Dear Joao Fonseca,
Take a look at info presented below:
Using Kikuchi pattern obtained by RHEED the inner potential of (3×3)-Si reconstructed 6H-SiC was determined to be 15.4 V. Applying a semi-kinematical RHEED pattern simulation it was shown that in the case of two-dimensional diffraction it is possible to determine the polarity and the polytype structure of silicon carbide.
https://www.researchgate.net/publication/250340210_RHEED_A_tool_for_structural_investigations_of_thin_polytypic_SiC_layers
_____
_____
Silicon carbide is a material with a multi-stable crystallographic structure, i.e., a polytypic material. Different polytypes exhibit different band gaps and electronic properties with nearly identical basal plane lattice constants, making them interesting for heterostructures without concentration gradients. The controlled formation of this heterostructure is still a challenge. The ability to adjust a defined temperature–time profile using rapid thermal processing was used to imprint the polytype transitions by controlling the nucleation and structural evolution during the temperature ramp-up and the steady state. The influence of the linear heating-up rate velocity during ramp-up and steady-state temperature on the crystal structure of amorphized ion-implanted silicon carbide layers was studied and used to form hetero-polytype structures. Integrating the structural selection properties of the non-isothermal annealing stage of the ion-implanted layers into an epitaxial growth process allows the imprinting of polytype patterns in epitaxial layers due to the structural replication of the polytype pattern during epitaxial growth. The developed methodology paves the way for structural selection and vertical and lateral polytype patterning. In rapid thermal chemical vapor deposition, the adjustment of the process parameters or the buffer layer allowed the nucleation and growth of wurtzite silicon carbide.
https://www.mdpi.com/2073-4352/10/6/523
_____
_____
Len Leonid Mizrah thanks for your answer.
For a "common pattern" like the ones presented here : Article Structural properties and parameters of epitaxial silicon ca...
What type of information can we extract from streaks and dots presented in RHEED pattern, if you could provide me a good resource to learn on how to interpret this patterns I would be very grateful.
Best regards,
Joao Fonseca
Dear Joao Fonseca ,
Take a look at the clarifying sources below:
In this paper we present an overview of the diffraction technique known as reflection high energy electron diffraction (RHEED). We discuss an elementary approach behind the analysis of experimentally obtained RHEED patterns (including patterns we produced at the Stewart-Blusson Quantum Matter Institute). Meaningful information, such as atomic structure and surface topology, can be extracted from this technique. Furthermore, an explanation of the kinematic scattering theory is reviewed and an introduction to the effect of dynamic scattering through the observation of Kikuchi lines is given.
https://phas.ubc.ca/~berciu/TEACHING/PHYS502/PROJECTS/RHEED.pdf
_____
_____
What information can be obtained by RHEED applied on polycrystalline films?
In this paper, an analysis of reflection high-energy electron diffraction (RHEED) performed on polycrystalline films is presented. It is shown that it is possible to obtain qualitative and quantitative information about the crystallography of the deposit. Two series of test samples were used: (i) glass substrates recovered by Fe grains with a (200) fiber-like texture normal or inclined with respect to the surface normal, and (ii) the same films but with a (110) texture. These samples exhibit characteristic RHEED patterns. Using a simple model, it is possible to determine: (i) the texture of the film, (ii) the average angle of the texture axis with respect to the surface normal, and (iii) the angular width of the distribution of this angle about its average value.
https://www.researchgate.net/publication/239696073_What_information_can_be_obtained_by_RHEED_applied_on_polycrystalline_films
_____
_____
The epitaxial growth of complex oxide thin films provides three avenues to generate unique properties: the ability to influence the 3-dimensional structure of the film, the presence of a surface, and the generation of an interface. In all three cases, a clear understanding of the resulting atomic structure is desirable. However, determining the full structure of an epitaxial thin film (lattice parameters, space group, atomic positions, surface reconstructions) on a routine basis is a serious challenge. In this paper we highlight the remarkable information that can be extracted from both the Bragg scattering and inelastic multiple scattering events that occur during Reflection High Energy Electron Diffraction. We review some methods to extract structural information and show how mature techniques used in other fields can be directly applied to the in-situ and real-time diffraction images of a growing film. These collections of techniques give access to both the epitaxially influenced 3-dimensional bulk structure of the film, and any reconstructions that may happen at the surface.
https://arxiv.org/pdf/1005.5364.pdf
_____
_____
- Badges
- Science topic
- Similar topics
- Philosophy
- Philosophy Of Science
- Reasoning