Surface and Microstructural Characterization of Homoepitaxial Silicon Grown by Pulsed Laser Deposition

2000 ◽  
Vol 616 ◽  
Author(s):  
J.S. Pelt ◽  
R. Magahñ;a ◽  
M.E. Ramsey ◽  
E. Poindexter ◽  
S. Atwell ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Microstructural Characterization ◽  
Thin Film Deposition ◽  
High Energy ◽  
Film Deposition ◽  
Laser Deposition ◽  
Reliable Technique ◽  
Transmission Electron ◽  
Substrate Temperatures

AbstractThere is a great deal of interest in thin film deposition techniques which can achieve good crystal quality at low substrate temperatures. Pulsed laser deposition (PLD), well-known as a reliable technique for fabrication of high critical temperature superconductor thin films, has a number of characteristics which may make it suitable for such applications. In particular, PLD is characterized by a relatively large average species energy, which can be controlled by the laser fluence at the target. This paper describes the growth of silicon on silicon films using PLD over substrate temperatures between 500 and 700 °C, and in-situ characterization using reflection high-energy electron diffraction (RHEED). Transmission electron microscopy confirms the growth of single crystal oriented films, and atomic force microscopy indicates smooth films with an rms surface roughness of less than 2 Å

Pulsed Laser Deposition History and Laser-Target Interactions

MRS Bulletin ◽  
1992 ◽  
Vol 17 (2) ◽  
pp. 30-36 ◽  
Author(s):  
Jeff Cheung ◽  
Jim Horwitz
Keyword(s):  
Thin Film ◽  
Laser Beam ◽  
Pulsed Laser Deposition ◽  
Mechanical Energy ◽  
Pulsed Laser ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Laser Deposition ◽  
Small Branch ◽  
The Impact

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.

Germanium Nanostructures Fabricated by PLD

1998 ◽  
Vol 536 ◽  
Author(s):  
K. M. Hassan ◽  
A. K. Sharma ◽  
J. Narayan ◽  
J. F. Muth ◽  
C. W. Teng
Keyword(s):  
Pulsed Laser Deposition ◽  
Electronic Transport ◽  
Pulsed Laser ◽  
Single Layer ◽  
Laser Deposition ◽  
Transmission Electron ◽  
The Matrix ◽  
Average Size ◽  
Substrate Temperatures

AbstractQuantum confined nanostructures of semiconductors such as Ge and Si are being actively studied due to their interesting optical and electronic transport properties. We fabricated Ge nanostructures buried in the matrix of polycrystalline-AIN grown on Si(111) by pulsed laser deposition at lower substrate temperatures than that used in previous studies. The characterization of these structures was performed using high resolution transmission electron microscopy (HRTEM), photoluminescence and Raman spectroscopy. HRTEM observations show that the Ge islands are single crystal with a pyramidal shape. The average size of Ge islands was determined to be 15 nm, considerably smaller than that produced by other techniques. The Raman spectrum reveals a peak downward shift, upto 295 cm−1, of the Ge-Ge mode caused by quantum confinement in the Ge-dots. Photoluminescence (PL) was observed both with a single layer of Ge nanodots embedded in the AlN matrix and from ten layers of dots interspersed with AIN. The PL of the dots was blue shifted by ˜0.266 eV from the bulk Ge value of 0.73 eV at 77 K, resulting in a distinct peak at ˜1.0 eV. The full width at half maximum (FWHM) of the peak was 13 meV, for the single layer and 8 meV for the ten layered sample, indicating that the Ge nanodots are fairly uniform in size, which was found to be consistent with our HRTEM results. The importance of pulsed laser deposition (PLD) in fabricating novel nanostructures is discussed.

Pulsed Laser Deposition of Laterally Graded X-Ray Optical Multilayers on Substrates of Technical Relevance

1995 ◽  
Vol 382 ◽  
Author(s):  
R. Dietsch ◽  
TH. Holz ◽  
R. Krawietz ◽  
H. Mai ◽  
B. SchÖneich ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Thickness Distribution ◽  
Pulsed Laser ◽  
Single Layer ◽  
Thin Film Deposition ◽  
Optical Quality ◽  
Film Deposition ◽  
Laser Deposition ◽  
Emission Characteristic ◽  
X Ray

ABSTRACTPulsed Laser Deposition (PLD) is used for the preparation of Ni/C, W/C, and Mo/Si multilayers having X-ray optical quality. For the synthesis of layer stacks involving a uniform or a graded thickness distribution across 4"-wafers the conventional thin film deposition equipment of PLD has been modified. This modification provides a precise spatial control of the plasma plume orientation in the deposition chamber. With this arrangement the emission characteristic of the plasma source can be computer controlled and the desired coating profile can be tailored across an extended substrate via a stepper-motor-driven target manipulator.Thus film thickness uniformity (δts < 2%) is obtained on substrates up to 4" diameter even for smaller target-substrate distances. For laterally graded Ni and C individual layers linear thickness gradients of dts/dx = 3.2 × 10−8 were confirmed over the total substrate length by spectroscopic ellipsometry. The parameters deduced from single layer deposition were applied for the synthesis of laterally graded Ni/C multilayers. A mean value of the gradient of the stack period thickness dt/dx = 6.2 × 10−8 confirmed by X-ray reflectometry (nominal value: dt0 /dx = 6.4×10−8 ) characterizes precision and reproducibility of the coating process.

