Laser Quenching of Amorphous Si from the Melt Containing Dopants

ABSTRACTThe formation of amorphous Si by the quench of a thin surface layer melted by fast UV laser irradiation has been investigated. The starting (111) surface layers were either pure or doped with As, Bi, In and Te by implantation. The asimplanted samples were recrystallized by ruby laser irradiation resulting in surface accumulation of Bi,In and Te. For the same UV irradiation condition, the amorphous layer formed in As, Bi, In or Te doped Si is about twice the thickness of the amorphous layer formed on pure Si. In the presence of the surface accumulation of Bi, In or Te, the amorphization results in an inward segregation of the dopant. For In, a very thin metal layer ˜15Å thick, is formed 150Å beneath the amorphous surface. These results show that the amorphous-liquid interfacial segregation coefficients for Bi, In or Te are less than unity and that the amorphous solidification proceeds from the surface and bottom of the liquid layer.

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Pulsed Laser Annealing of R.F.Sputtered Amorphous Si : H.Films, Doped with Arsenic

MRS Proceedings ◽

10.1557/proc-4-553 ◽

1981 ◽

Vol 4 ◽

Author(s):

E. Fogarassy ◽

R. Stuck ◽

M. Toulemonde ◽

P. Siffert ◽

J.F. Morhange ◽

...

Keyword(s):

Ruby Laser ◽

Laser Annealing ◽

Pulsed Laser ◽

Amorphous Layer ◽

High Concentration ◽

Topographic Analysis ◽

Pulsed Laser Annealing ◽

Residual Hydrogen ◽

Silicon Target ◽

Amorphous Si

Arsenic doped amorphous silicon layers have been deposited on silicon single crystals by R.F.cathodic sputtering of a silicon target in a reactive argon-hydrogen mixture, and annealed with a Q-switched Ruby laser. Topographic analysis of the irradiated layers has shown the formation of a crater, due to an evaporation effect of material which could be related to the presence of a high concentration of Ar in the amorphous layer. RBS and Raman Spectroscopy showed that the remaining layer is not recrystallised probably due to inhibition by the residual hydrogen. However, it was found that arsenic diffuses into the monocrystalline substrate by laser induced diffusion of dopant from the surface solid source, leading to the formation of good quality P-N junctions.

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Crystallization kinetics of ultrathin amorphous Si film induced by Al metal layer under thermal annealing and pulsed laser irradiation

Journal of Applied Physics ◽

10.1063/1.2654512 ◽

2007 ◽

Vol 101 (4) ◽

pp. 043518 ◽

Cited By ~ 26

Author(s):

Yung-Chiun Her ◽

Chih-Wei Chen

Keyword(s):

Laser Irradiation ◽

Thermal Annealing ◽

Crystallization Kinetics ◽

Metal Layer ◽

Pulsed Laser ◽

Amorphous Si ◽

Kinetics Of ◽

Pulsed Laser Irradiation

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Epitaxial Explosive Crystallization of Amorphous Silicon Layers Buried in a Silicon (100) and (111) Matrix

MRS Proceedings ◽

10.1557/proc-147-179 ◽

1989 ◽

Vol 147 ◽

Cited By ~ 4

Author(s):

P. A. Stolk ◽

A. Polman ◽

W. C. Sinke

Keyword(s):

Amorphous Silicon ◽

Cross Section ◽

Ruby Laser ◽

Crystallization Process ◽

Amorphous Layer ◽

High Density ◽

Time Resolved ◽

Explosive Crystallization ◽

Amorphous Si ◽

Twin Defects

Abstract420 nm thick amorphous Si layers buried in a Si (100) or Si (111) matrix, produced by 350 keV Si-implantation, were irradiated using a pulsed ruby laser. Time-resolved reflectivity measurements show that melting can be initiated buried in the samples at the crystalline-amorphous interface. Melting is immediately followed by explosive crystallization of the buried amorphous layer, which is started from the crystalline top layer. The velocity of this self-sustained crystallization process is determined to be 15.0 ± 0.5 m/s for Si (100) and 14.0 ± 0.5 m/s for Si (111). RBS and cross-section TEM reveal that epitaxially grown crystalline Si, containing a high density of twin defects, is formed in both the Si (100) and the Si (111) sample.

