GROWTH, MORPHOLOGICAL AND STRUCTURAL PROPERTIES OF Ag THIN FILMS ON A Ru (0001) SURFACE GROWN BY MBE

2004 ◽  
Vol 11 (06) ◽  
pp. 563-568
Author(s):  
A. AZIZI ◽  
J. ARABSKI ◽  
A. DINIA
Keyword(s):  
Thin Films ◽  
Lattice Mismatch ◽  
Three Dimensional ◽  
Xrd Analysis ◽  
High Energy ◽  
Growth Direction ◽  
Layer Growth ◽  
Layer By Layer ◽  
Force Microscopy ◽  
Xrd Techniques

Ag thin films deposited on Ru (0001) surface by molecular beam epitaxy, at temperatures of 20°C and 450°C, have been investigated using reflection high-energy electron diffraction (RHEED), atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. For both growth temperatures, the in situ RHEED patterns of the Ag films exhibited an in-plane six-fold symmetry, indicating that the Ag deposit is in epitaxy with the Ru buffer surface. At RT, the RHEED technique indicated a three-dimensional growth (3D), while a layer-by-layer growth (2D) takes place at HT. The AFM images showed a granular structure of the surface of the deposited Ag layers with a large variation of the roughness with the growth temperature. XRD analysis gave indication of a strongly textured thin film along the growth direction. The lattice mismatch between the Ag and Ru is at the origin of a stress at the interface and defects structure in the film.

Atomic Layer and Unit-Cell Layer Growth of (Ca,Sr)CuO2 and Bi2Sr2Can-1CunO2n+4 Thin Films by Laser Molecular Bean Epitaxy

1991 ◽  
Vol 222 ◽  
Author(s):  
Masaki Kanai ◽  
Tomoji Kawai ◽  
Takuya Matsumoto ◽  
Shichio Kawai
Keyword(s):  
Thin Films ◽  
Diffraction Pattern ◽  
Cell Layer ◽  
Atomic Layer ◽  
High Energy ◽  
Layer Growth ◽  
Unit Cell ◽  
Layer By Layer ◽  
Diffraction Intensity

ABSTRACTThin films of (Ca,Sr)CuO2 and Bi2Sr2Can-1CunO2n+4 are formed by laser molecular beam epitaxy with in-situ reflection high energy electron diffraction observation. The diffraction pattern shows that these materials are formed with layer-by-layer growth. The change of the diffraction intensity as well as the analysis of the total diffraction pattern makes It possible to control the grown of the atomic layer or the unit-cell layer.

Rheed Intensity Oscillation During Layer-by-Layer Growth of Bi-Sr-Ca-Cu-O Thin Films

1992 ◽  
Vol 275 ◽  
Author(s):  
K. Yoshikawa ◽  
N. Sasaki
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
High Energy ◽  
Layer Growth ◽  
Layer By Layer ◽  
Two Dimensional ◽  
Growth Interruption ◽  
Layer Deposition ◽  
Unit Cells ◽  
Layered Growth

ABSTRACTUsing in-situ reflection high-energy electron diffraction (RHEED), we studied the growth of Bi-Sr-Ca-Cu-O (BSCCO) thin films prepared by reactive evaporation using layer-by-layer deposition. Bi2Sr2CaCu2Ox(2212) tends to be grown three-dimensionally if it is grown directly on (100) SrTiO3, in contrast to Bi2Sr2CuOx(2201) which is easily grown two-dimensionally on SrTiO3. Two-dimensional 2212 growth can be realized, if a buffer layer of 2201 is deposited on (100) SrTiO3 and growth interruption is utilized after SrO layer deposition. A buffer layer of only two 2201 unit cells improved the surface crystallinity of the substrate for the epitaxial growth of 2212. Growth interruption for two minutes after the 2nd SrO layer in the half unit cell is necessary to keep two-dimensional layered growth. The resulting Tc (zero) is 76 K and Jc (at 4.2 K) is 1.5 × 106 (A/cm2) with these epitaxial films.

Effects of Stress on Step Energies and Surface Roughness

MRS Bulletin ◽  
1996 ◽  
Vol 21 (4) ◽  
pp. 27-30 ◽  
Author(s):  
Christopher Roland
Keyword(s):  
Thin Films ◽  
Strain Relaxation ◽  
Three Dimensional ◽  
Layer Growth ◽  
Growth Mode ◽  
Misfit Dislocations ◽  
Layer By Layer ◽  
Strained Layers ◽  
The Subject ◽  
Growth Changes

Strain relaxation in lattice-mismatched, heteroepitaxial systems is one of the classic problems in materials physics, which has gained new urgency with the increased applications of strained layers in microelectronic systems. In general both the structure and the integrity of the thin films are strongly influenced by strain. For instance it has long been known that under strain, the growth changes from an initial layer-by-layer growth mode to one with three-dimensional islanding. In the seminal works of van der Merwe, and Matthews and Blakeslee, this change in growth mode is explained in terms of the introduction of strain-relieving misfit dislocations, which appear when the film has reached some critical thickness. Recently it has become clear that this change in growth mode can take place even without the introduction of misfit dislocations. Such dislocation-free coherent islanding, or “roughening,” has been observed experimentally both in Ge/Si and in InGaAs/GaAs systems. Furthermore recent experiments show that in Ge/Si(100) systems, the thin films display a curious asymmetry with respect to the sign of the strain: Films under compression roughen by forming coherent islands while those under tension remain relatively smooth. A possible mechanism behind this strain-induced type of roughening is the subject of this article.