Surface Dynamics of GaAs Thin Film Formation by Pulsed Laser Deposition Investigated Using RHEED

2002 ◽  
Vol 749 ◽  
Author(s):  
A. Pun ◽  
S.M. Durbin ◽  
J. Kennedy ◽  
A. Markwitz ◽  
R. Reeves ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Elevated Temperatures ◽  
Film Formation ◽  
Pulsed Laser ◽  
High Energy ◽  
Laser Deposition ◽  
Growth Surface ◽  
Surface Dynamics ◽  
Growth Mechanisms ◽  
Substrate Temperatures

ABSTRACTPost-growth surface dynamics of epitaxial GaAs (100) thin films grown by pulsed laser deposition (PLD) have been studied using dynamic reflection high-energy electron diffraction (RHEED) in an effort to better understand the growth mechanisms present in pulsed laser deposition. Results have indicated, as expected, that processes occurring at reduced substrate temperatures manifest themselves more slowly than at elevated temperatures. This has been shown through the analysis of static RHEED images and dynamic specular beam intensity as well as profile scans.

The Morphology of Polytetrafluoroethylene (PTFE) Thin Films Formed by Pulsed-Laser Deposition

1995 ◽  
Vol 385 ◽  
Author(s):  
M. Grant Norton ◽  
Wenbiao Jiang ◽  
J. Thomas Dickinson
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Interface Plane ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Film Substrate ◽  
Substrate Temperatures

ABSTRACTThin films of polytetrafluoroethylene have been formed by the pulsed-laser deposition technique. The structure of the films was found to be dependent upon the substrate temperature during deposition. At substrate temperatures from room temperature to 200°C the films were determined, by transmission electron microscopy and X-ray diffraction techniques, to be amorphous. Films formed at higher substrate temperatures were found to contain both amorphous and crystalline components. The data for the crystalline component is consistent with it being highly ordered with the long helical molecular chains aligned parallel to the film-substrate interface plane. The maximum amount of crystalline material occurred when the substrate temperature was close to the melting temperature of the polymer.

Fabrication of Micro Single Chamber Solid Oxide Fuel Cell Using Photolithography and Pulsed Laser Deposition

2015 ◽  
Vol 12 (2) ◽  
Author(s):  
Man Yang ◽  
Zhigang Xu ◽  
Salil Desai ◽  
Dhananjay Kumar ◽  
Jag Sankar
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Solid Oxide ◽  
Laser Deposition ◽  
Oxide Fuel ◽  
Single Chamber

This paper focuses on the fabrication of micro-coplanar interdigitated single chamber solid oxide fuel cell (μ-SC-SOFC) using a combination of micropatterning technique and thin-film deposition technology. Photolithography was used to generate the micro-interdigitated photoresist patterns on the substrates. Pulsed laser deposition (PLD) method was used to deposit thin films of microstructured electrolytes yttrium stabilized zirconia (YSZ) and electrodes (anode: YSZ + NiO and cathode: lanthanum strontium ferrous cobalt (LSCF)). Process parameters were optimized to obtain consistent functional microstructure and crystal morphology. This research shows good potential for combinatorial manufacturing methods to fabricate high quality and repeatable micro fuel cell components.

Mullite Diffusion Barriers for SiC-C/C Composites Produced by Pulsed Laser Deposition

1998 ◽  
Vol 555 ◽  
Author(s):  
H. Fritze ◽  
A. Schnittker ◽  
T. Witke ◽  
C. Rüscher ◽  
S. Weber ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Target Material ◽  
High Energy ◽  
Single Step ◽  
Laser Deposition ◽  
Reduced Pressure ◽  
Oxidation Rates ◽  
Energy Impact ◽  
Diffusion Parameters

AbstractPulsed Laser Deposition (PLD) allows the ablation of nonconductive and high melting point target materials and the preparation of films with complex composition. High energy impact leads to melting and evaporation of the target material in a single step. In case of mullite ablation, the flux of the metal components is stoichiometric. Under reduced pressure the oxygen content in the layers decreases. However, after a short oxidation treatment, the formation of mullite in the coating is completed, as confirmed by IR spectroscopy and XRD investigations. For a commercial Si-SiC precoated C/C material, the effectiveness of additional PLD mullite layers as outer oxidation protection is tested in the temperature range 773 K < T < 1873 K. Mullite coatings with a thickness of 2.5 pm improve the oxidation behaviour significantly. Because of SiO2 formation at the mullite-SiC interface, all samples exhibited a mass increase upon oxidation. For oxidation durations of three days, only amorphous SiO2 is formed at the mullite-SiC interface. The inward diffusion of oxygen across the outer mullite-containing layer controls the kinetics of the reaction, as was deduced from 18O diffusivity measurements in PLD mullite layers. At temperatures close to the eutectic temperature (1860 K), mullite can seal defects. The calculated oxidation rates resulting from the diffusion parameters in SiO2 and mullite are close to the thermogravimetric data.

Sign in / Sign up

Export Citation Format

Share Document