Growth of SiO2 on Si(111)7×7 Using SiCl4 and H2O

1992 ◽  
Vol 282 ◽  
Author(s):  
Michael L. Wise ◽  
Lynne A. Okada ◽  
Peter A. Coon ◽  
Steven M. George
Keyword(s):  
Thermal Desorption ◽  
Atomic Layer ◽  
Reaction Scheme ◽  
Layer Growth ◽  
Silicon Surfaces ◽  
Surprising Result ◽  
Dangling Bond ◽  
Sequential Reaction ◽  
Temperature Programmed ◽  
Kinetics Of

ABSTRACTThe controlled atomic layer growth of SiO2 insulating layers on silicon surfaces might be achieved through the sequential reaction of SiCl4 and H2O:(A) Si-Cl + H2O → Si-OH + HCl(B) Si-OH + SiCl4 → Si-O-SiCl3 + HCl.To explore this ABAB… binary reaction scheme, laser-induced thermal desorption, temperature-programmed desorption, and Auger electron spectroscopy techniques were utilized to measure the kinetics of H2O oxidation of a Si(111)7×7 surface that had been previously subjected to a saturation SiCl4 exposure. Reaction kinetics studies for the oxidation of the chlorinated surface revealed that the rate of oxygen gain and the rate of chlorine loss were equal at reaction temperatures between 200 K and 700 K. These results were consistent with a direct substitution reaction according to:(A) Si-Cl + H2O → Si-OH + HCl.Above 700 K, the amount of oxygen gain became progressively greater than the amount of chlorine loss. This behavior was associated with the thermal desorption of H2 and the resultant formation of new dangling bond sites for H2O adsorption. For all temperatures, the oxidation kinetics of the chlorinated surface were nearly equivalent to the kinetics for the oxidation of clean silicon. This surprising result indicates that chlorine sites and free dangling bond sites react with equal probability to H2O. The kinetics of SiCl4 deposition were also measured on a Si(111)7×7 surface previously exposed to a saturation H2O dose. This chlorination reaction occurred at a much slower rate and was not as amenable to UHV studies.

Adsorption and Decomposition of Diethylsilane on Silicon Surfaces

1990 ◽  
Vol 204 ◽  
Author(s):  
P.A. Coon ◽  
M.L. Wise ◽  
A.C. Dillon ◽  
M.B. Robinson ◽  
S.M. George
Keyword(s):  
Atomic Layer ◽  
Silicon Surfaces ◽  
Desorption Kinetics ◽  
Surface Species ◽  
Temperature Dependent ◽  
Hydrogen Elimination ◽  
Elimination Mechanism ◽  
Temperature Programmed ◽  
Sticking Coefficients ◽  
Kinetics Of

ABSTRACTDiethylsilane (DES), Si(C2H5)2H2, is a promising candidate for the atomic layer epitaxy of silicon. The adsorption and decomposition kinetics of DES on silicon surfaces were studied using laser-induced thermal desorption (LITD), temperature programmed desorption (TPD), and Fourier transform infrared (FTIR) spectroscopy. FTIR studies on porous silicon surfaces indicated that DES dissociatively adsorbs below 600 K and produces Si-H and Si-C2H5 surface species. The desorption products following DES adsorption on Si(111) 7×7 were C2H4 and H2 for all surface coverages using both LITD and TPD techniques. Ethylene and H2 desorption occurred at 700 and 810 K, respectively, during TPD experiments with a heating rate of β = 9 K/s. Ethylene desorption was consistent with a β-hydrogen elimination mechanism from the Si-C2H2 surface species. Isothermal LITD studies monitored the desorption kinetics of C2 H4 from Sl (111) 7×7 as a function of time following DES exposures. The first-order ethylene desorption kinetics were Ed = 36 kcal/mol and vd = 2.7 × 109 s−1. Additional LITD measurements determined that le initial reactive sticking coefficient of DES on Si(111) 7×7 decreased versus surface temperature. The temperature-dependent sticking coefficients suggested a precursormediated adsorption mechanism.

