Impurity Redistribution In Ion Implanted Si After Picosecond Nd Laser Pulse Irradiation

1982 ◽  
Vol 13 ◽  
Author(s):  
S.U. Campisano ◽  
P. Baeri ◽  
E. Rimini ◽  
G. Russo ◽  
A.M. Malvezzi
Keyword(s):  
Energy Density ◽  
Laser Pulse ◽  
Sample Surface ◽  
Relaxation Processes ◽  
Impurity Segregation ◽  
Carrier Temperature ◽  
Crystal Transition ◽  
Channeling Effect ◽  
Melt Duration ◽  
Impurity Redistribution

AbstractImpurity redistribution in Bi-implanted Si and in As-implanted Si has been investigated after irradiation with 25 ps Nd(λ=l.06 μm) laser pulse in the energy range 0.1–1.5 J/cm2 . Channeling effect in combination with 2.0 MeV He+ backscattering in glancing detection has been used to characterize the epitaxial crystallization, the impurity location and its depth distribution. The amorphous to single crystal transition occurs at an energy density of about 0.4 J/cm 2 . Bi atoms are located after crystallization in substitutional lattice sites for the in depth part of the distribution. Part of the Bi atoms accumulated at the sample surface and the amount of segregation increases with the pulse energy density and depends on the substrate orientation. A computer model has been also developed to calculate several parameters of interest, as the melt threshold,the melt duration, the carrier temperature etc including a detailed description of the absorption and of the energy relaxation processes. The calculations indicate that the simple thermal description accounts quantitatively for the experimental data on melt duration and impurity segregation.

Laser Encapsulation of Metallic Films in SiO2

1995 ◽  
Vol 397 ◽  
Author(s):  
A. J. Pedraza ◽  
S. Cao ◽  
D. H. Lowndes ◽  
L. F. Allard
Keyword(s):  
Energy Density ◽  
Laser Pulse ◽  
Laser Energy ◽  
Substrate Material ◽  
Laser Energy Density ◽  
Cross Sectional ◽  
Metallic Particles ◽  
Transmission Electron ◽  
Encapsulation Process ◽  
Deposited Film

ABSTRACTThin films of gold, copper and iron deposited on silica were driven into the substrate by a laser pulse. This transport takes place only when the irradiation is performed at a laser energy density of 0.7 J/cm2 or lower. Cross sectional transmission electron microscopy (TEM) of the irradiated specimens reveals two distinctive stages in the encapsulation process. In the first, the film melts and clusters into small particles and in the second one the particles are driven into the substrate by the laser pulse. The particle size of encapsulated metal varies from 5 to 50 nm. Selected area diffraction of the large particles and lattice fringe images of the smaller particles reveal pure metals, e.g., gold, copper or iron. Titanium films laser irradiated are not encapsulated in silica; instead, these films react with silica forming an amorphous compound. Apparently, one of the conditions required for encapsulation is that the metal should not react with the substrate material. On subsequent irradiation at a laser energy density of 1.5 J/cm2, ablation of silica partially exposes the metallic particles. Strong bonding between a new film deposited after irradiation and the substrate is obtained because these particles anchor the freshly deposited film. Anchoring is clearly revealed by cross sectional TEM. The mechanisms of encapsulation are discussed using results from TEM and adhesion testing.

Electrophysical and photoelectrical properties of epitaxial films of Hg1−xCdxTe (x ≈ 0.2) after laser treatment

1992 ◽  
Vol 70 (5) ◽  
pp. 357-360 ◽  
Author(s):  
M. Kuźma ◽  
C. Abeynayake ◽  
E. M. Sheregii ◽  
Y. O. Ugrin ◽  
I. S. Virt
Keyword(s):  
Energy Density ◽  
Laser Pulse ◽  
Laser Treatment ◽  
Cluster Model ◽  
Spectral Dependence ◽  
Laser Annealing ◽  
Epitaxial Films ◽  
Photoelectrical Properties ◽  
Before And After ◽  
Nonequilibrium Carriers

