Solid-Phase Epitaxy - Role of Point Defects in Amorphous Solids

1993 ◽  
Vol 319 ◽  
Author(s):  
T.K. Chaki
Keyword(s):  
Epitaxial Growth ◽  
Point Defects ◽  
Solid Phase ◽  
Ion Irradiation ◽  
Amorphous Solid ◽  
Amorphous Layer ◽  
Amorphous Solids ◽  
Solid Phase Epitaxy ◽  
Self Diffusion

AbstractA model of solid-phase epitaxial growth (SPEG), explaining enhancing effects of ion-irradiation and dopants, is presented. The crystallization is by the adjustment of atomic positions in the amorphous side of the crystalline/amorphous (c-a) interface due to self-diffusion in the amorphous solid, assisted by a freeenergy decrease associated with the transformation from the amorphous (a) to crystalline (c) phase. Irradiation and electrically active dopants increase the selfdiffusivity of a-phase by generating point defects in the amorphous layer and thus enhance crystallization. An expression for the velocity of epitaxial growth is derived. The low activation energy of ion-induced SPEG is due to recombination of point defects in the a-phase.

Mechanism of Stress-Enhanced Solid-Phase Epitaxy

1991 ◽  
Vol 237 ◽  
Author(s):  
T. K. Chaki
Keyword(s):  
Hydrostatic Pressure ◽  
Point Defects ◽  
Solid Phase ◽  
Amorphous Solid ◽  
Amorphous Layer ◽  
Crystalline Phases ◽  
Self Diffusion ◽  
Bending Stresses ◽  
Enhanced Mobility ◽  
The Difference

ABSTRACTEnhancement of solid-phase epitaxial growth (SPEG) due to hydrostatic pressures and bending stresses is explained by stress-enhanced mobility of point defects in the amorphous solid. The crystallization is by the adjustment of atomic positions in the vicinity of the crystallization/amorphous (c-a) interface due to self-diffusion in the amorphous phase, assisted by a free energy decrease equal to the difference in free energies between the amorphous and crystalline phases. Due to a mismatch in the bulk moduli between the amorphous and crystalline phases, the application of a hydrostatic pressure can develop tensile stresses in the amorphous layer near the c-a interface. Non-hydrostatic stresses in the amorphous layer enhance the mobility of point defects in the amorphous layer and, therefore, an enhancement of the SPEG rate. In the cases of both hydrostatic pressure and bending, the enhancement occurs in the tensile side, indicating that vacancy-like mechanism is predominant in SPEG.

Process and Mechanism of CoSi2/Si Solid Phase Epitaxy by Multilayer Reaction

1999 ◽  
Vol 580 ◽  
Author(s):  
Bing-Zong Li ◽  
Xin-Ping Qu ◽  
Guo-Ping Ru ◽  
Ning Wang ◽  
Paul Chu
Keyword(s):  
Epitaxial Growth ◽  
Solid Phase ◽  
Amorphous Layer ◽  
Solid Phase Epitaxy ◽  
Initial Stage ◽  
Vital Effect ◽  
Amorphous Si ◽  
Kinetics Of ◽  
State Amorphization

AbstractA multilayer structure of Co/a-Si/Ti/Si(100) together with Co/Ti/Si(100) is applied to investigate the process and mechanism of CoSi2 epitaxial growth on a Si(100) substrate. The experimental results show that by adding an amorphous Si layer with a certain thickness, the epitaxial quality of CoSi2 is significantly improved. A multi-element amorphous layer is formed by a solid state amorphization reaction at the initial stage of the multilayer reaction. This layer acts as a diffusion barrier, which controls the atomic interdiffusion of Co and Si and limits the supply of Co atoms. It has a vital effect on the multilayer reaction kinetics, and the epitaxial growth of CoSi2 on Si. The kinetics of the CoSi2 growth process from multilayer reactions is investigated.

Epitaxial growth versus nucleation in amorphous Si doped with Cu and Ag

1993 ◽  
Vol 8 (4) ◽  
pp. 820-829 ◽  
Author(s):  
J.S. Custer ◽  
Michael O. Thompson ◽  
D.J. Eaglesham ◽  
D.C. Jacobson ◽  
J.M. Poate
Keyword(s):  
Epitaxial Growth ◽  
Solid Phase ◽  
Intrinsic Rate ◽  
Amorphous Layer ◽  
Solubility Limit ◽  
Solid Phase Epitaxy ◽  
Metal Impurities ◽  
Random Nucleation ◽  
Si Doped ◽  
Amorphous Si

The competition between solid phase epitaxy and random nucleation in amorphous Si implanted with Cu and Ag has been studied. At low metal concentrations, solid phase epitaxy proceeds with slight deviations from the intrinsic rate, with the impurity segregated and evenly distributed in the amorphous layer. At an impurity concentration of 0.12 at.%, rapid nucleation occurs, transforming the remaining layer into polycrystalline Si. The nucleation rate is ≥108 the intrinsic homogeneous rate. The effects of the metals on epitaxy scale with the amount of metal–Si interaction. Nucleation appears to occur when the metal impurities exceed their absolute solubility limit and begin to phase separate.

