Evolution of surface morphology during epitaxial growth

1993 ◽  
Vol 344 (1673) ◽  
pp. 493-505 ◽  
Keyword(s):  
Epitaxial Growth ◽  
Large Scale ◽  
High Energy ◽  
Atomic Scale ◽  
High Energy Electron ◽  
Vicinal Surfaces ◽  
Basic Model ◽  
Surface Steps ◽  
Simulated Surface ◽  
Surface Morphologies

We examine the type of information that can be obtained from Monte Carlo simulations of epitaxial growth. A basic model will be first introduced and some of the features that make it suitable for describing both atomic-scale processes and large-scale morphologies will be pointed out. The ability of this model to reproduce experimental data will then be addressed. The first example discussed will be growth on GaAs(OO1) vicinal surfaces, where the density of surface steps on the simulated surfaces reproduces quantitatively the evolution of the reflection high-energy electron diffraction (RHEED) intensity oscillations for appropriately chosen growth and diffraction conditions. This work will then be used as a basis for examining the predictions of the simulated surface morphologies on patterned substrates, based on comparisons with micro-RHEED measurements. Extensions of the basic model to more complex growth scenarios where the atomic constituents are delivered in the form of heteroatomic molecules will also be discussed.

From Adatom Migration to Chemical Kinetics: Models for MBE, Mombe and MOCVD

1993 ◽  
Vol 312 ◽  
Author(s):  
D. D. Vvedensky ◽  
T. Shitarat ◽  
P. Smilauer ◽  
T. Kaneko ◽  
A. Zangwill
Keyword(s):  
Experimental Data ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
High Energy ◽  
Atomic Scale ◽  
Basic Model ◽  
Mobile Species ◽  
Local Environments ◽  
Starting Point

AbstractThe application of Monte Carlo simulations to various epitaxial growth methods is examined from the standpoint of incorporating only those kinetics processes that are required to explain experimental data. A basic model for molecular-beam epitaxy (MBE) is first introduced and some of the features that make it suitable for describing atomic-scale processes are pointed out. Extensions of this model for cases where the atomic constituents of the growing surface are delivered in the form of heteroatomic molecules are then considered. The experimental scenarios that is discussed is the homoepitaxy of GaAs(001) using metalorganic molecular-beam epitaxy (MOMBE) with triethylgallium (TEG) and precursors and using MOCVD with trimethylgallium (TMG). For MOMBE, the comparisons between simulations and experiments are based on reflection high-energy electron diffraction intensities, by analogy with comparisons made for MBE, while for metalorganic chemical vapor deposition (MOCVD) the simulations are compared to in situ glancingincidence x-ray scattering measurements. In both of these cases, the inclusion of a second mobile species to represent the precursor together with various rules for the decomposition of this molecule (in terms of rates and local environments) with be shown to provide a useful starting point for explaining the general trends in the experimental data and for further refinements of the model.

The Influence of Diamond Surface Perfection on the Preferential Nucleation of SP2 Carbon During Methane Pyrolysis

1992 ◽  
Vol 280 ◽  
Author(s):  
B. Y. Lin ◽  
C. P. Beetz ◽  
D. W. Brown ◽  
B. A. Lincoln
Keyword(s):  
Natural Diamond ◽  
High Energy ◽  
Diamond Surface ◽  
Structural Defects ◽  
High Energy Electron ◽  
Diamond Surfaces ◽  
Preferential Nucleation ◽  
Cvd Diamond Film ◽  
Surface Morphologies ◽  
Methane Pyrolysis

ABSTRACTWe report a set of CH4 pyrolysis experiments in a UHV system on diamond surfaces having varying degrees of surface roughness or perfection. Scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and reflection high energy electron diffraction (RHEED) were used to examine the formation of graphite and the resulting surface morphologies. A (100) type Ha natural diamond having 3 sputtered craters on the surface was used as the substrate, sp2 carbon was formed preferentially on the structurally defective crater surfaces after ∼3×1010 L of CH4 exposure at 900°C, whereas essentially no sp2 carbon was found on the flat portions of the diamond surface. Similar experiments were also carried out on a polycrystalline CVD diamond film and sp2 carbon was formed on that surface afte ∼4×109 L of CH4 exposure at 900°C. These results indicate that structural defects on diamond surfaces are a crucial factor in the preferential nucleation of sp2 carbon during CH4 pyrolysis.

Step-Edge Barriers on GaAs(001)

1995 ◽  
Vol 399 ◽  
Author(s):  
P. Šmilauer ◽  
D.D. Vvedensky
Keyword(s):  
Kinetic Monte Carlo ◽  
Step Edge ◽  
Layer By Layer ◽  
Vicinal Surfaces ◽  
Activation Barriers ◽  
Long Time ◽  
Kinetic Monte Carlo Simulations ◽  
Simulated Surface ◽  
Constant Slope ◽  
Surface Morphologies

ABSTRACTWe investigate growth of GaAs(001) using kinetic Monte Carlo simulations of a very simple atomistic solid-on-solid model. The key features of this model are a short-range incorporation process of freshly deposited atoms and additional activation barriers to interlayer transport. Both are required to obtain close agreement between measured electron-diffraction intensities and simulated surface step densities during growth and post-growth equilibration on vicinal surfaces. This model is used to study long-time evolution of the surface morphology. Large pyramid-like features develop during growth on a singular surface which coarsen in time while maintaining an approximately constant slope. Growth on a vicinal surface is also found to be unstable. Simulated surface morphologies are compared with recent work using atomic-force microscopy. Finally, we show how a suitably modified version of this model helps to explain the recently observed phenomenon of re-entrant layer-by-layer chemical-beam etching of a singular GaAs(001) surface. The central features responsible for this behavior are the site selectivity of the etching process combined with step-edge barriers to interlayer adatom migration.

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