Adsorption of Silicon Tetrachloride on Si(111) 7×7

1988 ◽  
Vol 131 ◽  
Author(s):  
P. Gupta ◽  
P. A. Coon ◽  
B. G. Koehler ◽  
S. M. George
Keyword(s):  
Surface Temperature ◽  
Thermal Desorption ◽  
Temperature Programmed Desorption ◽  
Silicon Tetrachloride ◽  
Sticking Coefficient ◽  
Adsorption Model ◽  
Temperature Programmed ◽  
Kinetics Of

ABSTRACTThe kinetics of SiCl4 adsorption on Si(lll) 7×7 were studied using laser induced thermal desorption (LITD) and temperature programmed desorption (TPD) techniques. The initial reactive sticking coefficient of SiCl4 on Si(lll) 7×7 was observed to decrease with increasing surface temperature. This decrease was consistent with a precursor-mediated adsorption model. Both LITD and TPD experiments monitored SiCl2 as the main desorption product. These results suggest that SiC12 may be the stable chlorine species on the Si(lll) 7×7 surface.

Atomic Layer Growth of SiO2 on Si(100) Using the Sequential Deposition of SiCl4 and H2O

1993 ◽  
Vol 334 ◽  
Author(s):  
Ofer Sneh ◽  
Michael L. Wise ◽  
Lynne A. Okada ◽  
Andrew W. Ott ◽  
Steven M. George
Keyword(s):  
High Pressure ◽  
Film Growth ◽  
Atomic Layer ◽  
Reaction Scheme ◽  
Layer Growth ◽  
Film Deposition ◽  
Layer By Layer ◽  
High Pressure Cell ◽  
Experimental Apparatus ◽  
Binary Reaction

AbstractThis study explored the surface chemistry and the promise of the binary reaction scheme:(A) Si-OH+SiCl4 → Si-Cl + HCl(B) Si-Cl + H2O → Si-OH + HClfor controlled SiO2 film deposition. In this binary ABAB… sequence, each surface reaction may be self-terminating and ABAB… repetitive cycles may produce layer-by-layer controlled deposition. Using this approach, the growth of SiO2 thin films on Si(100) with atomic layer control was achieved at 600 K with pressures in the 1 to 50 Torr range. The experiments were performed in a small high pressure cell situated in a UHV chamber. This design couples CVD conditions for film growth with a UHV environment for surface analysis using laser-induced thermal desorption (LITD), temperature-programmed desorption (TPD) and Auger electron spectroscopy (AES). The controlled layer-by-layer deposition of SiO2 on Si(100) was demonstrated and optimized using these techniques. A stoichiometric and chlorine-free SiO2 film was also produced as revealed by TPD and AES analysis. SiO2 growth rates of approximately 1 ML of oxygen per AB cycle were obtained at 600 K. These studies demonstrate the methodology of using the combined UHV/high pressure experimental apparatus for optimizing a binary reaction CVD process.

Deposition Sequences for Atomic Layer Growth of AlN Thin Films on Si(100) Using Dimethylethylamine Alane and Ammonia

1997 ◽  
Vol 482 ◽  
Author(s):  
Jason S. Kuo ◽  
J. W. Rogers
Keyword(s):  
Mass Spectrometry ◽  
Thin Films ◽  
Secondary Ion Mass Spectrometry ◽  
Atomic Layer ◽  
Layer Growth ◽  
Group V ◽  
Group Iii ◽  
Dimethylethylamine Alane ◽  
Temperature Programmed ◽  
Secondary Ion

AbstractRecent studies have demonstrated that dimethylethylamine alane (DMEAA) is a viable group III precursor for depositing high quality aluminum nitride thin films during atomic layer growth with ammonia as the group V source. However, a practical consideration that is questioned but seldom investigated is whether one should initiate the growth with the group III or the group V source. Clearly DMEAA interacts differently with silicon than does ammonia; hence, reversing the deposition sequence will lead to different interfacial composition. Earlier studies involving TMAA and ammonia indicate that direct interaction of group III precursor with the surface may lead to higher carbon contamination. In this work, adsorption of DMEAA on Si(100) and on ammonia-covered Si(100) are characterized with Temperature-Programmed Desorption (TPD), Secondary-Ion Mass Spectrometry (SIMS), and Temperature-Programmed Secondary-Ion Mass Spectrometry (TPSIMS). Preliminary results indicate that DMEAA adsorbs molecularly on both Si(100) and ammonia-covered Si(100), but to a much smaller coverage on the latter surface. Results from reversing the adsorption sequence, i.e. ammonia first then DMEAA, will be compared as a possibility for interfacial quality control.

