Ion Beam Induced Amorphization and Crystallization Processes in Silicon and GaAs

1986 ◽  
Vol 74 ◽  
Author(s):  
R. G. Elliman ◽  
J. S. Williams ◽  
S. T. Johnson ◽  
E. Nygren
Keyword(s):  
Crystal Growth ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Amorphous Layer ◽  
Poor Quality ◽  
Layer By Layer ◽  
Epitaxial Crystallization ◽  
Non Linear ◽  
Thickness Layer

AbstractThin amorphous layers in crystalline Si and GaAs substates have been irradiated at selected temperatures with 1.5 MeV Ne+ ions to induce either epitaxial crystallization or amorphization. In Si, such irradiation can induce complete epitaxial crystallization of a 1000 A surface amorphous layer for temperatures typically >200°C whereas, at significantly lower temperatures, layer-by-layer amorphization results. Although epitaxial crystallization can also be stimulated in GaAs by ion irradiation at temperatures >65°C, the process is non-linear with ion dose and results in poor quality crystal growth for amorphous layers greater than a few hundred Angstroms in thickness. Layer-by-layer amorphization has not been observed in GaAs.

Ion-Beam Induced Epitaxial Crystallization of NiSi2 And CoSi2

1989 ◽  
Vol 157 ◽  
Author(s):  
M.C. Ridgway ◽  
R.G. Elliman ◽  
J.S. Williams
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Activation Energies ◽  
Layer By Layer ◽  
Surface Layers ◽  
Epitaxial Crystallization ◽  
Si Substrates ◽  
Amorphous Surface

ABSTRACTIon—beam induced epitaxial crystallization (IBIEC) of amorphous N1Si2 and CoSi2 layers is demonstrated. Epitaxial metal suicide layers on (111) Si substrates were implanted with 40 keV Si ions to form amorphous surface layers. IBIEC of amorphous NiSi2 and CoSi2 layers was induced at 13—74°C with 1.5 MeV Ne ion irradiation and proceeded in a layer—by—layer manner from the original amorphous/crystalline interface with activation energies of 0.26 ± 0.07 and 0.21 ± 0.06 eV for N1Si2 and CoSi2, respectively.

Ion Beam Induced Epitaxial Crystallization of Single Crystalline 6H-SiC

1993 ◽  
Vol 321 ◽  
Author(s):  
V. Heera ◽  
R. Kögler ◽  
W. Skorupa ◽  
E. Glaser
Keyword(s):  
Surface Layer ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Amorphous Layer ◽  
Single Crystalline ◽  
Epitaxial Crystallization ◽  
Amorphous Surface ◽  
20 Nm ◽  
First Time

ABSTRACTFor the first time, ion beam induced epitaxial crystallization (IBIEC) has been found in SiC. The effect of 300 keV Si+ irradiation through an amorphous surface layer in single crystalline 6H-SiC at 477+5°C has been investigated by RBS/C and XTEM. A shrinkage of the amorphous layer was found after ion irradiation at this temperature which is caused by both an ion dose independent thermal regrowth of about 20 nm and an additional ion beam induced epitaxial crystallization with a rate of about 1.5 nm/ 1016 cm−2.

Ion Beam Induced Epitaxial Crystallization of Single Crystalline 6H-SiC

1993 ◽  
Vol 316 ◽  
Author(s):  
V. Heera ◽  
R. Kögler ◽  
W. Skorupa ◽  
E. Glaser
Keyword(s):  
Surface Layer ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Amorphous Layer ◽  
Single Crystalline ◽  
Epitaxial Crystallization ◽  
Amorphous Surface ◽  
20 Nm ◽  
First Time

ABSTRACTFor the first time, ion beam induced epitaxial crystallization (IBIEC) has been found in SiC. The effect of 300 keV Si+ irradiation through an amorphous surface layer in single crystalline 6H-SiC at 477±5°C has been investigated by RBS/C and XTEM. A shrinkage of the amorphous layer was found after ion irradiation at this temperature which is caused by both an ion dose independent thermal regrowth of about 20 nm and an additional ion beam induced epitaxial crystallization with a rate of about 1.5 nm/ 1016 cm-2.