Changes in the electrophysical and photoelectrical properties of epitaxial films of Hg1−xCdxTe (x ≈ 0.2) due to laser annealing are studied. Experimental fits for the dependence of the resistance of the film to the energy density of the laser pulse, to the time, as well as to the temperature are obtained before and after laser annealing. Further, changes in the lifetime of minority nonequilibrium carriers of charge and the spectral dependence of the photoconductivity because of laser annealing are shown. Experimental results are interpreted on the basis of the two cluster model for electro- and photoconductivity.

scholarly journals Experimental energy-density flux characterization of ultrashort laser pulse filaments

2009 ◽  
Vol 17 (10) ◽  
pp. 8193 ◽  
Author(s):  
Daniele Faccio ◽  
Antonio Lotti ◽  
Aidas Matijosius ◽  
Francesca Bragheri ◽  
Vittorio Degiorgio ◽  
...  
Keyword(s):  
Energy Density ◽  
Laser Pulse ◽  
Ultrashort Laser Pulse ◽  
Experimental Energy ◽  
Ultrashort Laser

The effects of the atmosphere on the surface modification of alumina by pulsed-laser-irradiation

1997 ◽  
Vol 12 (7) ◽  
pp. 1747-1754 ◽  
Author(s):  
Siqi Cao ◽  
A. J. Pedraza ◽  
L. F. Allard ◽  
D. H. Lowndes
Keyword(s):  
Energy Density ◽  
Laser Pulse ◽  
Thin Layer ◽  
Amorphous Phase ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Near Surface ◽  
Metallic Particles ◽  
Cellular Microstructure

A near-surface thin layer is melted when alumina is pulsed-laser-irradiated in an Ar–4% H2 atmosphere or in air. A thin layer of amorphous phase forms when the substrates are irradiated in Ar–4% H2 at 1 to 1.3 J/cm2 with multiple laser pulses. Amorphous phase is also found in samples laser-irradiated in air and oxygen. After a laser pulse at an energy density of 1.6 J/cm2 or higher the melt solidifies epitaxially from the unmelted substrate with a cellular microstructure. There is a decrease in the cooling rate of the melt as the laser energy density is increased because more heat must be dissipated. The amorphous phase forms when the heat input due to the laser pulse produces a superheated melt that cools down sufficiently fast to avoid crystallization. Very small particles of aluminum in the laser-melted and subsequently solidified layer are observed only in samples laser-irradiated in an Ar–4% H2 atmosphere. In this reducing atmosphere, the alumina is possibly reduced to metallic aluminum which is mixed into the melt by the turbulence provoked by the laser pulses. The effects of these metallic particles on copper deposition when the irradiated substrates are immersed in an electroless bath are discussed.

Influence of Laser Radiation on Movement of Dislocations in Silicon Single Crystals

2021 ◽  
Vol 410 ◽  
pp. 742-747
Author(s):  
Alexander A. Solovyev ◽  
Vladislav V. Rybin
Keyword(s):  
Laser Radiation ◽  
Energy Density ◽  
Laser Pulse ◽  
Pulse Energy ◽  
Acoustic Waves ◽  
Surface Defects ◽  
Linear Defects ◽  
Semiconductor Crystals ◽  
Micro Cracks ◽  
P Type

The behavior of linear defects in n-and p-type silicon, generated by laser radiation is studied for pulse energy density 417 – 1083 mJ/cm2. The features of the nondestructive and destructive effects of the laser pulse on the surface defects formation of the semiconductor crystals are revealed. The formation and movement of dislocations in the crater region and the development of micro cracks, accompanied by acoustic waves are revealed.

Bilayer Structures Obtained by Pulsed Laser Quenching of Binary Systems

1988 ◽  
Vol 100 ◽  
Author(s):  
P. Baeri ◽  
G. Foti ◽  
M. G. Grimaldi ◽  
F. Priolo ◽  
R. Reitano ◽  
...  
Keyword(s):  
Energy Density ◽  
Laser Pulse ◽  
Binary Systems ◽  
Pulsed Laser ◽  
Epitaxial Layers ◽  
Silicon Substrates ◽  
High Fluence ◽  
Laser Quenching ◽  
Ion Implanted

ABSTRACTNiSi and Ni2Si layers on silicon substrates as well as high fluence Si(As) ion implanted layers,have been rapidly melted by 30 ns Nd laser pulse irradiation.The energy density ranged between 0.4 and 1.2 J/cm2. Bilayer structures have been observed when the energy density has been chosen properly.Buried epitaxial layers together with an amorphous or a policrystalline layer on top,have been detected by RBS and TEM measurements.