Comparison of Trichlorosilane and Trichlorogermane Decomposition on Silicon Surfaces Using FTIR Spectroscopy

1992 ◽  
Vol 282 ◽  
Author(s):  
A. C. Dillon ◽  
M. B. Robinson ◽  
S. M. George
Keyword(s):  
Porous Silicon ◽  
High Surface ◽  
High Vacuum ◽  
Atomic Layer ◽  
Layer Growth ◽  
Ultra High Vacuum ◽  
Silicon Surfaces ◽  
Absorption Feature ◽  
Surface Species ◽  
Thermal Stabilities

ABSTRACTFourier transform infrared (FTIR) transmission spectroscopy was used to compare the decomposition of trichlorosilane (SiHCl3) and trichlorogermane (GeHCl3) on silicon surfaces. Chlorosilanes, such as SiHCl3 are employed in silicon chemical vapor deposition (CVD). Chlorosilanes and chlorogermanes are also possible molecular precursors for the controlled atomic layer growth of silicon and germanium. GeHCl3 may be useful for the deposition of germanium on silicon surfaces and the growth of Si1−xGex heterostructures. The FTIR studies were performed in-situ in an ultra-high vacuum chamber on high surface area, porous silicon samples. The FTIR spectra revealed that SiHCl3 dissociatively adsorbs at 200 K to form SiH, SiClx, ClSiH and Cl2SiH surface species. The presence of ClxSiH species is revealed by ClxSiH stretching (2196 cm−1) and bending (775, 744 cm−1) vibrations. The presence of these modes indicates that there is incomplete decomposition of SiHCl3 upon adsorption at 200 K. GeHCl3 also dissociatively adsorbs at 200 K to form SiH and SiClx species. An infrared absorption feature in the Ge-H stretching region (1970–1995 cm−1) was not detected in the FTIR spectrum. The absence of a Ge-H absorption feature argues that there is a complete transfer of hydrogen from germanium to surface silicon atoms at 200 K. The thermal stabilities of the surface species were studied with annealing experiments. The Clx SiH formed upon initial SiHCl3 exposures at 200 K were observed to decompose between 200–590 K and form additional surface SiH and SiCl species. For both GeHCl3 and SiHCl3 dissociative adsorption on porous silicon, the SiCL. (x = 2 or 3) surface species were converted to silicon monochloride surface species between 200–600 K. In addition, SiH surface species were lost upon annealing between 680–780 K as H2 desorbed from the surface. The adsorption kinetics of SiHCl3 and GeHCl3 were also monitored on porous silicon at various isothermal temperatures. These experiments provide insight into the surface chemistry of chlorosilanes and chlorogermanes during CVD and atomic layer controlled growth.

Oxidation Kinetics of Silicon Surfaces: Reactive Sticking Coefficient, Apparent Saturation Coverage and Effect of Surface Hydrogen

1988 ◽  
Vol 131 ◽  
Author(s):  
S. M. George ◽  
P. Gupta ◽  
C. H. Mak ◽  
P. A. Coon
Keyword(s):  
Surface Temperature ◽  
Silicon Surfaces ◽  
Sticking Coefficient ◽  
Initial Oxidation ◽  
Surface Hydrogen ◽  
Oxygen Coverage ◽  
Saturation Coverage ◽  
Temperature Programmed ◽  
Kinetics Of ◽  
Effect Of Surface

ABSTRACTThe kinetics of the initial oxidation of silicon surfaces by O2 were studied using laser-induced thermal desorption (LITD), temperature programmed desorption (TPD) and Fourier Transform Infrared (FTIR) spectroscopy. The LITD results showed that the oxidation of Si(111)7×7 by O2 was characterized by two kinetic processes: an initial rapid oxygen uptake followed by a slower growth that asymptotically approached an apparent saturation oxygen coverage. The initial reactive sticking coefficient of O2 on Si(111)7×7 decreased with surface temperature. In contrast, TPD experiments on Si(111)7×7 and FTIR studies on porous silicon demonstrated that the apparent saturation oxygen coverage increased as a function of surface temperature. Experiments with preadsorbed hydrogen also revealed that silicon oxidation was inhibited as a function of increasing hydrogen coverage on the Si(111)7×7 surface.