Epitaxial Crystallization of Amorphous Silicon Layers under Ion Irradiation: Orientation Dependence

1987 ◽  
Vol 93 ◽  
Author(s):  
D. M. Maher ◽  
R. G. Elliman ◽  
J. Linnros ◽  
J. S. Williams ◽  
R. V. Knoell ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Solid Phase ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Orientation Dependence ◽  
Epitaxial Crystallization ◽  
Beam Experiment ◽  
Interfacial Defects ◽  
Behavior Supports ◽  
Orientation Dependency

ABSTRACTIon-beam induced epitaxial crystallization of thin amorphous silicon layers at {100} and {110} crystalline/amorphous interfaces exhibits no orientation dependencies, whereas at a {111} crystalline/amorphous interface a weak orientation dependency relative to thermal-induced epitaxial crystallization is observed. This behavior supports an interpretation in which the thermal crystallization process is dominated by the need to form interfacial defects and/or growth sites and in the ion-beam experiment this formation process ocurrs athermally. It is thought that the observed orientation dependent regrowth on a {111} substrate relative to a {100} (or {110}) substrate is associated with the special correlated atomic sequencing which is believed to control solid-phase epitaxial crystallization at a {111) crystalline/amorphous interface.

Roughening of Au(111) Surfaces During Ion Beam Erosion: A Scanning Tunneling Microscope and X-Ray Diffraction Study

1999 ◽  
Vol 570 ◽  
Author(s):  
A. Judy ◽  
M.V. Ramana Murty ◽  
E. Butler ◽  
J. Pomeroy ◽  
B.H. Cooper ◽  
...  
Keyword(s):  
Scanning Tunneling Microscope ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Normal Incidence ◽  
Scanning Tunneling ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Tunneling Microscopy ◽  
X Ray ◽  
Glancing Angle

ABSTRACTUsing Scanning Tunneling Microscopy(STM) and X-ray diffraction(XRD), we have studied the development of surface roughness on Au(111) during 500eV Ar+ ion irradiation at different angles. During normal incidence erosion the surface roughens and pattern formation occurs. The surface morphology is a mixture of mounds and pits superimposed onto a larger structure of channels and valleys. The characteristic spacing between features grows with a power law behavior t27, where t is the amount of time the sample was irradiated, in agreement with previous measurements[l]. At glancing angles, erosion proceeds smoothly, but not in layer-by-layer fashion. Finally, a combination of glancing angle and normal incidence erosion is used to create a rippled morphology

The Competition between Ion Beam Induced Epitaxial Crystallization and Amorphization in Silicon: The Role of the Divacancy

1986 ◽  
Vol 74 ◽  
Author(s):  
J. Linnros ◽  
R. G. Elliman ◽  
W. L. Brown
Keyword(s):  
Activation Energy ◽  
Dose Rate ◽  
Dynamic Equilibrium ◽  
Ion Beam ◽  
Amorphous Layer ◽  
Linear Displacement ◽  
Epitaxial Crystallization ◽  
Critical Dose ◽  
Ion Species

AbstractThe transition from ion induced epitaxial crystallization to planar amorphization of a preexisting amorphous layer in silicon has been investigated. The conditions for dynamic equilibrium at the transition were determined for different ion species as a function of dose rate and temperature. The critical dose rate for equilibrium varies exponentially with 1/T, exhibiting an activation energy of ∼1.2 eV. Furthermore, for different ions, the critical dose rate is inversely proportional to the square of the linear displacement density created by individual ions. This second order defect production process and the activation energy, which is characteristic of divacancy dissociation, suggest that the accumulation of divacancies at the amorphous/crystalline interface controls the balance between crystallization and amorphization.

The Kinetics and Microstructure of Ion Beam Induced Crystallisation of Silicon

1985 ◽  
Vol 45 ◽  
Author(s):  
J.S. Williams ◽  
W.L. Brown ◽  
R. G. Elliman ◽  
R. V. Knoell ◽  
D.M. Maher ◽  
...  
Keyword(s):  
Activation Energy ◽  
Crystal Growth ◽  
Growth Kinetics ◽  
Temperature Regime ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Nucleation Sites ◽  
Higher Temperature

ABSTRACTThis paper reviews recent detailed investigations into the crystal growth kinetics and the microstructure of ion-beam-stimulated epitaxial crystallisation of silicon. Beam-induced crystallisation at temperatures between 200-400°C is found to be characterised by an activation energy of 0.24eV. Furthermore, in this temperature regime, crystal growth on (100) silicon is found to be free of extended defects except for a sharp hand of dislocation loops centred about the range of the ions employed to stimulate crystallisation. A higher temperature regime (>400°C) is observed in which the growth kinetics are less well defined but appear to be associated with an apparent activation energy of >0.5eV. In this regime, extended defects are observed to extend from the ion range to the surface. Results are presented which strongly suggest that nuclear energy deposition precisely at the amorphous-crystalline interface is responsible for crystallisation under ion irradiation. It is argued that the major fraction (2.4eV) of the thermal-only activation energy for epitaxial crystallisation of silicon is likely to be associated with the formation of nucleation sites for growth, a step which is achieved athermally under ion irradiation. In addition, the growth rate per unit ion fluence is found to be independent of substrate orientation at temperatures <450°C and independent of doping concentration for temperatures <400°C. These results are consistent with our proposed model for beam-induced crystallisation.

