A Numerical Simulation of Pulsed Laser Deposition

1994 ◽  
Vol 354 ◽  
Author(s):  
William T. Laughlin ◽  
Edmond Y. Lo

AbstractA numerical simulation of the pulsed laser deposition process has been developed. This model is applied to pulsed laser deposition of carbon, a solid lubricant material. At laser fluences above the ablation threshold, the vapor density and temperature at the substrate are sufficiently high that a continuum flow exists. For typical pulsed laser deposition parameters, plume vapor temperatures and densities are insufficient for significant ionization. However, plume absorption does take place and is regulated by wavelength dependent absorption cross sections of the molecular species. Vapor expansion velocities depend on the absorption of laser radiation and thus the laser wavelength. A simple kinetic theory of deposition predicts the film deposition rate and film thickness profile.

1995 ◽  
Vol 395 ◽  
Author(s):  
Robert Leuchtner ◽  
W. Brock ◽  
Y. Li ◽  
L. Hristakos

ABSTRACTOriented GaN has been successfully grown at low substrate temperatures (∼480°C) on a- and r-planes of sapphire, using the pulsed laser deposition process. We have examined the effects of several deposition parameters on film growth, including substrate temperature (∼50–500°C), ambient pressure (1×10−3 – 10 torr of NH3), and target material (Ga or GaN). The film deposition rate was typically ∼3–4 μm/hr. Film characterization was performed using x-ray diffraction (XRD), optical microscopy, x-ray photoelectron spectrometry (XPS), and atomic force microscopy (AFM). In the case of the Ga metal target, a plasma (∼500V) between the target and substrate was necessary to promote formation of the GaN phase. The ammonia ambient enhanced the nitrogen content in the films compared to vacuum deposition. In general, the GaN target yielded better quality films (smaller rocking curve widths and smoother film morphology) compared to the Ga metal target. These results suggest that pulsed laser deposition is a promising approach to fabricating high quality films of this potentially important semiconducting material.


2010 ◽  
Vol 75 ◽  
pp. 202-207
Author(s):  
Victor Ríos ◽  
Elvia Díaz-Valdés ◽  
Jorge Ricardo Aguilar ◽  
T.G. Kryshtab ◽  
Ciro Falcony

Bi-Pb-Sr-Ca-Cu-O (BPSCCO) and Bi-Pb-Sb-Sr-Ca-Cu-O (BPSSCCO) thin films were grown on MgO single crystal substrates by pulsed laser deposition. The deposition was carried out at room temperature during 90 minutes. A Nd:YAG excimer laser ( = 355 nm) with a 2 J/pulse energy density operated at 30 Hz was used. The distance between the target and substrate was kept constant at 4,5 cm. Nominal composition of the targets was Bi1,6Pb0,4Sr2Ca2Cu3O and Bi1,6Pb0,4Sb0,1Sr2Ca2Cu3OSuperconducting targets were prepared following a state solid reaction. As-grown films were annealed at different conditions. As-grown and annealed films were characterized by XRD, FTIR, and SEM. The films were prepared applying an experimental design. The relationship among deposition parameters and their effect on the formation of superconducting Bi-system crystalline phases was studied.


1998 ◽  
Author(s):  
Dana Miu ◽  
Aurelian Marcu ◽  
T. Yukawa ◽  
Constantin Grigoriu ◽  
Ioan Chis ◽  
...  

MRS Bulletin ◽  
1992 ◽  
Vol 17 (2) ◽  
pp. 30-36 ◽  
Author(s):  
Jeff Cheung ◽  
Jim Horwitz

The laser, as a source of “pure” energy in the form of monochromatic and coherent photons, is enjoying ever increasing popularity in diverse and broad applications from drilling micron-sized holes on semiconductor devices to guidance systems used in drilling a mammoth tunnel under the English Channel. In many areas such as metallurgy, medical technology, and the electronics industry, it has become an irreplaceable tool.Like many other discoveries, the various applications of the laser were not initially defined but were consequences of natural evolution led by theoretical studies. Shortly after the demonstration of the first laser, the most intensely studied theoretical topics dealt with laser beam-solid interactions. Experiments were undertaken to verify different theoretical models for this process. Later, these experiments became the pillars of many applications. Figure 1 illustrates the history of laser development from its initial discovery to practical applications. In this tree of evolution, Pulsed Laser Deposition (PLD) is only a small branch. It remained relatively obscure for a long time. Only in the last few years has his branch started to blossom and bear fruits in thin film deposition.Conceptually and experimentally, PLD is extremely simple, probably the simplest among all thin film growth techniques. Figure 2 shows a schematic diagram of this technique. It uses pulsed laser radiation to vaporize materials and to deposit thin films in a vacuum chamber. However, the beam-solid interaction that leads to evaporation/ablation is a very complex physical phenomenon. The theoretical description of the mechanism is multidisciplinary and combines equilibrium and nonequilibrium processes. The impact of a laser beam on the surface of a solid material, electromagnetic energy is converted first into electronic excitation and then into thermal, chemical, and even mechanical energy to cause evaporation, ablation, excitation, and plasma formation.


2005 ◽  
Vol 44 (11) ◽  
pp. 7896-7900 ◽  
Author(s):  
Takahiro Nagata ◽  
Young-Zo Yoo ◽  
Parhat Ahmet ◽  
Toyohiro Chikyow

1999 ◽  
Vol 574 ◽  
Author(s):  
D. Kumar ◽  
K. G. Cho ◽  
Zhang Chen ◽  
V. Craciun ◽  
P. H. Holloway ◽  
...  

AbstractThe growth, structural and cathodoluminescent (CL) properties of europium activated yttrium oxide (Eu:Y2O3) thin films are reported. The Eu:Y2O3 films were grown in-situ using a pulsed laser deposition technique. Our results show that Eu:Y2O3 films can grow epitaxially on (100) LaAlO3 substrates under optimized deposition parameters. The epitaxial growth of Eu:Y2O3 films on LaAlO3, which has a lattice mismatch of ∼ 60 %, is explained by matching of the atom positions in the lattices of the film and the substrate after a rotation. CL data from these films are consistent with highly crystalline Eu:Y2O3 films with an intense CL emission at 611 nm.


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