlling Step

A model is proposed and quantitatively treated of epitaxial growth of gallium arsenide layers, where the rate controlling step consists in the diffusion of reactants through a stagnant gas film adhering to the substrate, and where chemical equilibria are established between the reactants in the main gas stream and at the surface of substrate. The boundary layer theory is applied to the hydrodynamic part of the model which is simplified by introducing a mean effective film thickness, and the system of Ga-As-Cl-H is reduced to six molecular species and to three chemical reactions. With this basis and using estimated values of diffusion coefficients, the growth rates of epitaxial gallium arsenide layers have been a priori computed in dependence of the feed rate, its composition and on temperature. The predicted three dependences are discussed from the view-point of their courses and of the significance of computed results.

Do gas phase adducts form during metalorganic vapour phase epitaxial growth of gallium arsenide?

1994 ◽  
Vol 145 (1-4) ◽  
pp. 104-112 ◽  
Author(s):  
Douglas F. Foster ◽  
Christopher Glidewell ◽  
David J. Cole-Hamilton ◽  
Ian M. Povey ◽  
Richard D. Hoare ◽  
...  
Keyword(s):  
Gallium Arsenide ◽  
Epitaxial Growth ◽  
Gas Phase ◽  
Vapour Phase

scholarly journals Die Kinetik des thermischen Zerfalls von ClNO2 / Thermal Decomposition of ClNO2

1978 ◽  
Vol 33 (9) ◽  
pp. 1037-1047 ◽  
Author(s):  
H.-D. Knauth ◽  
H. Martin
Keyword(s):  
Thermal Decomposition ◽  
Time Dependence ◽  
Gas Phase ◽  
Reaction Scheme ◽  
The Other ◽  
Rate Equations ◽  
Standard State ◽  
Inert Solvent ◽  
State 1 ◽  
Overall Reactions

ClNO2 decomposes incompletely at temperatures between 353 K and 373 K in the nonpolar inert solvent C7F15Cl according to 2 ClNO2=2 NO2+Cl2. (a) Some ClNO is formed as by-product according to 2 ClNO2 = 2 ClNO+O2 . (b) The reactions were followed photometrically by the arising NO2 . The time dependence of the brutto-reaction is described on the basis of the reaction scheme ClNO2⇄NO2+Cl (1, - 1); NO3+NO2⇄NO+O2+NO2 (5, - 5); ClNO2+ClNO2⇄Cl2+2NO2 (2, - 2); NO+ClNO2⇄ClNO+NO2 (6, - 6); Cl+ClNO2⇄Cl2+NO2 (3, - 3); ClNO+ClNO2⇄NO±Cl2+NO2 (7, - 7);NO2+ClNO2⇄NO3±ClNO (4, - 4); Cl+ClNO⇄Cl2+NO (8, - 8). Arrhenius parameters for the steps (1) and (2) were obtained: A1/s-1 = 1016.47±0.78, E1/kJ mol-1 = 152.3 ± 5.4;A2/cm3 mol-1 s-1 = 1012.99±0.02 E2/kJ mol-1 = 88.7 ± 0.8. The other parameters entering the rate equations were determined at 373 K as k-1/k3 = 1.5 ± 0.3; k4/cm3 mol-1 s-1 = 0.17; k7/cm3 mol-1 s-1 = 11.2. The enthalpies and entropies of the overall reactions (a), (b) and N2O4 = 2 NO2 (c) were measured directly (c) or indirectly: (a) (b) (c) ⊿RH/kJ mol-1 46.4 83.7 65.3 ⊿RS/J K -1 mol-1 61.8 85.7 97.8 (standard state 1 mol cm-3, T = 363 K). Former investigations of the reaction in the gas phase and in solution which were interpreted exceptionally by step (1) followed by the fast step (3) are now interpreted on the basis of the new reaction scheme discussed here and are found to be consistent with it.

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