scholarly journals Creation and Evaluation of Atomically Ordered Side- and Facet-Surface Structures of Three-Dimensional Silicon Nano-Architectures

2020 ◽  
Author(s):  
Azusa N. Hattori ◽  
Ken Hattori
Keyword(s):  
Electron Diffraction ◽  
Surface Science ◽  
Three Dimensional ◽  
Annealing Treatment ◽  
High Energy ◽  
Energy Electron ◽  
Atomic Scale ◽  
Methods Of Evaluation ◽  
Facet Surface ◽  
Microscopy Techniques

The realization of three-dimensional (3D)-architected nanostructures, that is, the transformation from novel two-dimensional (2D) film-based devices to 3D complex nanodevices, is of crucial importance with the progress of scaling down devices to nanometer order. However, little attention has been devoted to controlling the atomic ordering and structures of side-surfaces on 3D structures, while techniques for controlling and investigating 2D surfaces, namely, surface science, have been established only for planar 2D surfaces. We have established an original methodology that enables atomic orderings and arrangements of surfaces with arbitrary directions to be observed on 3D figured structures by developing diffraction and microscopy techniques. An original technique, namely, directly and quantitatively viewing the side- and facet-surfaces at the atomic scale by reflection high-energy electron diffraction (RHEED) and low-energy electron diffraction (LEED), can be used to determine process parameters in etching. This chapter introduces methods of evaluation by RHEED and LEED based on a reciprocal space map and methods of creating various atomically flat 111 and {100} side-surfaces of 3D Si nano-architectures and tilted 111 facet-surfaces fabricated by lithography dry and wet etching processes, followed by annealing treatment in vacuum.

Modifications of a JEOL 2000EX TEM for insSitu surface studies

1993 ◽  
Vol 51 ◽  
pp. 640-641
Author(s):  
Michael T. Marshall ◽  
Xianghong Tong ◽  
J. Murray Gibson
Keyword(s):  
Electron Diffraction ◽  
Surface Science ◽  
Film Growth ◽  
High Vacuum ◽  
High Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Transmission Electron ◽  
Fundamental Insight

We have modified a JEOL 2000EX Transmission Electron Microscope (TEM) to allow in-situ ultra-high vacuum (UHV) surface science experiments as well as transmission electron diffraction and imaging. Our goal is to support research in the areas of in-situ film growth, oxidation, and etching on semiconducter surfaces and, hence, gain fundamental insight of the structural components involved with these processes. The large volume chamber needed for such experiments limits the resolution to about 30 Å, primarily due to electron optics. Figure 1 shows the standard JEOL 2000EX TEM. The UHV chamber in figure 2 replaces the specimen area of the TEM, as shown in figure 3. The chamber is outfitted with Low Energy Electron Diffraction (LEED), Auger Electron Spectroscopy (AES), Residual Gas Analyzer (RGA), gas dosing, and evaporation sources. Reflection Electron Microscopy (REM) is also possible. This instrument is referred to as SHEBA (Surface High-energy Electron Beam Apparatus).The UHV chamber measures 800 mm in diameter and 400 mm in height. JEOL provided adapter flanges for the column.

Kinematical Analysis of the Evolution of Reflection High Energy Electron Diffraction Patterns of Quantum Dot Heterostructures: Correlation with Strain and Anisotropy

2006 ◽  
Vol 924 ◽  
Author(s):  
Andrea Feltrin ◽  
Alexandre Freundlich
Keyword(s):  
Quantum Dots ◽  
Electron Diffraction ◽  
Quantum Dot ◽  
Three Dimensional ◽  
High Energy ◽  
Image Features ◽  
Energy Electron ◽  
Clear Correlation ◽  
High Energy Electron ◽  
Strain Anisotropy

ABSTRACTThe strain distributions and of reflection high energy electron diffraction (RHEED) patterns of uncapped pyramidal shape InAs Stranski-Krastanov quantum dots fabricated on GaAs(001) substrate are investigated theoretically. The three dimensional strain anisotropy is computed with an atomistic elasticity approach, using inter-atomic Keating potentials and the strain energy is minimized using the conjugate gradient numerical method. RHEED images are predicted in the framework of the kinematical theory, by taking into account the refraction of the electron beam at the quantum dot/vacuum interface. Clear correlation between RHEED image features and quantum dot structural properties is established. The study stresses the potential of RHEED for future experimental real-time (during growth) detections and deciphering of strain anisotropies in quantum dots.

INTERPRETATION OF REFLECTION HIGH ENERGY ELECTRON DIFFRACTION FROM DISORDERED SURFACES: DYNAMICAL THEORY AND ITS APPLICATION TO THE EXPERIMENT

1999 ◽  
Vol 06 (03n04) ◽  
pp. 461-495 ◽  
Author(s):  
UWE KORTE
Keyword(s):  
Electron Diffraction ◽  
Multiple Scattering ◽  
Surface Science ◽  
Phonon Scattering ◽  
High Energy ◽  
Dynamical Theory ◽  
Energy Electron ◽  
Advanced Materials ◽  
Quantitative Interpretation ◽  
High Energy Electron

Reflection high energy electron diffraction (RHEED) is one of the few surface science techniques that are applied in a fabrication process, namely to monitor the epitaxial growth of ultrathin films and advanced materials. In spite of this technological relevance the multiple scattering nature of the involved scattering processes has hindered the quantitative interpretation of RHEED in the case of real, i.e. imperfect, surfaces for a long time. This article reviews recent progress in the understanding of RHEED from surfaces exhibiting various types of disorder. It concentrates on a multiple scattering formalism — based on perturbation theory with the nonperiodic part of the structure as perturbation — that allows the computation and interpretation of RHEED from real systems. The validity regime of the approach is discussed. We demonstrate the potential of the method by its application to the quantitative interpretation of experimental data. The range of treated problems comprises occupational disorder, intensity oscillations, structure of disordered metal/adsorbate systems, diffuse scattering from adatoms, Kikuchi scattering and phonon scattering.

Kinematic Approximations in TED and RHEED Analysis of Reconstructed Surfaces

1990 ◽  
Vol 48 (2) ◽  
pp. 396-397
Author(s):  
L. -M. Peng ◽  
M. J. Whelan
Keyword(s):  
Electron Diffraction ◽  
Kinematic Analysis ◽  
Incident Beam ◽  
High Energy ◽  
Energy Electron ◽  
Great Success ◽  
High Energy Electron ◽  
Kinematic Approximation ◽  
Reconstructed Surfaces

In recent years there has been a trend in the structure determination of reconstructed surfaces to use high energy electron diffraction techniques, and to employ a kinematic approximation in analyzing the intensities of surface superlattice reflections. Experimentally this is motivated by the great success of the determination of the dimer adatom stacking fault (DAS) structure of the Si(111) 7 × 7 reconstructed surface.While in the case of transmission electron diffraction (TED) the validity of the kinematic approximation has been examined by using multislice calculations for Si and certain incident beam directions, far less has been done in the reflection high energy electron diffraction (RHEED) case. In this paper we aim to provide a thorough Bloch wave analysis of the various diffraction processes involved, and to set criteria on the validity for the kinematic analysis of the intensities of the surface superlattice reflections.The validity of the kinematic analysis, being common to both the TED and RHEED case, relies primarily on two underlying observations, namely (l)the surface superlattice scattering in the selvedge is kinematically dominating, and (2)the superlattice diffracted beams are uncoupled from the fundamental diffracted beams within the bulk.

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