Dopant Distribution and Electrical Characteristics of Boron-Doped Si1−xGex/Si p+/N Heterojunction Diodes Produced by Gas Immersion Laser Doping (GILD) / Pulsed Laser-Induced Epitaxy (PLIE)

1992 ◽  
Vol 263 ◽  
Author(s):  
K.-Josef Kramer ◽  
E. Ishida ◽  
S. Talwar ◽  
K. H. Weiner ◽  
P. G. Carey ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Layer Growth ◽  
Molten Layer ◽  
Energy Fluence ◽  
Laser Doping ◽  
Hall Effect Measurements ◽  
Heterojunction Diodes

ABSTRACTPulsed Laser-Induced Epitaxy / Gas Immersion Laser Doping is used to create borondoped heteroepitaxial p+/N Si1−xGex/Si layers and diodes. Borontriflouride is used as the gaseous dopant source. The mechanisms of heteroepitaxial layer growth of Si1−xGex using PLIE are described and impurity incorporation from the gas phase into the molten layer is investigated. Compared to other heteroepitaxial techniques, very different process parameters determine the growth. The energy fluence of the pulsed laser beam determines the melt depth and thus the layer thickness; Si and Ge intermix in the liquid phase, the diffusion of B dopant also depends on its diffusivity in the liquid phase. Boron incorporation is investigated as a function of laser energy fluence and number of laser pulses using SIMS and Hall-effect measurements. The dose of incorporated dopant is on the order of 1013cm−2 per pulse. The obtained boron profiles are flat except for a pile-up at the interface which is due to segregation. Boron and Germanium distribution are compared to turn-on voltage shifts obtained from p+/N Si1-xGex/Si heterojunction diodes fabricated with the technique. A two-step Laser process to independently control metallurgical and electrical junction depth of the diodes has been implemented. The selective nature of the epitaxial process is emphasized.

Optimization of Laser Energy Fluence in Pulsed Laser Deposition of ZnO on Al2O3(0001)

2000 ◽  
Vol 648 ◽  
Author(s):  
W. Yang ◽  
R. D. Vispute ◽  
S. Choopun ◽  
R. P. Sharma ◽  
H. Shen ◽  
...  
Keyword(s):  
Laser Fluence ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Optical Quality ◽  
Layer Growth ◽  
Zno Films ◽  
Energy Fluence ◽  
Ion Channeling ◽  
High Laser Fluence ◽  
Microscopy Techniques

AbstractThe effects of laser energy fluence on the growth of pulsed laser deposited ZnO thin films on c-plane sapphire substrates were systematically investigated by using x-ray diffraction, Rutherford backscattering spectrometry with ion channeling, and scanning electron microscopy techniques. Optical and electrical properties of the ZnO epilayers were characterized by using ultraviolet-visible transmission spectroscopy and Van der Pauw measurements, respectively. It was found that the laser fluence has strong effects on the crystalline, optical and electrical qualities of the ZnO films. At low laser fluence, ZnO film grows via 3D-island mode with low deposition rate, loss of Zn near the surface and particulates on top of the film. High laser fluence may also cause simultaneous multi-layer growth and the degradation of crystalline, electrical, and optical quality of the ZnO films. The optimal laser fluence window was found between 1.2J/cm2 and 2.5 J/cm2 for obtaining high quality ZnO films for optoelectronic applications. The dependence of laser fluence on the ZnO growth mode, surface morphology and electrical and optical properties is discussed.

Pulsed Laser Treatment of Virgin, Self and Europium Implanted Nickel: Evidence of Defect Impurity Interaction

1981 ◽  
Vol 7 ◽  
Author(s):  
G. Battaglin ◽  
A. Carnera ◽  
G. Della Mea ◽  
P. Mazzoldi ◽  
Animesh K. Jain ◽  
...  
Keyword(s):  
Solid Solution ◽  
Liquid Phase ◽  
Laser Treatment ◽  
Ruby Laser ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Metastable Solid Solution ◽  
Ion Channeling ◽  
Impurity Interaction ◽  
The Eu

ABSTRACTWe present a comparative study (by 1.8 MeV 4He+ ion channeling) of virgin, self and Eu implanted single crystals of nickel, under irradiation with single ruby laser pulses. The as implanted Eu is nearly non-substitutional and remains so, even after laser treatment. The comparative defect dechanneling behaviour provides explicit evidence of defect-impurity interaction which may be suppressing the formation of an expected metastable solid solution in the Eu-Ni system, which possesses miscibility in the liquid phase. A clear surface Eu peak appears at 2.1 J/cm2.

Transient Conductance Measurements During Pulsed Laser Annealing

1981 ◽  
Vol 4 ◽  
Author(s):  
M. O. Thompson ◽  
G. J. Galvin ◽  
J. W. Mayer ◽  
R. B. Hammond ◽  
N. Paulter ◽  
...  
Keyword(s):  
Single Crystal ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
Laser Pulses ◽  
Molten Layer ◽  
Pulsed Laser Annealing ◽  
Complete Melting ◽  
Solid Liquid Interface ◽  
Solid Liquid

ABSTRACTMeasurements were made of the conductance of single crystal Au-doped Si and silicon-on-sapphire (SOS) during irradiation with 30 nsec ruby laser pulses. After the decay of the photoconductive response, the sample conductance is determined primarily by the thickness and conductivity of the molten layer. For the single crystal Au-doped Si, the solid-liquid interface velocity during recrystallization was determined from the current transient to be 2.5 m/sec for energy densities between 1.9 and 2.6 J/cm2, in close agreement with numerical simulations based on a thermal model of heat flow. SOS samples showed a strongly reduced photoconductive response, allowing the melt front to be observed also. For complete melting of a 0.4 μm Si layer, the regrowth velocity was 2.4 m/sec.