Oxygen Pressure Dependence of Morphology of Morphology of La2-xSrxCuO4 Ultra-Thin Films

1997 ◽  
Vol 11 (21n22) ◽  
pp. 981-987
Author(s):  
H. Q. Yin ◽  
T. Arakawa ◽  
Y. Kaneda ◽  
T. Yoshikawa ◽  
N. Haneji ◽  
...  
Keyword(s):  
Thin Films ◽  
Pressure Dependence ◽  
Film Growth ◽  
Ambient Pressure ◽  
High Energy ◽  
Layer Growth ◽  
Growth Mode ◽  
Layer By Layer ◽  
Island Growth ◽  
Experimental Conditions

La 2-x Sr x CuO 4 ultra-thin films with thickness 200 Å were fabricated by pulsed laser deposition method in oxygen ( O 2) atmosphere. The morphology of deposited films was investigated by reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM) and scanning electronic microscopy (SEM). The strong oxygen ambient pressure dependence of film morphology was observed. In high oxygen ambient pressure, the film growth is dominated by island growth mode. The results imply that the experimental conditions of oxygen ambient pressure and substrate temperature are critical for the layer-by-layer growth mode.

Preparation of (111)-Oriented Pt Electrode Films with Quasi-Monocrystal Properties on MgO/TiN Buffered Si(100) by PLD

2007 ◽  
Vol 280-283 ◽  
pp. 823-826 ◽  
Author(s):  
Tong Lai Chen ◽  
Xiao Min Li
Keyword(s):  
High Energy ◽  
Layer Growth ◽  
Atomic Scale ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Pt Electrode ◽  
Force Microscopy ◽  
Atomic Force

Atomic-scale smooth Pt electrode films have been deposited on MgO/TiN buffered Si (100) by the pulsed laser deposition (PLD) technique. The whole growth process of the multilayer films was monitored by using in-situ reflection high energy electron diffraction (RHEED) apparatus. The Pt/MgO/TiN/Si(100) stacked structure was also characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The HREED observations show that the growth mode of the Pt electrode film is 2D layer-by-layer growth. It is found that the (111)-oriented Pt electrode film has a crystallinity comparable to that of monocrystals. The achievement of the quasi-single-crystal Pt electrode film with an atomic-scale smooth surface is ascribed to the improved crystalline quality of the MgO film.

Temperature Effect on the Quality of Ain Thin Films

1998 ◽  
Vol 537 ◽  
Author(s):  
Margarita P. Thompson ◽  
Andrew R. Drews ◽  
Changhe Huang ◽  
Gregory W. Auner
Keyword(s):  
Thin Films ◽  
Growth Mechanism ◽  
Three Dimensional ◽  
Plasma Source ◽  
High Energy ◽  
Mis Structure ◽  
X Ray Diffraction ◽  
Diffuse Intensity ◽  
Force Microscopy ◽  
Atomic Force

AbstractAIN thin films were deposited at various substrate temperatures via Plasma Source Molecular Beam Epitaxy. The films were grown on 6H-SiC (0001) substrates. Reflection High Energy Electron Diffraction and Atomic Force Microscopy showed a dramatic change in the surface morphology of the film grown at 640°C. This is attributed to a change in the growth mechanism from pseudomorphic at lower temperatures to three-dimensional at higher than 640°C temperatures. Photoreflectance measurements showed an absorption shift toward 200 nm as the deposition temperature increases which is attributed to the change in the growth mechanism at higher temperatures. X-Ray Diffraction was unable to conclusively determine the AIN (0002) peak due to a significant diffuse intensity from the SiC (0002) peak. A MIS structure was created by depositing Pt contacts on the film grown at 500°C. I-V measurements showed that the Pt/AIN contact is Schottky.

