scholarly journals Precise control of atoms with MBE: from semiconductors to complex oxides

2020 ◽  
Vol 51 (4) ◽  
pp. 21-23
Author(s):  
Y. Eren Suyolcu ◽  
Gennady Logvenov
Keyword(s):  
Molecular Beam ◽  
High Vacuum ◽  
Complex Oxides ◽  
Atomic Layer ◽  
Atomic Clusters ◽  
Ultra High Vacuum ◽  
Mbe Growth ◽  
Precise Control ◽  
Material Systems ◽  
Layer Control

Molecular Beam Epitaxy (MBE) is a high-vacuum technique with atomic-layer control and precision. It is based on the chemical reaction of the atoms, molecules, or atomic clusters vaporized from the specific evaporation sources on the substrates. The molecular beam defines a unidirectional ballistic flow of atoms and/or molecules without any collisions amongst. In the late 1960s, MBE was initially developed for the growth of GaAs and (Al, Ga)As systems[1,2] due to the unprecedented capabilities and then was applied to study other material systems. MBE growth is conventionally performed in vacuum and ultra-high vacuum (UHV) (10-8–10-12 mbar) conditions.

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

Coverage and Stability of NHx Terminated Cobalt and Ruthenium Surfaces: a First Principles Investigation

2019 ◽  
Author(s):  
Ji Liu ◽  
Michael Nolan
Keyword(s):  
Metal Surfaces ◽  
High Vacuum ◽  
Atomic Layer ◽  
Nitrogen Plasma ◽  
Operating Conditions ◽  
Ultra High Vacuum ◽  
Bridge Site ◽  
Stable Surface ◽  
Saturation Coverage ◽  
The Stability

<div>In the atomic layer deposition (ALD) of Cobalt (Co) and Ruthenium (Ru) metal using nitrogen plasma, the structure and composition of the post N-plasma NHx terminated (x = 1 or 2) metal surfaces are not well known but are important in the subsequent metal containing pulse. In this paper, we use the low-index (001) and (100) surfaces of Co and Ru as models of the metal polycrystalline thin films. The (001) surface with a hexagonal surface structure is the most stable surface and the (100) surface with a zigzag structure is the least stable surface but has high reactivity. We investigate the stability of NH and NH2 terminations on these surfaces to determine the saturation coverage of NHx on Co and Ru. NH is most stable in the hollow hcp site on (001) surface and the bridge site on the (100) surface, while NH2 prefers the bridge site on both (001) and (100) surfaces. The differential energy is calculated to find the saturation coverage of NH and NH2. We also present results on mixed NH/NH2-terminations. The results are analyzed by thermodynamics using Gibbs free energies (ΔG) to reveal temperature effects on the stability of NH and NH2 terminations. Ultra-high vacuum (UHV) and standard ALD</div><div>operating conditions are considered. Under typical ALD operating conditions we find that the most stable NHx terminated metal surfaces are 1 ML NH on Ru (001) surface (350K-550K), 5/9 ML NH on Co (001) surface (400K-650K) and a mixture of NH and NH2 on both Ru (100) and Co (100) surfaces.</div>

Molecular beam and solid-phase epitaxies of silicon under ultra-high vacuum

1978 ◽  
Vol 45 ◽  
pp. 287-291 ◽  
Author(s):  
Y. Shiraki ◽  
Y. Katayama ◽  
K.L.I. Kobayashi ◽  
K.F. Komatsubara
Keyword(s):  
Molecular Beam ◽  
Solid Phase ◽  
High Vacuum ◽  
Ultra High Vacuum

In-Situ Rapid Thermal Annealing of Heterostructures Grown by Molecular Beam Epitaxy

1987 ◽  
Vol 102 ◽  
Author(s):  
M. Cerullo ◽  
Julia M. Phillips ◽  
M. Anzlowar ◽  
L. Pfeiffer ◽  
J. L. Batstone ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Molecular Beam ◽  
High Vacuum ◽  
Processing Technique ◽  
Ultra High Vacuum ◽  
On Line ◽  
High Vacuum Environment

ABSTRACTA new in-situ rapid thermal annealing (RTA) apparatus which can be used to anneal entire wafers in an ultra high vacuum environment has been designed to be used in conjunction with the epitaxial growth of heterostructures. Drastic improvement in the crystallinity of CaF2/Si(100) can be achieved with RTA, and our results suggest that RTA can be used as an on-line processing technique for novel epitaxial structures.