Competitive Pairing and the Chemistry of Coadsorbed Hydrogen and Halogens on Ge(100)

1992 ◽  
Vol 282 ◽  
Author(s):  
Yuemei L. Yang ◽  
Stephen M. Cohen ◽  
Mark P. D'Evelyn
Keyword(s):  
Epitaxial Growth ◽  
Atomic Layer ◽  
Temperature Programmed Desorption ◽  
Model System ◽  
Atomic Layer Epitaxy ◽  
Desorption Kinetics ◽  
First Order ◽  
First Order Kinetics ◽  
Temperature Programmed ◽  
Kinetics Of

ABSTRACTThe chemistry of coadsorbed H and X (X=C1, Br) on semiconductor surfaces is important in epitaxial growth of silicon from chlorosilanes and of SixGe1−x alloys, in hydrogenating/ halogenating cycles in atomic layer epitaxy, and also provides an interesting model system, yet has received little attention to date. We have investigated the interaction of HC1 and HBr with Ge(100) by temperature-programmed desorption, and find that H2, HCl and HBr each desorb with near-first-order kinetics near 570–590 K and that GeCl2 and GeBr2 desorb with near-second-order kinetics near 675 K and 710 K, respectively. Analysis of the desorption kinetics of H2 and HX provides evidence that adsorbed H and X atoms pair preferentially in a qualitatively similar way as H atoms adsorbed alone on Ge(100)2×1 or Si(100)2×1 and that pairing of H+X occurs in competition with pairing of H+H.

The mechanism of the anionic coordination polymerization of isoprene

1980 ◽  
Vol 45 (9) ◽  
pp. 2391-2399 ◽  
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval
Keyword(s):  
Chromatographic Method ◽  
Initial Period ◽  
Reaction Scheme ◽  
Polymerization Kinetics ◽  
Coordination Polymerization ◽  
Initial Concentration ◽  
The Cross ◽  
Gas Chromatographic Method ◽  
Kinetics Of

The polymerization kinetics of isoprene (2-methyl-1,3-butadiene) in benzene with butyllithium as the initiator was investigated by the gas chromatographic method. After completion of the initial period of the reaction, its order with respect to the initial concentration of initiator is negative at the concentrations of the latter between 0.01 and 0.25 mol/l, and positive at higher concentrations. A reaction scheme has been suggested with respect to the "cross" association of butyllithium and of the "living" oligoisoprene.

The effect of electrondonors on the polymerization kinetics of isoprene

1980 ◽  
Vol 45 (12) ◽  
pp. 3338-3346
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval
Keyword(s):  
Induction Period ◽  
Ethyl Ether ◽  
Reaction Order ◽  
Propagation Rate ◽  
Reaction Scheme ◽  
Polymerization Kinetics ◽  
Polymerization Rate ◽  
Constant Concentration ◽  
Initial Concentration ◽  
Kinetics Of

The effect of small additions of 1-octene, butyl ethyl ether and triethylamine on the polymerization kinetics of isoprene (2-methyl-1,3-butadiene) in benzene initiated with butyllithium was investigated by employing the GLC analysis. The addition of 1-octane was reflected only in a shorter induction period of the reaction; the effect on the propagation rate was insignificant. With the increasing amount of butyl ethyl ether, the polymerization rate increases linearly, while the reaction order with respect to the concentration of triethylamine is variable and increases from 0.33 to 0.66 with the increasing concentration of the initiator. For a constant concentration of triethylamine, the reaction order with respect to the initial concentration of the initiator was found to vary considerably, reaching even negative values. A reaction scheme was suggested, taking into account the competition between two different solvates of alkyllithium.

Kinetics of temperature-programmed reactivation of a hydrodesulphurization catalyst

1983 ◽  
Vol 48 (12) ◽  
pp. 3340-3355 ◽  
Author(s):  
Pavel Fott ◽  
Pavel Šebesta
Keyword(s):  
Carbon Dioxide ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thin Layer ◽  
Kinetic Parameters ◽  
Diffusion Region ◽  
Reaction Heat ◽  
Gaseous Products ◽  
Temperature Programmed ◽  
Kinetics Of

The kinetic parameters of reactivation of a carbonized hydrodesulphurization (HDS) catalyst by air were evaluated from combined thermogravimetric (TG) and differential thermal analysis (DTA) data. In addition, the gaseous products leaving a temperature-programmed reactor with a thin layer of catalyst were analyzed chromatographically. Two exothermic processes were found to take part in the reactivation, and their kinetics were described by 1st order equations. In the first process (180-400 °C), sulphur in Co and Mo sulphides is oxidized to sulphur dioxide; in the second process (300-540 °C), in which the essential portion of heat is produced, the deposited carbon is oxidized to give predominantly carbon dioxide. If the reaction heat is not removed efficiently enough, ignition of the catalyst takes place, which is associated with a transition to the diffusion region. The application of the obtained kinetic parameters to modelling a temperature-programmed reactivation is illustrated on the case of a single particle.

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