Structure and Magnetic Properties of Epitaxial Ordered FePd (001) Thin Films

1996 ◽  
Vol 441 ◽  
Author(s):  
V. Gehanno ◽  
A. Marty ◽  
B. Gilles
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Microscopy Study ◽  
Growth Direction ◽  
Electron Microscopy Study ◽  
Layer Growth ◽  
Layer By Layer ◽  
Easy Magnetization ◽  
Transmission Electron ◽  
Magnetization Axis

AbstractEquiatomic FePd (001) thin films have been deposited by Molecular Beam Epitaxy on a Pd (001) surface. We show that the degree of chemical order in the epitaxial layer is highly dependant on the temperature of deposition thus leading to a drastic change in the magnetic properties. At 25°C, while the RHEED oscillations reveal a layer by layer growth, the structural study demonstrates that the disordered phase has grown. In that case, the easy magnetization axis lies in the plane of the layer. At 350°C, the RHEED oscillations show that the growth proceeds bilayer by bilayer. We find that the tetragonal L10 ordered phase is stabilized with its 4-fold symmetry axis along the growth direction and this results in a perpendicularly magnetized thin film. The Transmission Electron Microscopy study reveals the presence of twins and antiphase boundaries in the ordered film.

scholarly journals Temperature Effect on the Quality of A1N thin Films

1999 ◽  
Vol 4 (S1) ◽  
pp. 142-148
Author(s):  
Margarita P. Thompson ◽  
Andrew R. Drews ◽  
Changhe Huang ◽  
Gregory W. Auner
Keyword(s):  
Thin Films ◽  
Growth Mechanism ◽  
Three Dimensional ◽  
Plasma Source ◽  
High Energy ◽  
Mis Structure ◽  
X Ray Diffraction ◽  
Diffuse Intensity ◽  
Force Microscopy ◽  
Atomic Force

AlN thin films were deposited at various substrate temperatures via Plasma Source Molecular Beam Epitaxy. The films were grown on 6H-SiC (0001) substrates. Reflection High Energy Electron Diffraction and Atomic Force Microscopy showed a dramatic change in the surface morphology of the film grown at 640°C. This is attributed to a change in the growth mechanism from pseudomorphic at lower temperatures to three-dimensional at higher than 640°C temperatures. Photoreflectance measurements showed an absorption shift toward 200 nm as the deposition temperature increases which is attributed to the change in the growth mechanism at higher temperatures. X-Ray Diffraction was unable to conclusively determine the AlN (0002) peak due to a significant diffuse intensity from the SiC (0002) peak. A MIS structure was created by depositing Pt contacts on the film grown at 500°C. I-V measurements showed that the Pt/AlN contact is Schottky.

Pb Induced Layer-by-Layer Growth and the Dependence on an Amount of Surfactant in the Growth of Ni on Ni(100) Surface

1996 ◽  
Vol 441 ◽  
Author(s):  
M. Iwanami ◽  
M. Kamiko ◽  
T. Matsumoto ◽  
R. Yamamoto
Keyword(s):  
Film Growth ◽  
Three Dimensional ◽  
High Energy ◽  
Layer Growth ◽  
Embedded Atom Method ◽  
Layer By Layer ◽  
Homoepitaxial Growth ◽  
Embedded Atom ◽  
Series Of Experiments ◽  
Modified Embedded Atom Method

AbstractSurfactant epitaxy has been expected to be a powerful method to improve thin film growth from three dimensional island mode to layer-by-layer growth one. Supposing that Pb is the surfactant and Ni is the substrate and deposition metal, we have investigated how the surfactant atoms segregate on surface by computer simulations using the modified embedded atom method. To verify the effect of Pb on the homoepitaxial growth of Ni, we have performed a series of experiments on the growth of Ni on Ni(100) surface with and without Pb using reflection high energy electron diffraction (RHEED). It was clearly found that Pb induced layer-by-layer growth of Ni metal film. The result of the dependence of the growth behavior on the thickness of Pb layer suggests that there is the most suitable thickness of a surfactant layer which is not always the monolayer.

Afm Study of CeO2 Growth on Sapphire as a Buffer Layer for YBa2Cu3O7

1995 ◽  
Vol 401 ◽  
Author(s):  
M. W. Denhoff ◽  
B. F. Mason ◽  
H. T. Tran ◽  
P. D. Grant
Keyword(s):  
Ybco Film ◽  
Three Dimensional ◽  
Layer Growth ◽  
Granular Structure ◽  
Atomic Scale ◽  
Laser Deposition ◽  
Layer By Layer ◽  
Temperature Dependent ◽  
Force Microscopy ◽  
Atomic Force

AbstractThe structure of CeO2 films grown on (1102) sapphire and on YBCO thin films was investigated. The films reported on here were grown by pulsed excimer laser deposition and their surface structure was probed using atomic force microscopy. We found that CeO2 films grown on sapphire were epitaxial with a granular structure which is smooth on an atomic scale. We see evidence of a surface reconstruction on a very smooth CeO2 (100) oriented surface. At higher growth temperatures, three dimensional islands begin to form. When a CeO2 film is grown on top of a YBCO film, the growth mode is two dimensional. The steps in this layer by layer growth are a surprisingly large 2 nm. This is about equal to 4 times the CeO2 lattice constant. This step height appears to be temperature dependent.

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