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.

scholarly journals Synthesis and Properties of Platinum Nanoparticles by Pulsed Laser Ablation in Liquid

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Maria Isabel Mendivil Palma ◽  
Bindu Krishnan ◽  
Guadalupe Alan Castillo Rodriguez ◽  
Tushar Kanti Das Roy ◽  
David Avellaneda Avellaneda ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Photoelectron Spectroscopy ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Pt Nanoparticles ◽  
Pulsed Laser Ablation ◽  
Laser Ablation In Liquid ◽  
Visible Absorption ◽  
Energy Fluence ◽  
Ablation Time

Platinum (Pt) nanoparticles were synthesized by pulsed laser ablation in liquid (PLAL) technique in different liquids (acetone, ethanol, and methanol). Ablation was performed using a Q-switched Nd:YAG laser with output energy of 230 mJ/pulse for 532 nm wavelength. Ablation time and laser energy fluence were varied for all the liquids. Effects of laser energy fluence, ablation time, and nature of the liquid were reported. The mean size, size distributions, shape, elemental composition, and optical properties of Pt nanoparticles synthesized by PLAL were examined by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-Visible absorption spectroscopy.

Er3+-Doped Silicon Prepared by Laser Doping

1993 ◽  
Vol 301 ◽  
Author(s):  
T. Asatsuma ◽  
P. Dodd ◽  
J. F. Donegan ◽  
J. G. Lunney ◽  
J. Hegarty
Keyword(s):  
Rare Earth ◽  
Pulsed Laser ◽  
Earth Metal ◽  
Optically Active ◽  
Rare Earth Ions ◽  
Molten Layer ◽  
Laser Doping ◽  
Doped Silicon ◽  
Preliminary Study ◽  
The Rare Earth

ABSTRACTWe have carried out an investigation of the laser doping of Si with rare-earth ions. In this technique a silicon surface coated with a thin layer of the rare-earth metal is melted with a pulsed laser, the dopant is mixed in the molten layer, and incorporated in the crystal during regrowth. Er was chosen for the main part of our work as it is the best characterized of the rare-earth ions in Si. Luminescence is observed around 1.54µm and is assigned to optical transitions on Er3+ ions. This preliminary study shows that this new technique is viable for the production of optically active Er3+ in Si.

Low Temperature Laser-Doping Process Using PSG and BSG Films for Poly-Si TFTs

2000 ◽  
Vol 621 ◽  
Author(s):  
Cheon-Hong Kim ◽  
Sang-Hoon Jung ◽  
Jae-Hong Jeon ◽  
Min-Koo Han
Keyword(s):  
Energy Density ◽  
Low Temperature ◽  
Sheet Resistance ◽  
Laser Energy ◽  
Surface Concentration ◽  
Laser Pulses ◽  
Laser Energy Density ◽  
Silicon Thin Film ◽  
Laser Doping ◽  
Si Films

ABSTRACTA simple low-temperature excimer-laser doping process employing phosphosilicate glass (PSG) and borosilicate glass (BSG) films as dopant sources is proposed in order to form source and drain regions for polycrystalline silicon thin film transistors (poly-Si TFTs). We have successfully controlled sheet resistance and dopant depth profile of doped poly-Si films by varying PH3/SiH4 flow ratio, laser energy density and the number of laser pulses. The penetration depth and the surface concentration of dopants were increased with increasing laser energy density and the number of laser pulses. The minimum sheet resistance of 450ω/ for phosphorus (P) doping and 1100ω/ for boron (B) doping were successfully obtained. Our experimental results show that the proposed laser-doping process is suitable for source/drain formation of poly-Si TFTs.

Oxidation and Nitridation by Pulsed Laser Irradiation of Solids Immersed in Liquids

1986 ◽  
Vol 75 ◽  
Author(s):  
S. Roorda ◽  
A. Polman ◽  
S. B. Ogale ◽  
F. W. Saris
Keyword(s):  
Laser Irradiation ◽  
Rutherford Backscattering Spectrometry ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Processing Parameters ◽  
Initial Surface ◽  
X Ray Diffraction ◽  
Compound Formation ◽  
Pulsed Laser Irradiation

AbstractNitridation and oxidation of titanium is achieved by pulsed laser irradiation of Ti immersed in liquid ammonia or water. Rutherford Backscattering Spectrometry shows that large amounts of nitrogen and oxygen can be incorporated in the metal surface to a depth of several 1000 Å. X-ray diffraction shows evidence of compound formation. Scanning Electron Microscopy reveals that initial surface texture is smoothed, and that stress induced cracks and holes may appear. Irradiation of Fe and Si immersed in various liquids shows that modification depends on which combination of solid and liquid is used. Influence of processing parameters such as laser-energy density and number of laser pulses on compound formation has been investigated. The process is viewed as a reactive solute incorporation in the laser melted surface layer, followed by compound formation.

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