Evolution of Semiconductor Thin Film and Surface Microstructure During Ion Bombardment

1990 ◽  
Vol 202 ◽  
Author(s):  
H. A. Atwater
Keyword(s):  
Thin Films ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Amorphous Layer ◽  
Misfit Strain ◽  
Crystal Nucleation ◽  
Microstructural Development ◽  
Complete Suppression ◽  
Semiconductor Films ◽  
Interface Motion

ABSTRACTDefects created by ion irradiation can enable new modes of microstructural development at interfaces and surfaces in semiconductor thin films. Two examples are described. First, novel kinetic paths for microstructural evolution via MeV ion beam modification of amorphous-crystal interface motion in Si are discussed. At intermediate temperatures, amorphous layer formation is initiated at interfaces such as surfaces and grain boundaries in polycrystalline Si. Irradiation at higher temperatures during the early stages of Si crystallization leads to a significant enhancement of the crystal nucleation rate, while nearly complete suppression of crystal nucleation during crystal growth can be achieved by a cyclic irradiation-induced amorphization and thermal growth process. Second, a new development in misfit strain accommodation in epitaxial semiconductor films is described in which ion-induced injection of point defect complexes can produce coherent, uniformly strained epitaxial thin films. Measurement of strain in epitaxial films can be used to distinguish between surface and sub-surface atomic displacements generated by a low energy ion beam.

Investigation of NEV Au++ implanted silicon

1990 ◽  
Vol 48 (4) ◽  
pp. 654-655
Author(s):  
T.L. Alford ◽  
N.D. Theodore ◽  
J.W. Mayer ◽  
C.B. Carter ◽  
N.W. Cheung
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Amorphous Layer ◽  
Copper Sample ◽  
Extended Defects ◽  
Ion Beam Irradiation ◽  
Beam Path ◽  
Significant Difference ◽  
Different Types ◽  
Lattice Damage

There has recently been increasing use of MeV ion beams for materials modification. When compared to more common lower, keV-energy implantation, MeV-ion irradiation has a broader variation in the type of damage along the ion path. This is because of the more significant difference between damage and range distributions in the case of MeV implants as opposed to keV implants. Previous works showed that MeV-implanted Si-ions react differently with various types of lattice damage in silicon; interactions range from simple point-defect annihilation to the formation of extended defects. Earlier investigations of Au implanted into previously amorphized silicon have observed Au segregation as a result of its being expelled from the recrystallizing amorphous layer during ion-beam irradiation. In this study, the interaction of MeV Au++ atoms with the different types of damage produced along the MeV-ion beam path is investigated.Silicon (100) single crystal wafers were given a HF dip and were then mounted on a copper sample stage; the stage functions as a heat-sink. The stage together with the specimen was then placed in a Tandem ion-implanter. The specimens were implanted with gold; implant-energies varied from 1.8 - 4.4 MeV and fluences ranged between 0.1 - 10×1016 Au++/cm2.

Segregation and Trapping of Gold During Ion-Induced Crystallization of Amorphous Si

1988 ◽  
Vol 100 ◽  
Author(s):  
J. M. Poate ◽  
J. Linnros ◽  
F. Priolo ◽  
D. C. Jacobson ◽  
J. L. Batstone ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Ion Irradiation ◽  
Equilibrium Concentration ◽  
Segregation Coefficient ◽  
Epitaxial Crystallization ◽  
Temperature Range ◽  
Interfacial Segregation ◽  
Amorphous Si ◽  
Induced Crystallization ◽  
Crystal Interface

ABSTRACTA novel regime of crystal growth and segregation has been observed. Amorphous Si layers were uniformly doped with Au and epitaxial crystallization was induced in the temperature range 250–420°C using 2.5 MeV Ar ion irradiation. The Au segregation at the amorphous/crystal interface is analogous to behavior at liquid/solid interfaces except that the interfacial segregation coefficient of 0.007 at 320°C is independent of velocity between 0.6 and 6A/sec. This process results in the trapping of Au in crystalline Si at concentrations some ten orders of magnitude in excess of equilibrium concentration.

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