scholarly journals Effect of Nonhydrostatic Stress on Crystal Growth Kinetics

1990 ◽  
Vol 202 ◽  
Author(s):  
Michael J. Aziz ◽  
Paul C. Sabin ◽  
Guo-Quan Lu

ABSTRACTThe effect of nonhydrostatic stresses on the solid phase epitaxial growth rate of crystalline Si(100) into self-implanted amorphous surface layers has been measured. Uniaxial stresses of up to 6 kbar (0.6 GPa) were attained by bending wafers over SiO2 rods and annealing at a temperature too low for plastic deformation to relieve the stress in the crystal, but high enough for solid phase epitaxial growth to proceed. The growth rate on the tensile side was greater than that on the compressive side of the wafer, in marked contrast to the enhancement observed from hydrostatic pressure. The phenomenology of an “activation strain”, the nonhydrostatic analogue of the activation volume, has been developed to characterize the results. Combined with the measurement of the activation volume, the measurement reported here permits us to characterize to first order the entire activation strain tensor corresponding to the transition state for solid phase epitaxy of Si(lOO). We conclude that the transition state for this process is “short and fat”; that is, the fluctuation to the transition state involves an expansion in the two in-plane directions and a contraction in the direction normal to the surface large enough to make the overall volume change negative. The symmetry of the measured activation strain tensor is inconsistent with all bulk point defect mechanisms for solid phase epitaxy. The relevance of the activation strain formalism to heteroepitaxy and vapor phase epitaxy is discussed.

1993 ◽  
Vol 321 ◽  
Author(s):  
Michael J. Aziz

ABSTRACTThe activation strain tensor describes the effect of nonhydrostatic stresses on atomic or interfacial Mobilities. It has been measured for solid phase epitaxial growth of crystalline Si (001) into amorphous Si. The activation strain concept is explained and some subtle points are discussed. Implications for proposed mechanisms of solid phase epitaxy are reviewed, and new implications for combined bulk and interfacial control are presented. Questions raised during the oral presentation are answered.


1990 ◽  
Vol 205 ◽  
Author(s):  
J. A. Roth ◽  
G. L. Olson ◽  
D. C. Jacobson ◽  
J. M. Poate ◽  
C. Kirschbaum

AbstractThis paper discusses the intrusion of H into a-Si layers during solid phase epitaxy and the effect of this H on the growth kinetics. We show that during annealing in the presence of water vapor, H is continuously generated at the oxidizing a-Si surface and diffuses into the amorphous layer, where it causes a reduction in the epitaxial growth rate. The measured variation of growth rate with the depth of the amorphous/crystal interface is correlated with the concentration of H at the interface. The diffusion coefficient for H in a-Si is determined by comparing measured depth profiles with calculated values. Hydrogen intrusion is observed even in layers annealed in vacuum and in inert gas ambients. Thin (<;5000 Åthick) a-Si layers are especially susceptible to this effect, but we show that in spite of the presence of H the activation energy for SPE derived earlier from thin-layer data is in good agreement with the intrinsic value obtained from thick, hydrogen-free layers.


1996 ◽  
Vol 441 ◽  
Author(s):  
William Barvosa-Carter ◽  
Michael J. Aziz

AbstractWe report preliminary in-situ time-resolved measurements of the effect of uniaxial stress on solid phase epitaxial growth in pure Si (001) for the case of stress applied parallel to the amorphous-crystal interface. The growth rate is reduced by the application of uniaxial compression, in agreement with previous results. Additionally, the velocity continues to decrease with time. This is consistent with interfacial roughening during growth under stress, and is supported by both reflectivity measurements and cross-sectional TEM observations. We present a new kinetically-driven interfacial roughening mechanism which is consistent with our observations.


1996 ◽  
Vol 422 ◽  
Author(s):  
A. Polman ◽  
R. Serna ◽  
J. S. Custer ◽  
M. Lohmeier

AbstractThe incorporation of erbium in silicon is studied during solid phase epitaxy (SPE) of Erimplanted amorphous Si on crystalline Si, and during Si molecular beam epitaxy (MBE). Segregation and trapping of Er is observed on Si(100), both during SPE and MBE. The trapping during SPE shows a discontinuous dependence on Er concentration, attributed to the effect of defect trap sites in the amorphous Si near the interface. Trapping during MBE is described by a continuous kinetic growth model. Above a critical Er density (which is lower for MBE than for SPE), growth instabilities occur, attributed to the formation of silicide precipitates. No segregation occurs during MBE on Si(111), attributed to the epitaxial growth of silicide precipitates.


2003 ◽  
Vol 762 ◽  
Author(s):  
M. S. Mason ◽  
C.M. Chen ◽  
H.A. Atwater

AbstractWe investigate low-temperature epitaxial growth of thin silicon films on Si [100] substrates and polycrystalline template layers formed by selective nucleation and solid phase epitaxy (SNSPE). We have grown 300 nm thick epitaxial layers at 300°C on silicon [100] substrates using a high H2:SiH4 ratio of 70:1. Transmission electron microscopy confirms that the films are epitaxial with a periodic array of stacking faults and are highly twinned after approximately 240 nm of growth. Evidence is also presented for epitaxial growth on polycrystalline SNSPE templates under the same growth conditions.


1990 ◽  
Vol 205 ◽  
Author(s):  
Guo-Quan Lu ◽  
Eric Nygren ◽  
Michael J. Aziz

AbstractWe have measured the effects of hydrostatic pressure on the solid phase epitaxial growth (SPEG) rates of undoped Ge(100) and Si(100) into their respective self-implanted amorphous phases. We found that pressure enhances the growth process in both Si and Ge, with activation volumes equal to -3.3 ± 0.3 cm3/mole for Si and -6.3 ± 0.60 cm3/mole for Ge. The results of this and other experiments are inconsistent with all bulk point-defect mechanisms, but are consistent with all interface point-defect mechanisms, proposed to date for thermal SPEG. A kinetic analysis of the Spaepen-Turnbull dangling bond mechanism shows it to be a highly plausible model for the growth process.


1984 ◽  
Vol 35 ◽  
Author(s):  
G.L. Olson

ABSTRACTRecent progress in studies of temperature dependent kinetic competition during solid phase crystallization of silicon is reviewed. Specific areas which are emphasized include: the enhancement of solid phase epitaxial growth rates by impurity-induced changes in electronic properties at the crystal/amorphous interface, the influence of impurity diffusion and precipitation in amorphous silicon on the kinetics of epitaxial growth, the effects of impurities on the kinetic competition between solid phase epitaxy and random crystallization, and the kinetics of solid phase crystallization at very high temperatures in silicon.


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