Ultra-high-vacuum epitaxial growth of MgB2(0001) thin films on Mg(0001) via molecular beam epitaxy

2004 ◽  
Vol 16 (33) ◽  
pp. S3451-S3458 ◽  
Author(s):  
R Macovez ◽  
C Cepek ◽  
M Sancrotti ◽  
A Goldoni ◽  
L Petaccia ◽  
...  
Keyword(s):  
Thin Films ◽  
Molecular Beam Epitaxy ◽  
Epitaxial Growth ◽  
Molecular Beam ◽  
High Vacuum ◽  
Ultra High Vacuum

μm-Scale Lateral Growth of Ga-Monolayers Observed In-Situ by Electron Microscopy

1989 ◽  
Vol 159 ◽  
Author(s):  
J. Osaka ◽  
N. Inoue
Keyword(s):  
Electron Microscopy ◽  
Secondary Electron ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Intensity Difference ◽  
Lateral Growth ◽  
Mbe Growth ◽  
Electron Intensity ◽  
Scanning Electron

ABSTRACTAn ultra high vacuum scanning electron microscope equipped to an MBE system is utilized to study a transient of a surface atomic structure during MBE growth of GaAs and AlGaAs by the alternate supply method. Lateral growth of a Ga-monolayer over microns is realized utilizing Ga droplets. This is confirmed by discriminating the Ga and As top layer by using the secondary electron intensity difference between the Ga and As top layer. The growth mechanism of the Ga monolayer is discussed based on the results.

Design and Experimental Study of Deposition Temperature Control System in Ultra-High Vacuum

2012 ◽  
Vol 571 ◽  
pp. 564-568
Author(s):  
Zhi Dan Yan ◽  
Li Dong Sun ◽  
Chun Guang Hu ◽  
Xiao Tang Hu ◽  
Peter Zeppenfeld
Keyword(s):  
Control System ◽  
Temperature Control ◽  
Deposition Temperature ◽  
Film Growth ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Temperature Control System ◽  
Growth Morphology ◽  
Precise Control ◽  
Key Factor

Deposition temperature is a key factor influencing the growth morphology of thin-films, aiming at this phenomenon, a precise control system of deposition temperature in ultra-high vacuum is developed in the paper. It can realize accurate temperature control in a range of 150K to 450K during experiment by combination of resistance heating up and liquid helium cooling down strategies, which is benefit to further understand the temperature-depended mechanism of organic molecule thin-film growth. Besides, it is experimentally studied that the growth morphology of p-6p molecules on a mica substrate is closely related to the substrate deposition temperature, indicating that the length of p-6p nano-fibers is proportional to the deposition temperature, while their distribution density is inversely proportional to the temperature.

Amorphous Silicon Films and Superlattices Grown by Molecular Beam Epitaxy: An Optical Analysis

2002 ◽  
Vol 715 ◽  
Author(s):  
D. J. Lockwood ◽  
J.-M. Baribeau ◽  
M. Noël ◽  
J. C. Zwinkels ◽  
B. J. Fogal ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Amorphous Silicon ◽  
Molecular Beam ◽  
Crystalline Silicon ◽  
Quartz Substrate ◽  
High Vacuum ◽  
Impurity Content ◽  
Thin Layers ◽  
Silicon Films ◽  
Ultra High Vacuum

AbstractWe produce a novel form of amorphous silicon through ultra-high-vacuum molecular beam epitaxy. By depositing silicon atoms onto a fused quartz substrate at temperatures between 98 and 335°C, we obtain a silicon-based material that lacks the characteristic periodicity of crystalline silicon but nevertheless has 98% of its density. The impurity content of this material is studied through infrared and secondary ion mass spectroscopies. The primary impurity found is oxygen, with hydrogen and carbon atoms also being found at trace levels. The Raman spectra of the amorphous silicon films are measured and the results, as they relate to the presence of disorder, are interpreted. We also use this molecular beam epitaxy method to fabricate a number of amorphous silicon superlattices, comprised of thin layers of amorphous silicon separated with even thinner layers of SiO2. The optical properties of the films and superlattices are contrasted.

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