Strain Relaxation of Ion-implanted Strained Silicon on Relaxed SiGe

2004 ◽  
Vol 810 ◽  
Author(s):  
R. T. Crosby ◽  
K. S. Jones ◽  
M. E. Law ◽  
A. F. Saavedra ◽  
J. L. Hansen ◽  
...  
Keyword(s):  
Strain Relaxation ◽  
Sample Surface ◽  
Amorphous Layer ◽  
Strained Silicon ◽  
Relaxation Processes ◽  
X Ray Diffraction ◽  
Strained Si ◽  
Cross Sectional ◽  
Molecular Beam Epitaxial ◽  
Transmission Electron

ABSTRACTThe relaxation processes of strained silicon films on silicon-rich relaxed SiGe alloys have been studied. Experimental structures were generated via Molecular Beam Epitaxial (MBE) growth techniques and contain a strained silicon capping layer of approximately 50 nm. The relaxed SiGe alloy compositions range from 0 to 30 atomic% germanium. Samples received two distinct types of silicon implants. A 12 keV Si+ implant at a dose of 1×1015 atoms/cm2 was used to generate an amorphous layer strictly confined within the strained Si cap. An alternate 60 keV Si+ implant at a dose of 1×1015 atoms/cm2 was employed to create a continuous amorphous layer extending from the sample surface to a position 50 nm into the bulk SiGe material. The strain relaxation and regrowth processes are quantified through High Resolution X-Ray Diffraction (HRXRD) rocking curves and Cross-sectional Transmission Electron Microscopy (XTEM). The role of injected silicon interstitials upon the strain relaxation processes at the Si/SiGe interface after annealing at 600°C is investigated.

Femtosecond and Nanosecond Laser Pulse Crystallization of Thin a-Si:H Films on Non-Refractory Glass Substrates

2007 ◽  
Vol 131-133 ◽  
pp. 479-484 ◽  
Author(s):  
Vladimir A. Volodin ◽  
M.D. Efremov ◽  
G.A. Kachurin ◽  
S.A. Kochubei ◽  
A.G. Cherkov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Energy Density ◽  
Laser Pulse ◽  
Raman Scattering ◽  
Pulse Energy ◽  
Laser Wavelength ◽  
Nanosecond Laser ◽  
Glass Substrates ◽  
Pulse Energy Density ◽  
Krf Laser

Thin (90 nm) a-Si:H films on Corning 7059 glass substrates have been crystallized by 120 fs pulses of Ti:sapphire and nanosecond pulse XeCl and KrF excimer lasers. Initial films were deposited using low-temperature plasma enhanced deposition technique. The structural properties of the films were characterized using the spectroscopy of Raman scattering, excited by the argon laser (line 514.5 nm) and using electron microscopy. For the femtosecond pulse treatments the ablation threshold was found to be some more than 65 mJ/cm2. When pulse energy density was lower than ~30 mJ/cm2 no structural changes were observed. In optimal regimes the films were found to be fully crystallized with needle grain structure, according to the Raman scattering and electron microscopy data. Estimates show the pulse energy density was lower than the Si melting threshold, so non-thermal “explosive” impacts may play some role. The main result in nanosecond XeCl and KrF laser pulse crystallization is the narrower window between beginning of crystallization and ablation for KrF laser (wavelength 248 nm) than for the XeCl laser (wavelength 308 nm). So, the possibility of the femtosecond and nanosecond laser pulses to crystallize a-Si films on non refractory glass substrates was shown. The results obtained are of great importance for manufacturing of polycrystalline silicon layers on non-refractory large-scale substrates for giant microelectronics.

Impurity redistribution in Bi‐implanted Si after nanosecond and picosecond Nd laser pulse irradiation

1982 ◽  
Vol 41 (5) ◽  
pp. 456-458 ◽  
Author(s):  
S. U. Campisano ◽  
P. Baeri ◽  
E. Rimini ◽  
A. M. Malvezzi ◽  
G. Russo
Keyword(s):  
Laser Pulse ◽  
Pulse Irradiation ◽  
Impurity Redistribution
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