New DSPEG Approach to Improvement of SOS Using Low Dose Self-Implantations

1986 ◽  
Vol 74 ◽  
Author(s):  
Eliezer Dovid Richmond ◽  
Alvin R. Knudson ◽  
H. Kawayoshi
Keyword(s):  
Epitaxial Growth ◽  
Low Dose ◽  
Solid Phase ◽  
Silicon Layer ◽  
Amorphous Layer ◽  
New Approach ◽  
Ion Damage ◽  
Defect Elimination

AbstractA new approach is proposed for the material improvement of silicon-on-sapphire (SOS). This approach utilizes the phenomena that the defect elimination throughout the silicon layer depends on both the deep and shallow self-implantations of the double solid phase epitaxial growth (DSPEG) technique for SOS material improvement. The new aspects of this approach are that the deep implantation does not form an amorphous layer, and therefore the ion damage to the substrate is minimized eliminating Al autodoping of the silicon layer.

Self Diffusion in SiC: the Role of Intrinsic Point Defects

2001 ◽  
Vol 353-356 ◽  
pp. 323-326 ◽  
Author(s):  
Alexander Mattausch ◽  
M. Bockstedte ◽  
Oleg Pankratov
Keyword(s):  
Point Defects ◽  
Intrinsic Point Defects ◽  
Self Diffusion

The Effect of Hydrogen on the Kinetics of Solid Phase Epitaxy in Amorphous Silicon

1990 ◽  
Vol 205 ◽  
Author(s):  
J. A. Roth ◽  
G. L. Olson ◽  
D. C. Jacobson ◽  
J. M. Poate ◽  
C. Kirschbaum
Keyword(s):  
Growth Rate ◽  
Solid Phase ◽  
Intrinsic Value ◽  
Amorphous Layer ◽  
Inert Gas ◽  
Solid Phase Epitaxy ◽  
Depth Profiles ◽  
Kinetics Of ◽  
Crystal Interface ◽  
Good Agreement

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.

Solid phase epitaxy of implantation-induced amorphous layer in (11̄00)- and (112̄0)-oriented 6H-SiC

2001 ◽  
Vol 89 (3) ◽  
pp. 1986 ◽  
Author(s):  
Masataka Satoh ◽  
Yuuki Nakaike ◽  
Tomonori Nakamura
Keyword(s):  
Solid Phase ◽  
Amorphous Layer ◽  
Solid Phase Epitaxy

Irradiation-Induced Grain Growth: Role of Dislocations

1989 ◽  
Vol 157 ◽  
Author(s):  
Charles W. Allen ◽  
Lynn E. Rehn
Keyword(s):  
Grain Growth ◽  
Point Defects ◽  
Ion Irradiation ◽  
Boundary Migration ◽  
Dislocation Motion ◽  
Boundary Structure ◽  
Thermal Growth ◽  
Growth Phenomenon

ABSTRACTExisting theories of irradiation-induced grain growth assume that growth occurs by the boundary migration mechanism commonly observed for thermal growth and that it is only the point defects generated si boundaries during the irradiation which are responsible for boundary migration. In contrast, in situ observations during ion irradiation of Au films at temperatures less than 20 K even have clearly demonstrated that growth occurs both by boundary migration and by grain coalescence. Here we present further evidence for the latter. Furthermore, the substantial defect cluster activity observed during irradiation suggests that dislocations play a significant role in the growth phenomenon. Here, we also demonstrate qualitatively that glide of such dislocations to or “through” a boundary can produce essentially the same effect on boundary position or structure that the original point defects would have had if they had migrated individually to or through the boundary. Via dislocation motion, point defects originating far from a boundary may induce boundary migration or boundary structure change, and hence, grain growth.

Epitaxy and Nucleation in Cu and Ag Doped Amorphous Si

1990 ◽  
Vol 205 ◽  
Author(s):  
J. S. Custer ◽  
Michael O. Thompson ◽  
D. J. Eaglesham ◽  
D. C. Jacobson ◽  
J. M. Poate ◽  
...  
Keyword(s):  
Solid Phase ◽  
Amorphous Material ◽  
Intrinsic Rate ◽  
Amorphous Layer ◽  
Solid Phase Epitaxy ◽  
Small Deviations ◽  
Random Nucleation ◽  
Low Concentrations ◽  
Critical Metal ◽  
Amorphous Si

AbstractThe competition between solid phase epitaxy and random nucleation during thermal annealing of amorphous Si implanted with the fast diffusers Cu and Ag has been studied. For low concentrations of these impurities, solid phase epitaxy proceeds with small deviations from the intrinsic rate and with the impurity remaining in the shrinking amorphous layer. At a critical metal concentration in the amorphous layer of ∼ 0.12 at.% rapid random nucleation occurs, halting epitaxy and transforming the remaining amorphous material to polycrystalline Si via grain growth. The nucleation rate is at least 8 orders of magnitude greater than the intrinsic homogeneous rate. At higher Cu concentrations nucleation is observed below the temperature needed for epitaxy (400°C). This nucleation, clearly caused by the presence of Cu or Ag in the layer, may be induced by the impurities exceeding the absolute stability concentration and starting to phase separate, leading to enhanced crystal Si nucleation in the metal rich regions.

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