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Production and Properties of Amorphous Layers on Metal Substrates by Laser and Electron Beam Melting

MRS Proceedings ◽

10.1557/proc-8-497 ◽

1981 ◽

Vol 8 ◽

Cited By ~ 2

Author(s):

H.W. Bergmann ◽

B.L. Mordike

Keyword(s):

Electron Beam ◽

Laser Beam ◽

Single Crystals ◽

Electron Beam Melting ◽

Cold Working ◽

Amorphous Layer ◽

Laser Glazing ◽

Surface Layers ◽

Metal Substrates ◽

Amorphous Surface

ABSTRACTVarious techniques of laser glazing are presented. Rules are given for the choise of systems which are suitable for producing amorphous surface layers. Methods of demonstrating the existence of a truly amorphous layer are discussed. Two examples are given: I) electron beam glazing of Ni-Nb coated single crystals 2) laser beam glazing of Fe-B coated Fe-Cr-C cold working steel.

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Studies of Laser Annealed GaAs (100), (110) and (111) Surfaces

MRS Proceedings ◽

10.1557/proc-4-683 ◽

1981 ◽

Vol 4 ◽

Cited By ~ 2

Author(s):

D. M. Zehner ◽

C. W. White ◽

B. R. Appleton ◽

G. W. Ownby

Keyword(s):

Single Crystals ◽

Laser Irradiation ◽

Crystal Orientation ◽

Ruby Laser ◽

Surface Layers ◽

Auger Transition ◽

Subsurface Region ◽

Outermost Surface

ABSTRACTThe surface regions of (100), (110) and (111) oriented single crystals of GaAs have been investigated by the combine techniques of LEED, AES and RBS subsequent to their irradiation in UHV with the output of a Q–switched, ruby laser (0.15−0.8 J/cm2, 15 × 10−9 sec). Clean surfaces, as determined by AES, were obtained after Ar+ sputtering followed by laser irradiation. LEED observations indicate that the degree of disorder in the outermost surface layers remaining after irradiation depends on the crystal orientation. Although the relative intensities of Ga and As Auger transitions in spectra obtained from sputtered and laser annealed surfaces are similar, the differences in lineshape in these spectra of the M2,3M4,5M4,5 Ga Auger transition indicate that in the laser annealed case there are local regions which are nonstoichiometric. These observations are confirmed by RBS results, and this technique has been used to determine the stoichiometry and to characterize the damage in the subsurface region for all orientations.

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Furnace Anneal of A–Axis Sapphire Amorphised by Indium Ion Implantation

MRS Proceedings ◽

10.1557/proc-128-587 ◽

1988 ◽

Vol 128 ◽

Author(s):

D. K. Sood ◽

D. X. Cao

Keyword(s):

Activation Energy ◽

Ion Implantation ◽

Amorphous Phase ◽

Isothermal Annealing ◽

Amorphous Layer ◽

Surface Layers ◽

Epitaxial Regrowth ◽

Rapid Diffusion ◽

Amorphous Surface ◽

Higher Doses

ABSTRACTIndium implantation at 77°K into a–axis sapphire to peak concentrations of 6–45 mol % In produces amorphous surface layers. Isothermal annealing in Ar at temperatures between 600–900°C shows effects strongly dependent on ion dose. At lower doses <2×1016 In/cm2, the amorphous layer undergoes epitaxial regrowth as the amorphous to crystalline interface advances out towards the surface. Regrowth velocity is high in about the first half hour of the anneal. Regrowth obeys Arrhenius behaviour with an activation energy of 0.7eV for initial faster growth and 1.28eV for further anneal times. The amorphous phase transforms directly to ⊥-A12O3 without any evidence of an intermediary γ-phase. At higher doses, epitaxial regrowth is substantially retarded and rapid diffusion of In within the amorphous phase dominates.

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Quantitative energy-filtered electron diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172693 ◽

1994 ◽

Vol 52 ◽

pp. 992-993

Author(s):

R. Vincent

Keyword(s):

Electron Diffraction ◽

Inelastic Scattering ◽

Dynamic Range ◽

Electron Optics ◽

Surface Layers ◽

High Brightness ◽

Inclined Surfaces ◽

Perfect Symmetry ◽

Amorphous Surface ◽

The Ideal

Microanalysis and diffraction on a sub-nanometre scale have become practical in modern TEMs due to the high brightness of field emission sources combined with the short mean free paths associated with both elastic and inelastic scattering of incident electrons by the specimen. However, development of electron diffraction as a quantitative discipline has been limited by the absence of any generalised theory for dynamical inelastic scattering. These problems have been simplified by recent innovations, principally the introduction of spectrometers such as the Gatan imaging filter (GIF) and the Zeiss omega filter, which remove the inelastic electrons, combined with annual improvements in the speed of computer workstations and the availability of solid-state detectors with high resolution, sensitivity and dynamic range.Comparison of experimental data with dynamical calculations imposes stringent requirements on the specimen and the electron optics, even when the inelastic component has been removed. For example, no experimental CBED pattern ever has perfect symmetry, departures from the ideal being attributable to residual strain, thickness averaging, inclined surfaces, incomplete cells and amorphous surface layers.

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